Expectant management for umbilical artery thrombosis in monochorionic diamniotic twin pregnancies: a case report

Thrombosis of one of the umbilical arteries is a rare complication of pregnancy and is associated with adverse pregnancy outcomes, including stillbirth and intrauterine growth restriction. Although extremely rare, umbilical artery thrombosis (UAT) in monochorionic diamniotic twins is difficult to diagnose prenatally and manage. UAT has a poor prognosis and is associated with an increased perinatal mortality rate. In most previous cases, emergency cesarean section was performed or intrauterine fetal death occurred at the time of UAT diagnosis.

Herein, we report an extremely rare case of sequential UAT in monochorionic diamniotic twins diagnosed via ultrasound at 29^+ 5 weeks of gestation in a 34-year-old woman. Following expectant management with intensive monitoring for 16 days, two healthy infants were delivered through an emergency cesarean section. UAT in both fetuses was confirmed by pathological examination. The mother and twins described in this case underwent long-term follow-up and are currently in good health without any complications.

Based on our experience, we suggest that expectant management should be undertaken as long as the mother and infants are stable on ultrasonographic scans and are closely monitored. When UAT is suspected, we believe that the best delivery time should be determined by considering complaints of unusual fetal movements, non-stress test evidence, gestational age, amniotic fluid volume, and blood flow in the umbilical artery, middle cerebral artery, and ductus venosus. Obstetricians should ensure that the patients and their families are clearly informed about all potential risks of expectant management for UAT.