Maternal pulse pressure at admission is a risk factor for fetal heart rate changes after initial dosing of a labor epidural: a retrospective cohort study

Objective To examine low maternal admission pulse pressure (PP) as a risk factor for new onset postepidural fetal heart rate (FHR) abnormalities. Study Design Retrospective cohort study of nulliparous, singleton, vertex-presenting women admitted to labor and delivery after 37 0/7 weeks that received an epidural during labor. Women with a low admission PP were compared with those with a normal admission PP. The primary outcome was new onset FHR abnormalities defined as recurrent late or prolonged FHR decelerations in the first hour after initial dosing of a labor epidural. Results New onset FHR abnormalities, defined as recurrent late decelerations and/or prolonged decelerations, occurred in 6% of subjects in the normal PP cohort compared with 27% in the low PP cohort (odds ratio, 5.6; 95% confidence interval, 2.1–14.3; P < .001). A multivariate logistic regression analysis generated an adjusted odds ratio of 28.9 (95% confidence interval, 3.7–221.4; P < .001). Conclusion New onset FHR abnormalities after initial labor epidural dosing occur more frequently in women with a low admission PP than those with a normal admission pulse. Admission PP appears to be a novel predictor of new onset postepidural FHR abnormalities.