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New Prenatal Blood Test Promising

November 20, 2012

Washington, DC -- A new noninvasive blood test that measures cell free fetal DNA (cffDNA) to screen for three common genetic disorders early in pregnancy is extremely promising, according to a new Committee Opinion issued jointly today by The American College of Obstetricians and Gynecologists (The College) and the Society for Maternal-Fetal Medicine (SMFM). However, cffDNA testing should be limited to pregnant women at increased risk for common chromosomal abnormalities until further research is available.

Cell free fetal DNA uses a sample of a pregnant woman’s blood to screen for three of the most common genetic disorders in the fetus: trisomy 13 (Patau syndrome), trisomy 18 (Edwards syndrome), and trisomy 21 (Down syndrome). The screening test can be done as early as the 10th week of pregnancy, and test results can be available in about one week. Although cffDNA is not a diagnostic test, it is highly accurate. Women with positive cffDNA test results should be referred for genetic counseling and offered invasive prenatal testing (amniocentesis or chorionic villus sampling) to confirm the diagnosis. The downside to the cffDNA test is that it screens for only three genetic disorders and still requires an invasive procedure to confirm a positive test result. It can also fail to identify one of these genetic disorders or fail to obtain any result at all.

For now, The College and SMFM both say that cffDNA testing can be offered to pregnant women at increased risk for trisomy 13, 18, or 21. Women age 35 and older, women with a history of a child with trisomy, and women carrying a fetus that shows abnormalities on an ultrasound are at increased risk. The cffDNA test should not be offered to low-risk women or women carrying multiple fetuses because it has not been sufficiently tested in these groups.

Committee Opinion #545 “Noninvasive Prenatal Testing for Fetal Aneuploidy” is published in the December 2012 issue of Obstetrics & Gynecology.

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Other recommendations issued in this month’s Obstetrics & Gynecology:

Practice Bulletin #132 “Antiphospholipid Syndrome” (Revised)
ABSTRACT: Antiphospholipid syndrome (APS) is an autoimmune disorder defined by the presence of characteristic clinical features and specified levels of circulating antiphospholipid antibodies (Box 1 and Box 2). Diagnosis requires that at least one clinical and one laboratory criterion are met. Because approximately 70% of individuals with APS are female (1), it is reasonably prevalent among women of reproductive age. Antiphospholipid antibodies are a diverse group of antibodies with specificity for binding to negatively charged phospholipids on cell surfaces. Despite the prevalence and clinical significance of APS, there is controversy about the indications for and types of antiphospholipid tests that should be performed in order to diagnose the condition. Much of the debate results from a lack of well-designed and controlled studies on the diagnosis and management of APS. The purpose of this document is to evaluate the data for diagnosis and treatment of APS.

Committee Opinion #543 “Timing of Umbilical Cord Clamping After Birth” (NEW!)
ABSTRACT: The optimal timing for clamping the umbilical cord after birth has been a subject of controversy and debate. Although many randomized controlled trials in term and preterm infants have evaluated the benefits of delayed umbilical cord clamping versus immediate umbilical cord clamping, the ideal timing for cord clamping has yet to be established. Several systematic reviews have suggested that clamping the umbilical cord in all births should be delayed for at least 30–60 seconds, with the infant maintained at or below the level of the placenta because of the associated neonatal benefits, including increased blood volume, reduced need for blood transfusion, decreased incidence of intracranial hemorrhage in preterm infants, and lower frequency of iron deficiency anemia in term infants. Evidence exists to support delayed umbilical cord clamping in preterm infants, when feasible. The single most important clinical benefit for preterm infants is the possibility for a nearly 50% reduction in intraventricular hemorrhage. However, currently, evidence is insufficient to confirm or refute the potential for benefits from delayed umbilical cord clamping in term infants, especially in settings with rich resources.

Committee Opinion #544 “Over-the-Counter Access to Oral Contraceptives” (NEW!)
ABSTRACT: Unintended pregnancy remains a major public health problem in the United States. Access and cost issues are common reasons why women either do not use contraception or have gaps in use. A potential way to improve contraceptive access and use, and possibly decrease unintended pregnancy rates, is to allow over-the-counter access to oral contraceptives (OCs). Screening for cervical cancer or sexually transmitted infections is not medically required to provide hormonal contraception. Concerns include payment for pharmacist services, payment for over-the-counter OCs by insurers, and the possibility of pharmacists inappropriately refusing to provide OCs. Weighing the risks versus the benefits based on currently available data, OCs should be available over-the-counter. Women should self-screen for most contraindications to OCs using checklists.

Committee Opinion #546 “Tracking and Reminder Systems” (Revised)
ABSTRACT: An accurate and effective tracking or reminder system is useful for the modern practice of obstetrics and gynecology. Practices should not rely solely on the patient to complete all ordered studies and to follow up on health care provider recommendations. Health care providers should encourage their patients to complete studies believed essential for patient care within an acceptable time frame. Each office should establish a simple, reliable tracking and reminder system to facilitate communication, improve patient safety and quality of care, and minimize missed or delayed diagnoses.

Committee Opinion #547 “Health Care for Women in the Military and Women Veterans” (NEW!)
ABSTRACT: Military service is associated with unique risks to women’s reproductive health. As increasing numbers of women are serving in the military, and a greater proportion of United States Veterans are women, it is essential that obstetrician–-gynecologists are aware of and well prepared to address the unique health care needs of this demographic group. Obstetrician–-gynecologists should ask about women’s military service, know the Veteran status of their patients, and be aware of high prevalence problems (eg, posttraumatic stress disorder, intimate partner violence, and military sexual trauma) that can threaten the health and well-being of these women. Additional research examining the effect of military and Veteran status on reproductive health is needed to guide the care for this population. Moreover, partnerships between academic departments of obstetrics and gynecology and local branches of the Veterans Health Administration are encouraged as a means of optimizing the provision of comprehensive health care to this unique group of women.

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 approximately 56,000 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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