ADAM sequence and innocent amniotic band: manifestations of early amnion rupture

Thirteen placentas with early amnion rupture (EAR) are described. These placentas were characterized by the absence of amniotic epithelium on the fetal surface, presence of a slightly fibrotic small amniotic band (remnant) attaching to the umbilical cord at the placental end, and the presence of degenerated vernix squamous cells in the fibrous stroma of chorion and amnion. Eight fetuses had ADAM sequence. Six of these fetuses were miscarried between 16 and 28 weeks of gestation. Two affected infants were born alive at gestational ages of 29 and 39 weeks. Five infants were spared by ADAM sequence; two had the umbilical cord strangulated by an amniotic band and were delivered at 27 and 37 weeks. In the 3 infants unassociated with ADAM sequence or strangulation of the umbilical cord, their placentas were interpreted as having innocent amniotic band (IAB) and they were delivered between 32 and 40 weeks. The findings in this study support Torpin's hypothesis that ADAM sequence is a complication of EAR. This ADAM sequence due to simple EAR must be separated from the limb body wall malformation complex because visceral anomalies are uncommon in the former condition but are frequently seen in the latter. In this study the placental pathology of EAR was helpful in confirming the ADAM sequence in the fetus.