Transabdominal amnioinfusion in oligohydramnios at term before induction of labor with intact membranes: a randomized clinical trial.

Abstract

Our purpose was to determine the effectiveness of transabdominal amnioinfusion before induction of labor in reducing the incidence of fetal distress in pregnancies with oligohydramnios at term. Between June 1991 and September 1994 primiparous women with ultrasonographic evidence of oligohydramnios at term, intact membranes, and unripe cervix (Bishop score < or = 6), candidates for induction of labor with cervical or vaginal prostaglandin E2 gel, were randomly selected to receive transabdominal amnioinfusion (amnioinfused group, n = 39) or to proceed with direct labor induction (control group, n = 40). Inclusion criteria were (1) singleton gestation, (2) vertex presentation, (3) ultrasonographic estimation of fetal weight > or = 2500 gm, and (4) reactive nonstress test. Fetoneonatal outcome variables were compared between the two groups. Statistical analysis used contingency tables, Student t test, or Wilcoxon rank-sum tests, where applicable. Amnioinfusion was successfully performed in 100% of the patients randomized for the procedure. The incidence of severely abnormal fetal heart rate tracings was significantly higher in the control than in the amnioinfused group (42% [17/33] vs 5% [2/37], relative risk 12.9, 95% confidence interval 2.4 to 56.4). The rate of cesarean sections performed for fetal distress was fivefold higher in the control group (25% [10/40] vs 5% [2/39], relative risk 4.9, 95% confidence interval 1.1 to 32.4). No bleeding complications or fetomaternal infectious morbidity were noticed. Transabdominal amnioinfusion is a safe, effective option for the prevention of fetal distress in pregnancies with oligohydramnios at term with intact membranes and unripe cervix.