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Updated Guidance Regarding Fetal Growth Restriction

  • Practice Advisory PA
  • September 2020

This Practice Advisory is provided to update two joint American College of Obstetricians and Gynecologists (ACOG) and Society for Maternal-Fetal Medicine (SMFM) guidance documents: Practice Bulletin No. 204, Fetal Growth Restriction 1 and Committee Opinion No. 764, Medically Indicated Late-Preterm and Early-Term Deliveries 2 . This update addresses three specific aspects:

  • the definition of fetal growth restriction,
  • the timing of delivery in the setting of isolated fetal growth restriction, and
  • the timing of delivery for fetal growth restriction with absent or reversed end-diastolic flow.

These updates are provided to align the Practice Bulletin and Committee Opinion with the SMFM Consult Series No. 52, Diagnosis and Management of Fetal Growth Restriction 3.

Definition of Fetal Growth Restriction

The current Practice Bulletin defines fetal growth restriction as an estimated fetal weight less than the 10th percentile for gestational age. Although uncommon in isolation, an abdominal circumference less than the 10th percentile for gestational age also may be used to define fetal growth restriction. Thus, fetal growth restriction may be defined as an estimated fetal weight or abdominal circumference less than the 10th percentile for gestational age.

Timing of Delivery (Table 1)

Isolated fetal growth restriction with reassuring umbilical artery assessment:

The current Practice Bulletin and Committee Opinion suggest delivery at 38 0/7–39 6/7 weeks of gestation in cases of isolated fetal growth restriction with reassuring umbilical artery Doppler assessment. The SMFM Consult Series further categorizes isolated fetal growth restriction based on the percentile of estimated fetal weight, recommending delivery at 38 to 39 weeks for isolated fetal growth restriction with estimated fetal weight between the 3rd and 10th percentiles and delivery at 37 weeks of gestation for severe fetal growth restriction with estimated fetal weight less than the 3rd percentile. Thus, for cases of isolated fetal growth restriction with an estimated fetal weight less than the 3rd percentile, delivery at 37 0/7 weeks of gestation or at diagnosis if diagnosed later is now recommended.

Fetal growth restriction with absent or reversed end-diastolic flow:

In order to align with the SMFM Consult Series, the timing of delivery is being updated to recommend delivery at 33 0/7–34 0/7 weeks of gestation or at diagnosis if diagnosed later for fetal growth restriction with absent end-diastolic flow, and at 30 0/7–32 0/7 weeks of gestation or at diagnosis if diagnosed later for fetal growth restriction with reversed end-diastolic flow.

Table 1. Summary of Timing of Delivery Recommendation Updates

 Criterion

 Committee Opinion No. 764

Updated Recommendations

Otherwise uncomplicated, no concurrent findings

38 0/7–39 6/7 weeks of gestation

38 0/7 – 39 0/7 weeks of gestation (EFW between 3rd – 10th percentile)

37 0/7 weeks of gestation or at diagnosis if diagnosed later (EFW < 3rd percentile)

Abnormal UA dopplers: decreased end diastolic flow without absent end-diastolic flow

Consider at 37 0/7 weeks of gestation or at diagnosis if diagnosed later

37 0/7 weeks of gestation or at diagnosis if diagnosed later

Abnormal UA dopplers: absent end-diastolic flow

Consider at 34 0/7 weeks of gestation or at diagnosis if diagnosed later

33 0/7–34 0/7 weeks of gestation or at diagnosis if diagnosed later*

Abnormal UA dopplers: reversed end-diastolic flow

Consider at 32 0/7 weeks of gestation or at diagnosis if diagnosed later

30 0/7–32 0/7 weeks of gestation or at diagnosis if diagnosed later *

Concurrent conditions (oligohydramnios, maternal comorbidity [eg, preeclampsia, chronic hypertension])

34 0/7–37 6/7 weeks of gestation

No changes

Abbreviations: EFW, estimated fetal weight; S/D, systolic/diastolic; UA, umbilical artery.

*Consultation with maternal-fetal medicine subspecialist is recommended.


References

  1. Fetal growth restriction. ACOG Practice Bulletin No. 204. American College of Obstetricians and Gynecologists. Obstet Gynecol 2019;133:e97-109.
    Article Locations:
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  2. Medically indicated late-preterm and early-term deliveries. ACOG Committee Opinion No. 764. American College of Obstetricians and Gynecologists. Obstet Gynecol 2019;133:e151-5.
    Article Locations:
    Article Location
  3. Society for Maternal-Fetal Medicine. SMFM Consult Series #52: diagnosis and management of fetal growth restriction. Washington, DC: SMFM; 2020. Available at: https://www.smfm.org/publications/289-smfm-consult-series-52-diagnosis-and-management-of-fetal-growth-restriction.. Retrieved September 10, 2020.
    Article Locations:
    Article Location

This Practice Advisory was developed by the American College of Obstetricians and Gynecologists in collaboration with Alison G. Cahill, MD; Aaron B. Caughey, MD, PhD; Cynthia Gyamfi-Bannerman, MD, MSc; Anjali J. Kaimal, MD, MAS; and Mark Turrentine, MD.


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