Intrauterine Growth Restriction (IUGR)

Singleton white pregnancy presents with estimated fetal weight and abdominal circumference <10th percentile on initial anatomic ultrasound. Mother reports h/o HTN, GDM, thrombophilia, smoking, cocaine use, and IUGR affecting a previous pregnancy. Current pregnancy complicated by vaginal bleeding during 1st trimester and recent febrile illness. Fundal height less than predicted by current weeks gestational age (WGA).

  • LMP, initial dating ultrasound, and calculated due date reviewed and found to be accurate

  • Labs

    • Rule out fetal aneuploidy and obtain cell free DNA (cfDNA) if initial testing is non-reassuring

    • Suspicion of rubella, varicella, CMV, toxoplasmosis infection: Evaluate for maternal seropositivity

    • Consider evaluation for antiphospholipid syndrome

  • Imaging

    • Obtain biophysical profile (BPP)

    • Detailed fetal anatomic survey reveals abnormal fetal anatomy, umbilical cord structure, placental structure

    • Serial anatomic surveys show

      • Fetus failing to progress along normal growth curve

      • Reduced abdominal circumference growth velocity

  • Continued management

    • Monitor with once weekly NST and growth scan; consider reducing frequency to once every two weeks if results are reassuring

    • Abnormal BPP: Refer for umbilical artery Doppler velocimetry; consider administering antenatal corticosteroids and delivering immediately for

      • Abnormal ductus venosus

      • 32+ WGA with reversed diastolic flow

      • 34+ WGA with absent diastolic flow

    • Plan for induction no later than 39 WGA and send arterial and venous cord blood samples s/p delivery

  • Pt counseled that with the exception of stopping smoking and cocaine use, there is nothing she can do to alter fetal growth pattern

Notes

  • Normal vs. abnormal growth

    • Twin, triplet, etc. gestations and (often) non-white babies in the U.S. follow non-standard growth curves

    • IUGR is technically defined as <10th percentile, but fetuses in the 5th to 10th percentile with no other abnormalities are more likely to be constitutionally small vs. growth restricted

    • True growth restriction is more likely in cases with an abnormal head circumference:abdominal circumference ratio

  • Growth restricted fetuses

    • Potential etiologies include genetic abnormalities, placental insufficiency, infectious diseases, maternal health conditions, and exposure to teratogens and/or other noxious substances

    • At greater risk perinatal morbidity and mortality

  • Intervention

    • Cell free DNA allows for fetal karyotyping

    • Early delivery based on Doppler velocimetry results may reduce stillbirths while increasing neonatal deaths. Long term outcomes may also not be affected. Research is ongoing.