Amnioinfusion compared with expectant management in oligohydramnios with intact amnions in the second and early third trimesters

Introduction: Treatment of oligohydramnios in the mid-trimester is challenging, because of the high incidence of adverse perinatal outcomes mainly due to bronchopulmonary dysplasia. Antenatal amnioinfusion has been proposed as a possible treatment for oligohydramnios with intact amnions, but there are few relevant studies. This study aimed to evaluate the effectiveness of transabdominal amnioinfusion in the management of oligohydramnios without fetal lethal malformations in the second and early third trimesters. Material and Methods: It is a historical cohort study. A total of 79 patients diagnosed with oligohydramnios at 18-32 weeks gestation were enrolled. In the amnioinfusion group (n = 39), patients received transabdominal amnioinfusion with the assistance of real-time ultrasound guidance. In the expectant group (n = 41), patients were treated with 3000 mL of intravenous isotonic fluids daily. The perioperative complications and perinatal outcomes were analyzed. Results: Compared with the expectant group, the delivery latency was significantly prolonged, and the rate of cesarean delivery was significantly reduced in the amnioinfusion group (p < 0.05). Although the rate of intrauterine fetal death was significantly reduced, the incidence of spontaneous miscarriage, premature rupture of membranes (PROMs), and threatened preterm labor were significantly higher in the amnioinfusion group than in the expectant group (p < 0.05). There was no significant difference in terms of perinatal mortality (28.9% vs. 41.4%, p > 0.05). Multivariate logistic regression revealed that amnioinfusion (odds ratio [OR] 0.162, 95% confidence interval [CI] 0.04-0.61, p = 0.008) and gestational age at diagnosis (OR 0.185, 95% CI 0.04-0.73, p = 0.016) were independently associated with neonatal adverse outcomes. Further subgrouping showed that amnioinfusion significantly reduced the frequency of bronchopulmonary hypoplasia for patients <= 26 weeks (26.7% vs. 75.0%, p = 0.021). The rates of other neonatal complications were similar in both groups. Conclusions: Amnioinfusion has no significant effect on improving the perinatal mortality of oligohydramnios in the second and early third trimesters. It may lead to a relatively high rate of PROM and spontaneous abortion. However, amnioinfusion may significantly improve the latency period, the rate of cesarean delivery, and neonatal outcomes of oligohydramnios, especially for women <= 26 weeks with high risk of neonatal bronchopulmonary hypoplasia.