EP17.74: Antenatal Doppler surveillance of third trimester diagnosis of amniotic band sequence prevents adverse outcomes: a case report

Amniotic band sequence or syndrome (ABS), a rare condition occurring in 1:1200-1:1500 live births, results from amnion disruption in-utero. The clinical manifestations of ABS range from tethering, constriction or amputation of fetal limbs, craniofacial or other body parts. Although ABS is commonly diagnosed in the first and second trimester, there have been rare reports of ABS in the third trimester diagnosed postnatally with adverse outcomes of stillbirth due to constriction of the umbilical cord. This is a case of late third trimester prenatal diagnosis of ABS with a successful live birth at 36 weeks and 5 days' gestational age (GA). A 27-year-old primigravid woman with BMI of greater than 30, had regular prenatal care that was established at 7 weeks 2 days with dating confirmation by 2D sonography, a normal 12-week nuchal translucency, and normal genetic serum screening. During second trimester fetal anatomical survey by 2D and 3D ultrasonography, she was diagnosed with 2-vessel umbilical cord (single left umbilical artery), and moderate to large size fibroid uterus that remained stable during pregnancy. A third trimester antenatal fetal surveillance and sonographic growth assessment visit at 35 weeks 4 days diagnosed polyhydramnios and multiple thin fibrous amniotic bands close to fetoplacental surface, traversing from placental cord insertion site across amniotic cavity and partially covering fetal hands and face. Fetal face and all four extremities were freely moving with no restriction from the bands. Patient was monitored with frequent non-stress tests, biophysical profile testing and umbilical artery (UA) Doppler assessments. At 36 weeks and 5 days GA, UA Doppler waveform was noted to have notching suggestive of umbilical arterial compression prompting delivery as it was also preceded by maternal perception of decreased fetal movements. Close fetal surveillance with UA Doppler waveform in 3rd trimester for ABS can prevent stillbirth and improve outcomes.