Uterine contractions might increase heart preload in the recipient fetus in early‐onset twin–twin transfusion syndrome: an ultrasound assessment

Abstract

Uterine contractions (UC) in twin pregnancy are often experienced, yet the effects of UC in twin-twin transfusion syndrome (TTTS) remain to be clarified. The recipient heart preload condition and the effects of UC were evaluated and the final objective was to clarify the effects of tocolysis. Firstly, the preload indexes (PLIs) and cardiothoracic area ratios (CTARs) were analyzed on both fetuses of 10 TTTS cases, aged from 14 to 28 gestational weeks in stage III/IV cases for evaluating the preload condition. Then, the PLIs in the presence and absence of UC in the recipient fetuses were determined to evaluate the difference. The PLIs of the recipient and the donor fetuses were 0.78 +/- 0.34 (n = 163) and 0.35 +/- 0.13 (n = 71) respectively. The CTARs were 30.2 +/- 6.1 (n = 62) and 23.4 +/- 5.4 (n = 62) respectively. The PLIs in the absence and presence of UC in the recipient fetuses were 0.69 +/- 0.29 and 0.99 +/- 0.38 (n = 35). All above comparisons showed highly significant differences (p < 0.0001). The recipient fetuses have signs of cardiac dilatation and a high-preload condition. UC transiently further raises high-preload conditions of the recipient fetus. Thus, tocolysis may be necessary for management in cases of early-onset severe TTTS.