Umbilical cord collision in the first trimester in a monoamniotic twin pregnancy – does it really matter?

Abstract

In the first ultrasound scan there were no abnormalities in twin I. In contrast, in twin II a vascular resistance in the umbilical artery was at the upper limit for the gestational age. Five days later, decreased vascular resistance in the middle cerebral artery, which fluctuated at the lower limit, was noticed in twin II. After the next four days, PI in the middle cerebral artery decreased below the lower limit and tricuspid regurgitation appeared. In twin I the vascular resistance in the umbilical artery increased and remained at the upper limit of the reference ranges. Cardiotocographic records did not reveal signs of fetal distress. After a week the signs of brain sparing effect were visible in both fetuses. However, twin II showed features of umbilical cord clamping in the form of abnormal blood flow waveforms in the umbilical artery („notch”). Therefore, despite the absence of signs of fetal distress in CTG in monochorionic monoamniotic twins with growth discordance of 20% and exponents of periodical clamping of the umbilical cord in twin II at 34 weeks, the decision to perform a caesarean section was made. The patient gave birth to two daughters (twin I: weight 1780g, Ap 10, pH 7.39, 7.40, BE -3.0, -2.6, and twin II: weight 1860g, Ap 10, pH 7.29, 7.35, BE -1.4, -2.4). During the delivery the umbilical cords collision was found at the region close to the body of twins. This case presents the possibility of using ultrasound and Doppler in the early diagnosis, monitoring and surveillance of pregnancies complicated by umbilical cords collision in monochorionic monoamniotic twins from the first trimester. Application of these methods allowed a safe monitoring of the fetuses and the identification of the onset of the cords collision. This in turn allowed the achievement of fetal maturity at 34 weeks, when both the risk of death and neonatal morbidity are significantly minimized. The use of Doppler blood flow velocimetry allowed the diagnosis of umbilical cords tightening before there were any signs of cardiac dysfunction in the CTG. This enabled to determine the most favorable, earlier time for delivery. The paper presents diagnostic management and surveillance in monochorionic monoamniotic pregnancy complicated by umbilical cord collision since the early pregnancy.