Amniotic Band Sequence)

Uterine synechiae have been considered benign findings in pregnancy. Comparison of pregnancy outcomes between women with and without uterine synechiae in a large perinatal database shows that uterine synechiae are associated with significant increase in the risk of PROM, placental abruption, and cesarean delivery for malpresentation. The risks of placenta previa, fetal growth restriction, stillbirth, and preterm delivery were not significantly different. Amniotic band sequence results from in utero entrapment of fetal parts by fibrous bands, which leads to malformations that can affect multiple organ systems ranging from simple band constrictions to major craniofacial and visceral defects. There is typically an asymmetric distribution of these defects especially in the limbs. The cause of amniotic band sequence is unclear. The incidence varies from 1 in 1200 to 1 in 15,000 live births. Ultrasound diagnosis is based on a spectrum of features involving extremities, craniofacial region and trunk, may be isolated or in combination. Random anomalies that do not follow a pattern should lead to suspicion for amniotic band sequence. Demonstration of bands in not necessary for the diagnosis. Anomalies in extremities include absent digits or portions of limbs, swollen distal arm or leg resulting from constrictive amniotic bands. Craniofacial anomalies are facial cleft, asymmetric microphthalmia, severe nasal deformity, encephalocele. Trunk anomalies include severe spinal deformities, chest wall and abdominal wall defects such as ectopia cordis, gastroschisis-like bowel herniation, omphalocele-like liver herniation, and bladder exstrophy. The most extreme manifestation is body stalk anomaly. The incidence of chromosomal abnormalities or genetic syndromes is not increased. Prognosis and treatment depends on the severity of deformation. Body stalk anomaly is lethal. There is no increased risk of recurrence.