Prophylactic amnioinfusion for intrapartum oligohydramnios: a meta-analysis of randomized controlled trials

To evaluate the effectiveness of intrapartum prophylactic amnioinfusion in pregnancies complicated by oligohydramnios.

Randomized controlled trials of prophylactic amnioinfusion in women with oligohydramnios were identified using computerized databases, index reviews, and references cited in original studies and review articles.

We evaluated, abstracted data from, and analyzed randomized studies of prophylactic intrapartum amnioinfusion in women with oligohydramnios. In every study the group allocation was based exclusively on presence of oligohydramnios. Only published studies with clearly documented outcome data were included. The quality of each trial was evaluated for methodology, inclusion and exclusion criteria, adequacy of randomization, amnioinfusion protocols, definition of outcomes, and statistical analyses. The trials were evaluated concerning cesarean deliveries for fetal heart rate (FHR) abnormalities, overall cesarean rates, acidemia at birth, intrapartum fetal heart rate abnormalities, Apgar scores under 7 at 5 minutes, and postpartum endometritis.

Thirty-five studies were identified, of which 14 met the inclusion criteria for this systematic review. They included 1533 patients, 793 in the amnioinfusion group, and 740 controls. Odds ratios (OR) with their 95% confidence intervals (CI) for each outcome were calculated. We calculated an estimate of the OR and risk difference for dichotomous outcomes using random and fixed-effects models. A test of homogeneity was done across studies. Women with oligohydramnios who received intrapartum amnioinfusion had lower incidence of cesarean for FHR abnormalities (OR 0.23; 95% CI 0.15, 0.35). Intrapartum amnioinfusion also was associated with lower overall rates of cesarean deliveries (OR 0.52; 95% CI 0.40, 0. 68), acidemia at birth (OR 0.40; 95% CI 0.30, 0.55), FHR abnormalities during labor (OR 0.24; 95% CI 0.17, 0.34), and Apgar scores under 7 at 5 minutes (OR 0.52; 95% CI 0.29, 0.91). Postpartum endometritis rates were similar among the study groups.

In the presence of oligohydramnios, prophylactic intrapartum amnioinfusion significantly improves neonatal outcome and lessens the rate of cesarean delivery, without increasing the rate of postpartum endometritis.