Practice Advisory Interim Guidance for Care of Obstetric Patients During a Zika Virus Outbreak

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About This Practice Advisory

Zika virus continues to be an area of evolving care and practice. Recommendations below are based on limited data. Fellows should check periodically for revisions and updates on ACOG’s Practice Advisories web page and Zika virus web page, CDC’s website, and SMFM’s website. ACOG and SMFM will communicate important changes and updates to this guidance.

This Practice Advisory represents the current information available regarding Zika virus. When new information becomes available, the entire Practice Advisory is reviewed and individual sections are updated as needed and dated accordingly.

Summary of Critical Updates

Below is a summary of recent critical updates to this Practice Advisory. All modules with the date September 13, 2017 contain new or revised information and should be reviewed.

  • Obstetric health care providers should continue to consult CDC’s World Map of Areas with Risk of Zika when assessing patients. In many countries the epidemic is over, however Zika is still likely to be endemic in various regions of the Americas. 
  • New data on currently available IgM tests show that IgM antibodies persist for at least four months following acute infection, thus making it difficult to determine if IgM detected during pregnancy represents an infection that is recent (during pregnancy) or one that occurred before pregnancy. IgM can also persist for a prolonged period of time potentially making timing of infection with subsequent pregnancies difficult to determine.
  • The number of false positive Zika tests has risen as the prevalence of Zika has decreased, and this compounds some of the limitations of  the IgM test.
  • CDC no longer recommends routine Zika virus testing for asymptomatic pregnant women with possible Zika exposure that is not ongoing*. However, testing of asymptomatic pregnant women without ongoing* possible exposure should be considered using shared decision making. See more in the Assessment and Testing section.
  • Some jurisdictions (e.g. those at increased risk for local transmission) will continue to recommend Zika testing for asymptomatic pregnant women due to increased risks of transmission. Therefore, obstetric providers should check regularly with their state and local health departments for information on testing asymptomatic pregnant women without ongoing* possible exposure.
  • The CDC now recommends concurrent IgM and NAT testing for symptomatic pregnant women with possible Zika exposure up to 12 weeks after symptom onset. Ideally, testing should be performed as soon as possible after symptoms begin. Revised testing Figure 1 & Figure 2 can be found in the Assessment and Testing module.

*Ongoing exposure is defined as currently living in or frequent travel (e.g. daily or weekly) to areas with Zika virus transmission.

In the Zika Practice Advisory
 
Background

(Updated: September 13, 2017)

Since reports of Zika virus in May 2015 in South America, the virus has spread throughout the Americas, including the U.S. The number of Zika cases is declining. In most places the epidemic is over and the virus is likely to be endemic. The CDC  web site maintains and updates the list of areas where Zika virus transmission has been identified, including a list of U.S. states and territories where active mosquito-borne Zika virus transmission is found (for current locations, see Travel Restrictions).

The virus spreads to humans primarily through infected Aedes species mosquitoes (Ae. aegypti and Ae. albopictus), from mother to her fetus during pregnancy, and through sexual contact, although Zika virus transmission may also occur through blood transfusion and through laboratory exposure. Zika virus disease is defined as having at least one of the following signs or symptoms: acute onset of fever, rash, arthralgia, conjunctivitis and laboratory confirmation of Zika virus infection. Based on data prior to 2015, it appears that only about one in five infected individuals will exhibit recognizable symptoms and most will have mild, nonspecific symptoms. Once a person is infected, the incubation period for the virus is approximately 3–14 days (Emerg Infect Dis 2017). This time frame is suggested based on limited experience from Zika virus cases as well as extrapolation from data on other flaviviruses. Possible Zika virus exposure is defined as travel to or residence in an area of active Zika virus transmission (http://www.cdc.gov/zika/geo/index.html), or sex without a condom with a partner who traveled to or lived in an area of active transmission. Anyone who lives or travels to an area where Zika virus is found and has not already been infected with Zika virus is at risk of contracting Zika virus. Once a person has been infected, he or she is likely to be protected from future infections, although this is based on limited data and experience from other flaviviruses and has not been confirmed.

It is not believed that pregnant women are at greater risk of Zika virus transmission than non-pregnant individuals. However, there is demonstrated causation between Zika virus infection during pregnancy and devastating adverse birth outcomes such as severe brain abnormalities, microcephaly, eye and hearing abnormalities and joint contractures. Zika can lead to a distinct pattern of birth defects among fetuses and infants born to women infected during pregnancy and this has been defined as the congenital Zika syndrome (Moore 2017).  The most severe cases of congenital Zika syndrome include:

  • Severe microcephaly with partially collapsed skull
  • Thin cerebral cortex with calcifications noted in the subcortical region
  • Macular scarring and focal pigmentary retinal mottling and other abnormalities on ophthalmologic examination of the retina
  • Congenital contractures – these can be in a single joint or in multiple joints – or arthrogryposis
  • Marked early hypertonia and symptoms of extrapyramidal involvement

A recent CDC Vital Signs report by the U.S. Zika Pregnancy Registry published data on 1,297 completed pregnancies with laboratory evidence of possible recent Zika virus infection in 2016 from 44 states. CDC found that in pregnant women with laboratory-confirmed Zika virus infection, approximately one in 10 had a fetus or baby with Zika-virus associated birth defects (24/250 completed pregnancies [10%, 95% CI = 7%-14%]). Birth defects were reported in a higher proportion of completed pregnancies with confirmed infections in the first trimester (15%) (95% CI = 8%-26%) (Reynolds 2017). Transmission of Zika virus to the fetus has been documented in all trimesters and a diagnosis of Zika infection during ANY trimester may be associated with fetal or neonatal abnormalities, including growth delays. Limited available data indicate that infection during the first and early second trimester are associated with a higher proportion of Zika related birth defects (Cauchemez 2016, Shapiro-Mendoza 2017). In addition, data analyzed from three birth defects surveillance programs demonstrated that the proportion of pregnancies with birth defects is approximately 20-fold higher, compared with the proportion seen before Zika was introduced into the region of the Americas in 2016 (Cragan 2017).

For more information and resources please refer to CDC Vital Signs Website.  

Zika has also been associated with other adverse pregnancy outcomes, including miscarriage and stillbirth. A recent cohort study from Brazil (Brasil 2016) found abnormal outcomes including stillbirth, growth restriction, and microcephaly and other sonographic abnormalities in 29% of fetuses of Zika virus-infected mothers in all trimesters. However, additional prospective studies are needed to establish the baseline versus attributable risk.

There currently is no vaccine or treatment for this infection. Several studies are underway to assess the efficacy of different vaccines.

View additional resources on the background of Zika virus.

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Travel Restrictions

(Updated: September 13, 2017)

Pregnant women should not travel to any area where there is a risk of Zika virus infection because Zika infection in a pregnant woman can cause severe birth defects in fetuses and infants. These areas include areas where the virus has been newly introduced or reintroduced and local mosquito-borne transmission is ongoing; areas where the virus was present before 2015 (endemic) and there is no evidence transmission has stopped; and areas where the virus is likely to be circulating but has not been documented. However, many people move regularly between areas with and without a risk of Zika virus infection to live, work, attend school, socialize, and seek medical care. Those who live in areas without active Zika transmission may not regard these activities as "travel." This context should be considered when asking women about travel history and potential exposure to Zika.  To help pregnant women and others identify areas of Zika risk, see CDC’s interactive World Map of Areas With Zika Risk to search for location-specific Zika information and travel recommendations. CDC updates Zika travel guidance regularly. Fellows should check CDC’s Zika Travel Notices periodically for updates.

Pregnant women and their partners who must travel to one of these areas should strictly follow steps to prevent mosquito bites during the trip and decrease the risk for sexual transmission (see Prevention).

Almost every state in the U.S. reported at least one case of a pregnant women with evidence of Zika virus in 2016 (Reynolds 2017). Most of these women acquired Zika virus infection during travel to an area with Zika (Reynolds 2017). All 51 cases of birth defects reported in the 2017 Vital Signs Report were traced to infections acquired in one of 16 countries or territories in Latin America or the Caribbean, including Puerto Rico (Reynolds 2017).

Travel Resources

CDC created and updated the following resources for providers and patients based on CDC’s recently updated recommendations for pregnant women and women and men of reproductive age:

  • Pregnant? Read This Before You Travel
    This guide provides information to pregnant women considering travel including the risks and symptoms of Zika, how to prevent Zika, and areas where travel is not recommended.

  • CDC’s Response to Zika: Counseling Travelers
    This guide describes recommendations to providers for counseling women and men of reproductive age who are considering travel to areas with risk of Zika. This material includes recommendations from CDC’s interim guidance and talking points to cover while discussing recommendations.  

  • CDC’s Response to Zika: Counseling Pregnant Travelers
    This guide describes recommendations to providers for counseling pregnant women who are considering travel to areas with risk of Zika. This material includes recommendations from CDC’s interim guidance¹ and talking points to cover while discussing recommendations.

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Prevention

(Updated: October 18, 2016)

Avoiding exposure is best:

  • When traveling to areas where Zika virus has been reported, women should take all precautions to avoid mosquito bites including the use of EPA-approved bug spray with DEET, covering exposed skin, staying in air-conditioned or screened-in areas, and treating clothing with permethrin.

  • Providers should specifically communicate to pregnant women that when used as directed on the product label, EPA-registered insect repellents, particularly those with DEET and permethrin, can be used safely during pregnancy.

  • These protective measures should be followed both day and night as the Aedes aegypti mosquito (which carries Zika virus) bites primarily during the day as well as at dusk and dawn. Reapplication of insect repellant should be practiced as directed on the product label.

  • Consistently and correctly using condoms during sex or abstaining from sex for the duration of the pregnancy is recommended if a patient has a sex partner that has traveled to or lives in an area with active Zika virus transmission. 

View additional resources on the prevention of Zika virus.

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Reproductive Counseling

(Updated: September 13, 2017)

Guidance related to reproductive counseling is outlined below. Please see the Assessment and Testing  module for guidance on testing of pregnant and non-pregnant women. 

Obstetrician–gynecologists and other health care providers should discuss pregnancy intentions and reproductive options with all women of reproductive age for shared decision making. In the context of the ongoing Zika virus outbreak, prepregnancy care should include a discussion of the signs and symptoms and the potential risks of Zika virus infection. Health care providers should discuss their patients’ reproductive life plans in the context of potential Zika virus exposure. View CDC's guide for preconception counseling in context of Zika virus exposure.

Sexual Transmission

Sexual transmission of Zika virus has been reported, including male-to-female and female-to-male transmission, when the sexual contact did not include a barrier to protect against infection, but the frequency and efficiency of this route of infection is uncertain (Musso, 2017). Barriers against infection include male or female condoms for vaginal sex, male condoms for oral sex, and male condoms cut to create a flat barrier or dental dams for oral sex.

Most reported sexual transmissions have been from persons with symptomatic Zika virus infections, although sexual transmission can occur from a man with asymptomatic Zika virus infection. Among reported cases of sexually transmitted Zika virus infection, the longest reported period between symptom onset and sexual contact that might have transmitted Zika virus was 32–41 days. 

Data on the detection of Zika virus RNA in semen can inform estimates of the time periods during which sexual transmission might occur. However, detection of Zika virus RNA in semen may not indicate the presence of infectious virus and thus the potential for sexual transmission. Many reports indicate that concentrations of detectable Zika virus RNA in semen decrease after infection, with the longest reported detection at 188 days after symptom onset. Culture is considered the best method for demonstrating the presence of replicative and thus infectious virus and Zika virus cultured from semen has been documented up to 69 days after symptom onset. 

Given the potential risks of maternal Zika virus infection, pregnant women with sex partners (male or female) who live in or have traveled to an area with active Zika virus transmission should consistently and correctly use condoms or other barriers against infection during sex (vaginal, anal, or oral) or abstain from sex for the duration of the pregnancy. 

Women who are not pregnant and men who want to reduce the risk for sexual transmission of Zika virus should use condoms or other barriers against infection consistently and correctly during sex (vaginal, anal, or oral) or abstain from sex when one sex partner has traveled to or lives in an area with active Zika virus transmission. 

These recommendations are based on expert opinion, data from other flaviviruses, the limited available data on Zika virus, and knowledge about risks for other viral infections in the prepregnancy period. For men, estimates are based on evidence that the virus may persist in semen for longer periods after exposure and infection.

Patients should be counseled that testing of specimens for risk of sexual transmission is not currently recommended for asymptomatic individuals because the performance of the test is not known in asymptomatic individuals (See Testing).  

More information on Zika virus, women and their partners.

Women Avoiding Pregnancy

For women who do not want to become pregnant, obstetrician–gynecologists and other health care providers should discuss strategies to prevent unintended pregnancy and provide counseling on family planning and the use of contraceptive methods. Safety, effectiveness, availability, and acceptability should be considered when selecting a contraceptive method(s).

The risk of adverse pregnancy and birth outcomes associated with Zika disease during pregnancy highlights the need to ensure that effective contraception is readily available for women and couples who live in or have recently traveled to areas with local Zika virus transmission and who do not desire pregnancy.

Women Who Desire Pregnancy

Both women who are diagnosed with Zika virus disease and asymptomatic women with possible exposure to Zika virus should consider waiting at least 8 weeks from symptom onset or exposure to attempt pregnancy. Their male partners with possible Zika virus exposure, regardless of symptom status, should consider waiting to attempt pregnancy until at least 6 months after symptom onset (if symptomatic) or last possible Zika virus exposure (if asymptomatic). This advice means that those living in areas with ongoing transmission of Zika virus may decide to delay pregnancy until the epidemiology of local transmission demonstrates no additional transmission. Those who are not planning to delay should talk with their health care providers about the risks. Obstetrician-gynecologists and other health care providers should counsel patients on the risks of Zika virus as part of their pregnancy planning and counseling. This should include counseling about the potential consequences to the fetus associated with Zika virus infection during pregnancy, such as microcephaly and other serious brain abnormalities (see Background). Health care providers should stress the use of mosquito prevention strategies while attempting pregnancy and during pregnancy (see Prevention). CDC has a suggested prepregnancy counseling script for providers:

Preconception Counseling Guide for Men and Women Living in Areas With a CDC Zika Travel Notice Who Are Interested in Conceiving

No instances of Zika virus transmission during fertility treatment have been documented, but transmission through gametes or embryos is theoretically possible. Recommendations for sexually intimate couples with Zika virus infection or possible Zika virus exposure undergoing fertility treatment with their own gametes and embryos should follow the testing and timing recommendations as described above; recommendations might need to be adjusted depending on individual circumstances. The U.S. Food and Drug Administration has issued guidance to reduce the risk of Zika virus transmission by donated human cells, tissues, and cellular and tissue-based products, including reproductive tissues.

Emerging epidemiologic and laboratory data indicate that Zika virus IgM can persist beyond 12 weeks in a subset of infected people. Additionally, consistent with what is known about other flaviviruses, unpublished preliminary data indicate a median of four months to the first negative Zika virus IgM result (Roehrig, 2003). Therefore, some women who test positive for IgM antibody during pregnancy may have been infected with Zika virus and developed an IgM response before pregnancy and do not have a recent Zika infection.

For non-pregnant women who want to become pregnant in the near future and who have an ongoing* risk of Zika virus exposure, obstetrician gynecologists and other healthcare professionals can consider testing for Zika antibodies. Antibody test results before pregnancy should not be used to determine if it is safe for a woman to become pregnant because of the risk of false positive results and lack of correlation between IgM results in this setting and actual immunity.        

It is important to note that the test results represent a single point in time and women who live in areas with a CDC Zika travel notice and who have never been infected with Zika virus are at continued risk of getting Zika.

*Ongoing exposure is defined as currently living in or frequent travel (e.g. daily or weekly) to areas with Zika virus transmission

View additional resources on reproductive counseling and Zika virus


Assessment and Testing

(Updated: September 13, 2017)

Assessment

All pregnant women in the U.S. and U.S. territories should be assessed for possible Zika virus exposure and symptoms at each prenatal care visit. Obstetrician-gynecologists and other health care providers should continue to ask pregnant women at each prenatal visit about possible Zika virus exposure (e.g., travel to, or residence in an area with risk for mosquito-borne Zika virus transmission or sex with a partner who has traveled to or resides in an area with risk for mosquito-borne Zika virus transmission), specifically before and during the current pregnancy. Obstetrician-gynecologists and other health care providers should ask about presence of symptoms of Zika virus disease (e.g., fever, rash, arthralgia, and conjunctivitis) and place, duration, and type of travel to assess a woman’s potential for Zika virus exposure. Data from other mosquito-borne illnesses indicate that intensity of transmission, duration of travel, and type of travel influence the likelihood of infection; these factors might also affect the likelihood of Zika virus acquisition. Knowledge of a pregnant woman’s possible exposure to Zika virus before and during pregnancy is critical contextual information that should be used to tailor pretest and posttest counseling and interpretation of test results. See Box 1Key Information Needed for Deciding Whether to Test and How to Interpret Serology Results

Testing

CDC has updated its interim guidance on Zika testing for pregnant women.

In summary:

  • New data on currently available IgM tests show that IgM antibodies persist for at least four months following acute infection, thus making it difficult to determine if IgM detected during pregnancy represents an infection that is recent (during pregnancy) or one that occurred before pregnancy. IgM can also persist for a prolonged period of time potentially making timing of infection with subsequent pregnancies difficult to determine.
  • The number of false positive Zika tests has increased with decreasing prevalence of Zika and this compounds some of the limitations of the IgM test.
  • CDC no longer recommends routine Zika virus testing for asymptomatic pregnant women with possible Zika exposure that is not ongoing*. However, testing of asymptomatic pregnant women without ongoing* possible exposure should be considered using shared decision making.
  • Some jurisdictions (e.g. those at increased risk for local transmission) will continue to recommend Zika testing for asymptomatic pregnant women due to increased risks of transmission. Therefore, obstetric providers should check regularly with their state and local health departments for information on testing asymptomatic pregnant women without ongoing* possible exposure.
  • The CDC now recommends concurrent IgM and NAT testing for symptomatic pregnant women with possible Zika exposure up to 12 weeks after symptom onset. Ideally, testing should be performed as soon as possible after symptoms begin. Revised testing Figure 1 and Figure 2 can be found in this module.

Nucleic acid tests (NATs) and serologic tests are available to detect Zika virus infection, although each test has limitations. Nucleic acid tests (NATs) is a generic term referring to all molecular tests, including real-time reverse transcription polymerase chain reaction (rRT-PCR). Most, but not all, of the molecular tests that have received Emergency Use Authorization (EUA) from the FDA are RT-PCR-based. Therefore, the term NATs would encompass non-RT-PCR molecular tests. Serologic tests to detect Zika virus infection include immunoglobulin M (IgM) and plaque reduction neutralization (PRNT) tests.

Other diagnostic methods, such as NAT testing of amniocentesis specimens, if amniocentesis is performed for other reasons, or serial ultrasounds, may provide additional information to help determine whether the IgM test results suggest a recent infection. Providers should counsel women on the limitations of all tests. Please reference CDC’s Guidance for U.S. Laboratories Testing for Zika Virus Infection for more information.

Currently, there is no Immunoglobulin G (IgG) Gig test approved in the U.S. to reliably test for acquired immunity to Zika virus. Efforts to develop and validate Zika virus serologic assays with improved specificity for Zika virus infection and the ability to distinguish a recent infection from a previous infection are ongoing. CDC is currently working with multiple manufacturers to validate tests in development and will update testing recommendations as new information becomes available. Please refer to the FDA for a current list of available assays and associated letters of authorization, fact sheets and product labeling.

Providers should counsel women on the limitations of all tests. It is important to note that IgM testing of pregnant women with possible exposure to Zika virus has many limitations:

1) IgM tests may cross react with antibodies to other flaviviruses such as Dengue and Chikungunya

2) IgM may persist for up to four months in some who are infected making it difficult to determine if an infection is recent

3) The sensitivity and specificity of the current IgM tests are worse with decreasing prevalence of disease

Therefore, the CDC no longer recommends routine testing of individuals with a low pretest probability as the false positive rate will be high. In addition, using this test to time infection in pregnancy will be difficult for those who may have been infected just prior to pregnancy if they live in areas with ongoing infection.

Testing of Pregnant Women

Pregnant women who have potentially been exposed to Zika virus (i.e., via travel or sexual contact) should be tested according to Figures 1 & 2. Testing for asymptomatic, non-pregnant sexual partners (with or without potential Zika exposure) of pregnant women is not currently supported by CDC guidelines.

Pregnant women who live in or travel frequently to areas of local transmission (or whose partners live in or travel frequently to these areas) should be managed as though they have an ongoing* risk for Zika virus infection; pregnant women who have traveled to these areas (or whose partners have traveled to these areas) should be managed as though they have had recent Zika virus exposure.

Testing and Evaluation of Pregnant Women (Figures 1 & 2):

Zika virus testing of pregnant women should follow the algorithms in Figure 1 and Figure 2, noting that inconclusive or equivocal test results should be repeated. Testing recommendations by area of travel are outlined by CDC in this World Map

Zika virus testing is performed at the CDC Arbovirus Diagnostic Laboratory, most state health departments, and some commercial laboratories per FDA's Zika virus emergency use authorization. Currently, it is not certain that all laboratories performing NATs offer Zika IgM testing or confirmatory serologic testing such as PRNT. Therefore, the full complement of recommended tests may not be done automatically. If a positive IgM result is obtained, this requires confirmatory testing with PRNT. Most of these tests will need to be shipped to CDC or several other select laboratories that have PRNT capability.   For the fastest results, ACOG recommends that ob-gyns use labs that have combined NATs and IgM, and ideally PRNT* testing. Many state health departments have combined testing. Some commercial labs offer combined NAT and IgM testing. Whole blood specimens should be stored at 2-8°C and tested within one week of collection. ACOG encourages providers to contact their state health department or their commercial laboratory to be aware of how their laboratory performs Zika virus testing so that providers can retain or collect additional serum specimens as needed.  

Providers should follow CDC’s information on how to best collect and submit body fluids for Zika virus testing and should indicate a patient’s pregnancy status when submitting serum samples. While the CDC has made efforts to expand the availability of testing, priority for Zika virus testing should be given to pregnant women with possible exposure.

For those patients who have a recent (0-12 weeks) or ongoing* exposure, testing recommendations vary depending on time of exposure and whether or not symptoms are present. It is important to note that symptomatic pregnant women should be tested as soon as possible after symptom onset. Additionally, regardless of symptoms, testing is not recommended unless there is a recent past or ongoing* exposure. 

The decision to continue routine testing of asymptomatic pregnant women without ongoing* risk for Zika virus exposure should be made by local health officials based on information about levels of Zika virus transmission and laboratory capacity (See Box 1 for more information). 

Symptomatic Pregnant Women with Possible Exposure

All symptomatic pregnant women with possible Zika exposure should be tested according to Figure 1. Pregnant women should be tested as soon as possible through 12 weeks after symptom onset. Pregnant women should be tested using concurrent Zika NAT (serum and urine) and Zika IgM (serum). Because of the potential for false-positive NAT results, updated recommendations include NAT testing of both serum and urine and concurrent Zika virus IgM antibody testing to confirm the diagnosis of acute Zika virus infection with more than one test.

Interpretation of test results should follow CDC’s Interpretation of Results of Nucleic Acid and Antibody Testing for Zika Virus Infection (Table 1).

For women who seek care >12 weeks after symptom onset, Zika virus IgM testing might be considered; however, a negative result does not rule out an infection during pregnancy because IgM levels decline over time. A positive result should be interpreted within the context of the known limitations of serologic testing.

Asymptomatic Pregnant Women With Ongoing* Possible Exposure

For asymptomatic pregnant women with ongoing* possible exposure to Zika virus, testing for Zika virus infection should be offered as part of routine obstetric care because it might identify acute infection during pregnancy (Figure 2). IgM testing is no longer routinely recommended because of the limitations of IgM tests and the difficulty in interpreting results. Persons with ongoing* possible Zika virus exposure include those who reside in or frequently travel (e.g., daily or weekly) to an area with risk for Zika virus transmission.

NAT for asymptomatic pregnant women should be informed by jurisdictional trends in Zika virus transmission, the duration of ongoing* possible exposure during pregnancy, and data on the duration of Zika virus RNA detection in body fluids. For pregnant women who have received a diagnosis of laboratoryconfirmed Zika virus infection any time before or during the current pregnancy, additional Zika virus testing is not recommended. For women without a prior laboratory-confirmed diagnosis of Zika virus, NAT should be offered at the initiation of prenatal care, and if Zika virus RNA is not detected on clinical specimens, two additional NAT tests should be offered during the course of the pregnancy coinciding with prenatal visits. Local jurisdictions have adopted different recommendations regarding the timing of testing so it is best to check with the local health department to follow their recommendations.

The implications of Zika infection occurring in the third trimester are still being investigated. However, NAT testing in the third trimester is already performed in some jurisdictions and can be considered as part of clinical management. However, as new data emerges, recommendations regarding repeat testing for pregnant women with ongoing* risk for Zika virus transmission will be updated. 

Asymptomatic Pregnant Women With Recent Possible Exposure but Without Ongoing* Possible Exposure

Asymptomatic pregnant women who have recent possible Zika virus exposure (i.e., through travel or sexual exposure) but without ongoing* possible exposure are not routinely recommended to have Zika virus testing.

However, testing can be considered using a shared decision-making model, one in which patients and providers work together to make decisions about testing based on patient preferences and values, clinical judgment, a balanced assessment of risks and expected outcomes, and the jurisdiction’s recommendations. Obstetrician-gynecologists and other health care providers should consider the extent of exposure when deciding whether to advise testing including type and length of exposure, Zika virus transmission trends at location of exposure and the use of prevention measures (e.g., insect repellent, appropriate clothing, and condom use). See Box 1 and Testing Resources for more information.

Jurisdictional recommendations may take into account the epidemiology of Zika virus transmission and other epidemiologic considerations (e.g., seasonality and mosquito surveillance and control factors) in areas with risk for Zika virus transmission and, therefore, might include a routine recommendation to test asymptomatic pregnant women either for clinical care or as part of Zika virus infection surveillance.

Of note, based on the epidemiology of Zika virus transmission and other epidemiologic considerations (e.g., seasonality), jurisdictions might recommend testing of asymptomatic pregnant women, either for clinical care or as part of Zika virus surveillance. In this case, testing should follow the updated guidelines for symptomatic pregnant women. ACOG members should check with their state and local health department for asymptomatic testing recommendations in their area.

More on when to test for Zika virus 

Routine Zika virus testing is not currently recommended for women or men with possible Zika virus exposure without clinical illness who are attempting pregnancy. For men, this advice in part reflects uncertainty about whether molecular or serologic testing reflects the presence or absence of Zika virus in semen.

Testing of specimens to assess risk for sexual transmission is currently not recommended. However, Zika virus testing of serum and urine is recommended for persons who have had possible sexual exposure to Zika virus and who develop signs or symptoms consistent with Zika virus disease.

Providers should report all cases of Zika virus disease to local and state health departments, including those suspected to have occurred by sexual transmission.

*Note: PRNT is not currently routinely recommended in Puerto Rico for specimens that have “Positive, Presumptive, Equivocal or Possible” Zika interpretations based on testing with current EUA authorized Zika IgM test. For everywhere else, PRNT is very important to rule out false positive IgM results

FIGURE 1Updated interim testing recommendations*,†,§,¶,**,††,§§ and interpretation of results¶¶ for symptomatic pregnant women with possible Zika virus exposure***,††† — United States (including U.S. territories), July 2017

View full-size version of Figure 1


FIGURE 2Updated interim testing recommendations*,†,§ and interpretation of results¶,** for asymptomatic pregnant women with possible Zika virus exposure††,§§,¶¶ — United States (including U.S. territories), July 2017

View full-size version of Figure 2

 

Box 1: Key Information Needed for Deciding Whether to Test and How to Interpret Serology Results

View full-size version of Box 1

TABLE 1Interpretation*,† of results of nucleic acid and antibody testing§,¶ for suspected Zika virus infection — United States (including U.S. territories), July 2017

Abbreviations: IgM = immunoglobulin M; NAT = nucleic acid test; PRNT = plaque reduction neutralization test.

* Final interpretations of results of Zika virus tests should be performed after all testing is completed.

† Serology test results that indicate flavivirus infection should be interpreted in the context of circulating flaviviruses.

§ Dengue virus IgM testing is recommended for symptomatic pregnant women as well as for asymptomatic pregnant women residing in areas where PRNT is not recommended.

¶ Currently, PRNT confirmation is not routinely recommended for persons living in Puerto Rico.

** Serum must be submitted for all persons tested for Zika virus infection; a urine specimen for Zika virus NAT testing should always be submitted concurrently with a serum specimen.

†† For laboratory interpretation in the presence of dengue virus IgM results refer to https://www.cdc.gov/dengue/clinicallab/laboratory.html.

§§ Positive results include “positive,” “presumptive Zika virus positive,” or “possible Zika virus positive.” These are examples of assay interpretations that might accompany test results; positive serology terminology varies by assay. For explanation of a specific interpretation, refer to the instructions for use for the specific assay performed. Information on each assay can be found at https://www.fda.gov/MedicalDevices/Safety/EmergencySituations/ucm161496.htm#zika under the “Labeling” tab for the specific assay.

¶¶ Nonnegative results include “positive,” “equivocal,” “presumptive positive,” or “possible positive.” These are examples of assay interpretations that might accompany test results; nonnegative serology terminology varies by assay. For explanation of a specific interpretation, refer to the instructions for use for the specific assay performed. Information on each assay can be found at https://www.fda.gov/MedicalDevices/Safety/EmergencySituations/ucm161496.htm#zika under the “Labeling” tab for the specific assay.

*** Zika virus IgM positive result is reported as “presumptive positive or flavivirus infection” to denote the need to perform confirmatory PRNT titers against Zika virus, dengue virus, and other flaviviruses to which the person might have been exposed to resolve potential false-positive results that might have been caused by cross-reactivity or nonspecific reactivity. In addition, ambiguous test results (e.g., inconclusive, equivocal, and indeterminate) that are not resolved by retesting also should have PRNT titers performed to rule out a false-positive result. However, PRNT confirmation is currently not routinely recommended for persons living in Puerto Rico.

View full-size version of Table 1


Testing Resources
  • Screening Pregnant Women for Zika Testing
    Use this tool to evaluate pregnant women for exposure to Zika virus and symptoms of Zika virus disease to determine whether testing is indicated. Visit CDC’s map to determine areas with risk of Zika.
  • Clinician Guide
    For Asymptomatic Pregnant Women With Exposure to Areas With a CDC Zika Travel Notice.

 *Ongoing exposure is defined as currently living in or frequent travel (e.g. daily or weekly) to areas with Zika virus transmission. 


Clinical Management of a Pregnant Woman with Suspected Zika Virus Infection

(Updated: September 13, 2017)

The many uncertainties about Zika virus biology highlight the challenges of managing and counseling about exposures and infection in pregnancy. Referral to a maternal–fetal medicine or infectious disease specialist with expertise in pregnancy management is recommended and may be useful particularly for those pregnancies with demonstrated maternal infection or concerning fetal findings. 

Given that serology test results can be difficult to interpret, particularly in persons who were previously infected with or vaccinated against flaviviruses, and because of the adverse outcomes caused by Zika virus infection during pregnancy are not fully described, pregnant women with laboratory evidence of recent flavivirus infection are considered to have possible Zika virus infection and should be monitored frequently.

Persistent detection of Zika virus RNA in serum has been reported during pregnancy. As new data emerge, recommendations regarding repeat ZIKV RNA NAT in pregnant women will be updated.

It is important that maternal Zika virus exposure and testing information be available and communicated to the pediatric provider so that appropriate infant testing and management can be implemented in accordance with existing guidance. It is particularly important that this information be conveyed while neonates are hospitalized after birth to allow for collection of infant specimens within 2 days of birth. CDC’s Zika Care Connect has established a network of specialized healthcare providers who have agreed to care for families affected by Zika.

Fetal Evaluation

Prenatal ultrasonography to evaluate for fetal abnormalities consistent with congenital Zika virus syndrome is recommended for all pregnant women tested for Zika, regardless of laboratory findings. Importantly:

Ultrasound examinations should be used to assess fetal anatomy, particularly neuroanatomy, and to monitor growth. They should focus on development of findings such as intracranial calcifications, microcephaly, ventriculomegaly, arthrogryposis; abnormalities of the corpus callosum, cerebrum, cerebellum, and eyes; and other brain abnormalities, as those abnormalities have been most frequently reported in affected pregnancies. The  International Society of Ultrasound in Obstetrics and Gynecology offers a tutorial to help providers learn more on how to improve their Congenital Zika Virus Syndrome diagnostic capabilities.

Ultrasound examinations, particularly if obtained close to the time of infection, may not preclude later manifestations, and cases with substantial delayed findings have been reported. These  reports include infants without microcephaly at birth who later exhibited head growth deceleration occurring to the point of microcephaly after birth. Many of these infants had abnormal brain imaging after birth by CT or MRI, and many exhibited varying degrees of abnormalities, including dysphagia, seizures, and hypertonia/dystonia. Only three infants were reported to have a history of prenatal ultrasound examination abnormalities consistent with congenital Zika virus infection. Of note, data suggest that severe adverse outcomes appear to be more common but are not limited to women infected in the first trimester. Additional data suggest that severe adverse outcomes are not limited to symptomatic pregnant women.

New data suggest there is a substantial delay between infection and fetal abnormalities. In a study of 17 confirmed cases of prenatal maternal Zika infection in Columbia, of the 14 symptomatic cases, researchers found that there was a delay of at least 15 weeks (range 15-24 weeks) between infection onset and the presentation of fetal abnormalities (Parra-Saavedra, 2017).

Repeat imaging should be considered if Zika testing suggests infection. If maternal testing does not suggest infection and exposure is not ongoing*, serial ultrasound examinations are unlikely to be needed.

When imaging raises suspicion for fetal infection, amniocentesis for Zika virus testing of amniotic fluid may be considered on a case by case basis. While it is assumed that assay performance on amniotic fluid is similar to that with maternal serum, this is not certain. Nor is it known how long after a pregnant woman becomes infected she can transmit the virus to the fetus, for what duration amniotic fluid will be ZIKV RNA NAT positive, or what the ability of the test is to determine the presence of fetal injury.

Counseling During Pregnancy

Obstetrician-gynecologists and other obstetric providers should be prepared to counsel pregnant women exposed to or infected with Zika about the virus and their options related to the pregnancy. Like all pregnant women, Zika-infected pregnant women should have full access to the complete range of reproductive options, including termination of pregnancy.

Counseling related to Zika virus should be individualized. Topics to be addressed include the following:

  • There is much that is still unknown about the effects of Zika virus on a fetus. Scientists are studying the virus and its effects in pregnancy, and the medical community’s understanding is evolving, but there is a lot of uncertainty.
  • All pregnant women infected or presumptively infected with Zika virus should be offered comprehensive options counseling, including a thorough discussion of pregnancy continuation, termination of pregnancy, and adoption. As with all patient counseling, health care providers must not seek to impose their personal beliefs upon their patients nor allow personal beliefs to compromise patient health, access to care, or informed consent.
  • If Zika testing for a pregnant woman is indicated, health care providers should provide pretest counseling. Health care providers should provide patients with information on the complexity of Zika testing including information that testing for Zika can result in false-positives and false-negatives, making it difficult to exclude infection. Limitations of laboratory tests used to diagnose Zika virus infection should also be discussed with pregnant women.
  • Patients should be made aware that more than one Zika test may be required before a final result is determined and that understanding test results can be challenging. Patients should also be counseled that previous exposure to Zika virus could affect test results during pregnancy.
  • Obstetrician gynecologists and other health care providers should discuss each type of Zika test with the patient and what test results could mean for their pregnancy. CDC has developed several scripts for providers when counseling patients about testing. See CDC’s resources for pretest counseling.
  • Ultrasound examinations, especially if obtained close to the time of infection, may not rule out later manifestations, and cases with delayed findings have been reported.
  • When an ultrasound examination is performed, patients should be counseled about the limitations of ultrasonography. More information about ultrasonography is available in ACOG’s Ultrasonography in Pregnancy Practice Bulletin.
  • Congenital Zika syndrome — a recently recognized pattern of congenital anomalies associated with Zika virus infection during pregnancy that includes microcephaly, intracranial calcifications or other brain anomalies, or eye anomalies, among others — may present well after birth. Therefore, normal ultrasound findings during the antenatal period do not rule out neonatal sequelae of Zika infection developing or manifesting after birth.

Populations and geographic areas at higher risk of Zika infection may have reduced access to abortion care. Access to second trimester abortion may be especially limited and may require travel, including travel to another state. Obstetrician-gynecologists and other obstetric care providers who do not provide abortion care should be prepared to refer patients.  In addition, providers should be prepared to provide patients with information about abortion funds that provide financial support to women seeking abortion.

Counseling Resources

Obstetrician-gynecologists and other health care providers should encourage pregnant women to avoid travel to areas with Zika and advise pregnant women on how to protect themselves and their partners from mosquito bites and from getting Zika through sex. CDC has suggested scripts for providers to use with pregnant patients as follows:

CDC has additional pregnancy-related patient counseling materials on Zika.

ACOG’s Position Statement Counseling Patients With Zika Infection


Reporting

Obstetrician–gynecologists will need to report pregnant women with any laboratory evidence of Zika virus infection (positive or inconclusive test results) as well as any adverse outcomes to the state health department (see U.S. Zika Pregnancy Registry for details).

*Ongoing exposure is defined as currently living in or frequent travel (e.g. daily or weekly) to areas with Zika virus transmission.


Breastfeeding

(Updated September 13, 2017)

Although the presence of Zika virus in breast milk has been reported, there are no reports of infants getting Zika virus through breastfeeding. Infection through oral intake is not known.

CDC and WHO guidance currently recommend that infants born to women with suspected, probable, or confirmed Zika virus infection, or who live in or have traveled to areas with Zika, should continue to breastfeed according to established infant feeding guidelines. While Zika virus has been detected in breast milk, including recent evidence of viral persistence and high viral load in breast milk (Sotelo, 2017), there are no reports of transmission of Zika virus infection through breastfeeding. Based on the available data, the health benefits of breastfeeding continue to outweigh the possible risk of transmission and potential outcomes of postnatally acquired Zika infection, including severe disease and/or long term complications (WHO 2016, Colt 2017, Russell 2016). Much is still unknown about the potential transmission of Zika virus to newborns who are breastfed or the possible outcomes of such postnatally acquired infection. Further studies are needed to better understand the potential transmission of Zika virus to newborns. CDC guidance will be updated when additional data become available regarding Zika virus transmissibility from breastfeeding and related outcomes of postnatal Zika infection.

Given the benefits of breastfeeding and the lack of evidence that postnatal Zika virus infection is more severe, breastfeeding is encouraged for women living in areas with ongoing Zika virus transmission, including women with documented Zika virus infection. 


Postnatal Management

(Updated: September 13, 2017)

An important feature of the CDC guidance is the recommendation that specimens obtained after Zika virus or flavivirus infection is suspected or diagnosed should be sent to pathology for further evaluation according to CDC’s guidance on collecting and submitting fetal tissue specimens for Zika virus testing.

Testing placental tissue specimens from pregnancies with possible Zika virus exposure that result in live births can be considered for diagnostic purposes in certain scenarios. It may be considered for symptomatic pregnant women and women with infants with possible Zika virus–associated birth defects, without a definitive diagnosis of laboratory-confirmed Zika virus infection during pregnancy (Table 2). Similar to the updated testing recommendations for asymptomatic pregnant women who have recent possible Zika virus exposure but without ongoing* possible exposure, testing of placental tissues is not routinely recommended; however, it should be considered for women who have a fetus or infant with possible Zika virus–associated birth defects.

Testing of placental and fetal tissues may be considered in selected scenarios for pregnancies resulting in a miscarriage or fetal loss/stillbirth (and testing of autopsy tissues in the event of an infant death) to provide insight into the potential etiology of the fetal loss or infant death (Table 2), which could inform a woman’s future pregnancy planning. Additional information is available at https://www.cdc.gov/zika/laboratories/test-specimens-tissues.html.


TABLE 2. Interim guidance for Zika virus testing* of formalin-fixed, paraffin-embedded placental, fetal, or infant autopsy tissues† for completed pregnancies with possible Zika virus exposure§ during pregnancy¶ — United States (including U.S. territories), July 2017

Abbreviations: IHC = immunohistochemistry; NAT = nucleic acid test; RT-PCR = reverse-transcription polymerase chain reaction.                                                                             

* Zika virus testing on formalin-fixed, paraffin embedded tissue specimens is conducted at CDC’s Infectious Diseases Pathology Branch (IDPB) and includes Zika virus RT-PCR on placental and fetal/infant tissues. Zika virus IHC may be performed on placental tissues into the second trimester, fetal tissues from any gestational age, and infant autopsy tissues.                                                                

† Placental tissues include placental disc, umbilical cord, and fetal membranes. Zika virus RNA can be focal within placental tissues, and testing of three sections of placenta, one section of umbilical cord, and one section of fetal membrane is recommended (https://www.cdc.gov/zika/laboratories/test-specimens-tissues.html). For pregnancy losses and infant deaths, submission of placental tissues in addition to fetal or infant autopsy tissues, if available, is preferred, but if not available will not preclude placental testing.                                                                              

§ Possible Zika virus exposure includes travel to or residence in an area with risk for Zika virus transmission (https://www.cdc.gov/zika/geo/index.html) during pregnancy or the periconceptional period (8 weeks before conception [6 weeks before the last menstrual period]), or sex without a condom, during pregnancy or the periconceptional period, with a partner who traveled to, or resides in an area with risk for Zika virus transmission.                                                                               

¶ Zika virus testing is not routinely recommended for asymptomatic pregnant women with recent possible Zika virus exposure but without ongoing exposure and who have a fetus or infant without Zika virus–associated birth defects.                                                                               

** In the event of a confirmed maternal acute Zika virus infection or confirmed congenital Zika virus infection in the infant (e.g., a positive NAT), placental testing from live births is not indicated. Currently, placental testing does not routinely provide additional diagnostic information in the setting of a maternal or infant diagnosis of acute or congenital Zika virus infection, respectively.                                       

†† For women with no possible Zika virus exposure before the current pregnancy, a positive IgM result likely represents acute Zika virus infection, and placental testing is not indicated.                                                          

§§ All or part of possible maternal Zika virus exposure, or symptom onset occurred >12 weeks before maternal serum specimen was collected.                                                                              

¶¶ Includes pregnant women with negative Zika virus NAT and negative Zika virus IgM ≤12 weeks after symptom onset or exposure.                                                                         

*** Possible Zika virus–associated birth defects that meet the CDC surveillance case definition include the following: brain abnormalities and/or microcephaly, intracranial calcifications, ventriculomegaly, neural tube defects and other early brain malformations, eye abnormalities, or other consequences of central nervous system dysfunction including arthrogryposis (joint contractures), congenital hip dysplasia, and congenital deafness (https://www.cdc.gov/zika/geo/pregnancy-outcomes.html). In all cases, infants or fetuses with possible Zika virus–associated birth defects should also be evaluated for other etiologies of congenital anomalies.                                                                    

††† Testing may be considered on a case-by-case basis, consult CDC for case-specific questions at https://www.cdc.gov/zika/laboratories/test-specimens-tissues.html. Infant testing and management should follow CDC guidelines, noting that cord blood specimens should no longer be submitted.

These recommendations will be updated as additional data emerge.

View full-size version of Table 2.

*Ongoing exposure is defined as currently living in or frequent travel (e.g. daily or weekly) to areas with Zika virus transmission.



Neonatal Outcomes and Evaluation

(Updated: September 13, 2017)

CDC reported that in 2016 about 1 in 3 babies with possible congenital Zika infection had no report of Zika testing at birth. Only 1 in 4 babies with possible congenital Zika infection were reported to have received brain imaging after birth (Reynolds 2017). Obstetrics providers, as well as the facilities and systems in which obstetric and neonatal/pediatric management take place, play a critical role in providing in evaluating and managing pregnant women with possible Zika virus exposure and ensuring this information is communicated to pediatric providers. Zika virus Identification and follow-up care of infants born to mothers with laboratory evidence of possible recent Zika virus infection during pregnancy and infants with congenital Zika virus infection can ensure that appropriate intervention services are available to affected infants.

Infants who meet one or more of the published criteria for testing for congenital Zika virus infection should be tested and evaluated in accordance with the updated CDC interim guidance for the evaluation and management of infants with possible Zika virus infection. However, considering the updated testing recommendations that will likely reduce routine Zika virus testing of asymptomatic pregnant women with recent possible Zika virus exposure but without ongoing* possible exposure, it is critical that pediatric health care providers inquire about possible maternal and congenital Zika virus exposure for every newborn.

This guidance also applies to infants born to mothers with negative maternal testing in the setting of ongoing* possible Zika virus exposure or a possible Zika virus exposure that occurred more than 12 weeks before maternal testing.

CDC has issued Clinical Guidance for Healthcare Providers Caring for Infants & Children and New Considerations for Testing of Infants with Possible Congenital Zika Virus Infection.

*Ongoing exposure is defined as currently living in or frequent travel (e.g. daily or weekly) to areas with Zika virus transmission. 


Reporting and the U.S. Zika Pregnancy Registry

(Updated: August 3, 2016)

As part of the response to the Zika outbreak, the CDC, in collaboration with state, tribal, local, and territorial health departments, established a pregnancy registry for comprehensive monitoring of pregnancy and infant outcomes following possible Zika virus infection. The registry is an active surveillance system of pregnant women with laboratory evidence of possible or confirmed Zika virus infection in the 50 U.S. states and DC, and in the U.S. territories. Detailed information about the registry includes weekly reporting of the number of pregnant women followed in the registry.

Obstetrician–gynecologists will need to report pregnant women with any laboratory evidence of Zika virus infection (positive or inconclusive test results) as well as any adverse outcomes to the state health department. They can expect follow-up from health officials during the pregnancy and at the time of expected birth to collect surveillance data. CDC registry staff will work with state health departments to assist with collection of information. Ob-gyns can also contact the CDC pregnancy hotline (call 770-488-7100 or email ZikaPregnancy@cdc.gov) to discuss women with laboratory evidence of Zika virus infection. If they contact CDC for clinical consultation, registry staff will ensure that state, tribal, local, or territorial health departments are notified.

ACOG strongly encourages all members to support the registry by reporting eligible cases and by designating staff who can assist in the completion of pregnancy data collection forms and who will be responsible for reporting pregnant women with Zika virus to their health department.

Understanding the range of health effects linked with Zika infection during pregnancy, as well as which pregnancies may be at risk for poor outcomes is essential. The data collected through these registries will be used to update recommendations for diagnostic testing, prenatal care and monitoring, and counseling of pregnant women and families affected by Zika virus. Information about the number of pregnant women affected will also assist in planning for services for these women, infants and families. Each new data point collected through these surveillance systems contributes to what we know about Zika virus, which will improve the care we provide to patients affected by the virus.

To better facilitate reporting, the CDC has provided a list of U.S. Zika Pregnancy Registry contacts for each state (members only PDF) and Provider and Patient fact sheets on the Zika registry reporting requirements.

For additional questions about the registry please e-mail ZikaPregnancy@cdc.gov or call 770-488-7100.

View additional resources on the U.S. Zika Pregnancy Registry

 >>Back to top


Infection Control Considerations

(Updated: September 13, 2017)

Zika virus RNA has been detected in many body fluids, including blood, urine, saliva, breast milk, and amniotic fluid and minimizing exposures to body fluids is important. CDC, ACOG and SMFM recommend Standard Precautions in health care settings to protect obstetrician–gynecologists and other health care providers and patients from infection with Zika virus as well as from blood-borne pathogens. This emphasizes what should already be usual and expected practice. Adherence to Standard Precautions, the basic infection prevention measures that apply to patient care in all heath care settings, is necessary to protect health care providers and patients in labor and delivery settings from transmission of Zika virus, as well as blood-borne pathogens, such as human immunodeficiency virus and hepatitis C. The appropriate use of personal protective equipment is important for all health care providers to minimize the risk of transmission of infectious pathogens through exposure to blood and body fluids. There is no evidence that contact precautions or respiratory isolation of Zika virus-infected patients is warranted.

In light of the recent case of Zika in Utah, CDC and ACOG have reviewed infection control considerations for health care providers and continue to recommend Standard Precautions. However, the CDC and ACOG continue to monitor the topic and any new or additional information will be posted as it becomes available.

See CDC’s new guidelines on Infection Control and ZIKV: Considerations for Labor and Delivery Units.

View additional resources on infection control considerations and Zika virus.

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Zika Virus and Blood Transfusion

(Updated: September 14, 2016)

To date, there have been no confirmed blood transfusion-transmission cases in the US, although there have been suspected cases of Zika transmission through blood transfusion in Brazil. Blood screening via questionnaire is performed throughout the U.S. However, because there is a strong possibility that Zika virus can be spread through blood transfusions, the FDA recommends that U.S. states and territories screen individual units of donated Whole Blood and blood components with a blood screening test authorized for use by the FDA under an investigational new drug application, or a licensed test when available. Alternatively, an FDA-approved pathogen-reduction device may be used for plasma and certain platelet products.

The CDC offers an overview of Zika and blood transfusion, including additional resources for blood collection centers and health departments. Clinical inquiries related to Zika and blood transfusions can be emailed to ocod@fda.hhs.gov.

>>Back to top


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(Updated: September 13, 2017)

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Oduyebo T, Polen KD, Walke HT, Reagan-Steiner S, Lathrop E, Rabe IB, et al. Update: interim guidance for health care providers caring for pregnant women with possible Zika virus exposure - United States (including U.S. territories), July 2017. MMWR Morb Mortal Wkly Rep 2017;66:781-93. Available at: https://www.cdc.gov/mmwr/volumes/66/wr/mm6629e1.htm. Retrieved August 29, 2017. 

Olson CK, Iwamoto M, Perkins KM, Polen KN, Hageman J, Meaney-Delman D, et al. Preventing transmission of Zika virus in labor and delivery settings through implementation of standard precautions - United States, 2016. MMWR Morb Mortal Wkly Rep 2016;65:290-2.

Pan American Health Organization. Zika virus infection. Washington, DC: PAHO; 2016. Available at: http://www.paho.org/hq/index.php?option=com_content&view=article&id=11585&Itemid=41688&lang=en. Retrieved March 30, 2016.

Parra-Saavedra M, Reefhuis J, Piraquive JP, Gilboa SM, Badell ML, Moore CA, et al. Serial head and brain imaging of 17 fetuses with confirmed Zika virus infection in Colombia, South America. Obstet Gynecol 2017;130:207-12. Available at: http://journals.lww.com/greenjournal/fulltext/2017/07000/Serial_Head_and_Brain_Imaging_of_17_Fetuses_With.29.aspx. Retrieved August 29, 2017. 

Petersen EE, Meaney-Delman D, Neblett-Fanfair R, Havers F, Oduyebo T, Hills SL, et al.   Update: interim guidance for preconception counseling and prevention of sexual transmission of Zika virus for persons with possible Zika virus exposure - United States, September 2016. MMWR Morb Mortal Wkly Rep 2016;65:1077-81.

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This Practice Advisory was developed by the American College of Obstetricians and Gynecologists and the Society for Maternal–Fetal Medicine in collaboration with Laura E. Riley, MD and R. Phillips Heine, MD.

A Practice Advisory is issued when information on an emergent clinical issue (eg, clinical study, scientific report, draft regulation) is released that requires an immediate or rapid response, particularly if it is anticipated that it will generate a multitude of inquiries. A Practice Advisory is a brief, focused statement issued within 24–48 hours of the release of this evolving information and constitutes ACOG clinical guidance. A Practice Advisory is issued only online for Fellows but may also be used by patients and the media. Practice Advisories are reviewed periodically for reaffirmation, revision, withdrawal, or incorporation into other ACOG guidelines.
This document reflects emerging clinical and scientific advances as of the date issued and is subject to change. The information should not be construed as dictating an exclusive course of treatment or procedure to be followed.


The American College of Obstetricians and Gynecologists (The College), a 501(c)(3) organization, is the nation's leading group of physicians providing health care for women. As a private, voluntary, nonprofit membership organization of more than 57,000 members, The College strongly advocates for quality health care for women, maintains the highest standards of clinical practice and continuing education of its members, promotes patient education, and increases awareness among its members and the public of the changing issues facing women’s health care. The American Congress of Obstetricians and Gynecologists (ACOG), a 501(c)(6) organization, is its companion organization. www.acog.org

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The American College of Obstetricians and Gynecologists (The College), a 501(c)(3) organization, 

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