Constriction bands and limb reduction defects in two newborns with fetal ultrasound evidence for vascular disruption.
Most structural anomalies attributed to vascular disruption have been inferred, though not proven, to be the result of disruptive events in utero. We report on 2 pregnancies with ultrasound evidence of disruptive events resulting in terminal limb "reduction" defects with constriction bands and other anomalies. In the first patient a fetal ultrasound study at 12 weeks post-LMP demonstrated a monochorionic (MC) twin pregnancy with a nonviable co-twin and no evidence of amniotic bands. At birth, there was a left cleft lip and palate, and terminal limb "reduction" defects with ring constrictions of the left hand and both feet. In the second patient, a routine fetal ultrasound study at 18 weeks post-LMP identified a subhepatic cyst which subsequently resolved. Fetal ultrasound examination and neonatal computed tomography (CT) scan of the liver were consistent with a hepatic infarct due to emboli from the umbilical vein. At birth, patient 2 had acrosyndactyly of the left hand with ring constrictions of the digits and reduction of the left big toe. There was no evidence of abnormal amnion. Postnatal development has been normal in both cases. We present ultrasound evidence supporting the hypothesis that vascular disruption from death of a co-twin or from in utero embolic infarcts can cause: 1) terminal limb "reduction" defects and possibly cleft lip and palate; and 2) ring constrictions similar to those of "amniotic band disruption sequence" in the absence of an abnormal amnion. Serial pregnancy ultrasound studies are recommended for evaluation of the development of fetal structural anomalies following ultrasound evidence of a disruptive event in utero.