Factors associated with higher oxytocin requirements in labor

Abstract

Objective: To identify clinical characteristics associated with high maximum oxytocin doses in women who achieve complete cervical dilation.

Methods: A retrospective nested case-control study was performed within a cohort of all term women at a single center between 2004 and 2008 who reached the second stage of labor. Cases were defined as women who had a maximum oxytocin dose during labor >20 mu/min, while women in the control group had a maximum oxytocin dose during labor of ≤20 mu/min. Exclusion criteria included no oxytocin administration during labor, multiple gestations, major fetal anomalies, nonvertex presentation, and prior cesarean delivery. Multiple maternal, fetal, and labor factors were evaluated with univariable analysis and multivariable logistic regression.

Results: Maximum oxytocin doses >20 mu/min were administered to 108 women (3.6%), while 2864 women received doses ≤20 mu/min. Factors associated with higher maximum oxytocin dose after adjusting for relevant confounders included maternal diabetes, birthweight >4000 g, intrapartum fever, administration of magnesium, and induction of labor.

Conclusions: Few women who achieve complete cervical dilation require high doses of oxytocin. We identified maternal, fetal and labor factors that characterize this group of parturients.

• Labor augmentation
• labor induction
• labor management

Declaration of interest

Dr. Frey is supported by a training grant from the NICHD T32 grant (5 T32 HD055172-04) and this publication was supported by the Washington University CTSA grant (UL1 TR000448).

Dr. Cahill is a Robert Wood Johnson Foundation Physician Faculty Scholar, which partially supports this work.