Fetal hemodynamic changes following maternal betamethasone administration in monochorionic twin pregnancies featuring one twin with selective growth restriction and abnormal umbilical artery Doppler

Abstract

To evaluate fetal hemodynamic changes following maternal betamethasone administration in monochorionic twin pregnancies featuring one twin with selective intrauterine growth restriction (sIUGR) and absence of end-diastolic velocity in umbilical artery (UA) Doppler. sIUGR was defined as fetal weight below the 10th percentile in one twin and inter-twin birth weight discordance >25%. The results of Doppler examinations including UA, middle cerebral artery (MCA) and ductus venosus directly prior to (D0), at 24 h (D1) and 48 h (D2) after administration of the first dose of betamethasone were recorded. Cerebral-placenta ratio was defined as MCA pulsatility index (PI) divided by UA-PI. In four (20%) of the 20 cases, the UA Doppler of the growth-restricted twin returned to positive end-diastolic velocity after betamethasone administration. The UA-PI and MCA-PI of the sIUGR twin changed significantly after betamethasone administration: UA-PI was decreased at D1, the MCA-PI was reduced at both D1 and D2, and the cerebral-placenta ratio was not altered after betamethasone administration in the sIUGR twin. The hemodynamic changes after betamethasone administration were different between the two monochorionic twin fetuses where one presented with sIUGR and absence of UA end-diastolic velocity. The etiology of a low rate of return of end-diastolic velocity in the sIUGR twin needs further evaluation.