Abstract
Objective To estimate the effect of oligohydramnios on fetal heart rate (FHR) patterns in patients
undergoing induction of labor (IOL) at term.
Study Design Secondary analysis of a prospective cohort study of consecutive term, singleton deliveries
from 2010 to 2015. We included all patients who underwent IOL. Our primary outcomes
were electronic fetal monitoring (EFM) characteristics in the 2 hours preceding delivery.
Outcomes were compared between those induced with oligohydramnios and those induced
without a diagnosis of oligohydramnios. Our secondary outcome was composite neonatal
morbidity. Logistic regression was used to control for confounders.
Results Of 3,787 patients who underwent IOL, 147 had a diagnosis of oligohydramnios and 3,640
were included in the no oligohydramnios group. There was no significant difference
in EFM characteristics between the two groups. There was no difference in composite
neonatal morbidity. In patients with oligohydramnios, EFM patterns with baseline tachycardia
for 30 minutes or greater were significantly associated with composite neonatal morbidity
(31.3 vs. 5.3% adjusted odds ratio 8.63, 95% confidence interval 2.18, 34.1]).
Conclusion Term patients undergoing IOL with oligohydramnios had EFM patterns that did not differ
from their induced peers.
Keywords
electronic fetal monitoring - fetal heart rate - induction of labor - oligohydramnios
