358: Declining NICU admissions in uncomplicated fetal growth restriction following adoption of ACOG/SMFM practice guidelines

Abstract

progression. We tested the hypothesis that women with cHTN are more likely to have a longer first stage of labor. STUDY DESIGN: This was a retrospective cohort study of all women with singleton term pregnancies that reached 10 cm cervical dilation at a tertiary care center from 2004 to 2014. Labor curves were compared between patients with and without cHTN and was then stratified by labor type (induction vs spontaneous) and by need for anti-hypertensive agent during pregnancy. T-tests & Mann Whitney U tests were used for continuous variables and chi-square/Fisher's exact tests for categorical variables. Interval-censored regression was used to estimate median times for cervical change. RESULTS: Of the 21,841 patients with term pregnancies that reached 10 cm cervical dilation, 746 (3.4%) had cHTN. Compared to those without cHTN, patients with cHTN were more likely to be 35 or older, obese, African-American, diabetic, have a prior cesarean, undergo induction, and receive oxytocin augmentation. Patients with cHTN were less likely to nulliparous. cHTN patients were more likely to have a longer first stage of labor with a longer time to dilate from 4 to 10 cm (adjusted median 5.86 vs 4.67 hours, p< .01), even after adjusting for confounders. After stratifying by antihypertensive use, there was no difference in labor progression between patients with and without antihypertensive use. CONCLUSION: Women with cHTN had longer first stages of labor than women without cHTN, even after adjusting for relevant confounders and accounting for induction of labor. As the number of pregnant women with cHTN increases, understanding the natural history of labor in this population is essential to the modern practice of obstetrics.