Umbilical Artery Hypoplasia in Twin‐Twin Transfusion Syndrome Complicated by Discordant Umbilical Artery Doppler Findings in the Donor Twin

Abstract

etal Doppler assessment is a useful tool in diagnosing and staging monochorionic twins complicated by twin-twin transfusion syndrome (TTTS). 1Umbilical artery absent or reversed end-diastolic velocity (UA-AREDV) is a poor prognostic factor in TTTS 2,3 and is associated with increased risk of in utero fetal death of the donor twin. 4 The etiology of donor twin UA-AREDV has primarily been attributed to 2 placental factors: unequal individual placental territories and the presence of arterioarterial anastomoses.5 However, umbilical artery (UA) hypoplasia, which can result in UA-AREDV, has not to our knowledge been reported in association with TTTS. We present a case with donor twin umbilical artery absent enddiastolic velocity (UA-AEDV) caused by a hypoplastic UA, with emphasis on the diagnostic and management challenges associated with discordant UA Doppler findings in the setting of TTTS. Case ReportIn vitro fertilization with assisted hatching and implantation of 3 embryos resulted in a monochorionic diamniotic twin gestation in a 31-year-old primiparous woman. At 15 weeks 3 days, sonographic findings for twin B were notable for a maximum vertical amniotic fluid pocket (MVP) of 1 cm and persistent AEDV identified in a UA. However, repeat Doppler examinations performed at 16 weeks 6 days and 18 weeks showed normal UA diastolic flow. Umbilical artery AEDV was identified again in twin B at 18 weeks 2 days, at which time a diagnosis of Quintero stage 3 atypical donor TTTS was made. 1 Twin A, the recipient twin, had an estimated fetal weight of 281 g with an MVP of 9.7 cm. Twin B, the donor, weighed 234 g, accounting for a 17% growth discordance, with an MVP of 1.0 cm. A small bladder was visible in twin B. Aside from