Influence of oligohydramnios on preterm premature rupture of the membranes at 30 to 36 weeks' gestation.

OBJECTIVE

to evaluate the influence of initial oligohydramnios on the prognosis of women with preterm premature rupture of the membranes (PPROM) at 30 to 36 weeks' gestation.

METHODS

the Royal Alexandra Hospital ultrasound database was used to identify singleton pregnancies at 30 to 36 weeks' gestation with an ultrasound performed for confirmed PPROM from January 1992 to December 2006. Records were linked to the electronic provincial delivery record to perform a retrospective cohort study comparing the outcomes of pregnancies with an initial amniotic fluid index (AFI) < 5 cm with the outcomes of pregnancies with an AFI of 5 to 10 cm. Logistic and linear regression were used to analyze the association between binary outcome and explanatory variables.

RESULTS

the maternal and perinatal outcomes of 438 pregnancies were analyzed. Univariate analysis suggested statistically significant associations between initial oligohydramnios and decreased latency (P < 0.001), increased histologically proven chorioamnionitis (P = 0.01), neonatal length of stay in hospital (P = 0.002), and NICU (P = 0.003); however, after controlling for confounding variables (gestational age at delivery, parity, presentation, and antenatal antibiotic and corticosteroid administration), only latency remained significant (P = 0.004). No association was found between initial oligohydramnios and any other outcomes assessed, including mode of delivery, postpartum endometritis, maternal length of stay, non-reassuring fetal status, and neonatal morbidity and mortality.

CONCLUSION

initial oligohydramnios is associated with decreased latency in singleton pregnancies complicated by PPROM at 30 to 36 weeks' gestation; however, it does not appear to influence maternal or neonatal infectious morbidity, and it may not be useful to determine candidacy for expectant management or intentional delivery.