Intrauterine contraction parameters at baseline and following epidural and combined spinal-epidural analgesia: A repeated measures comparison.

OBJECTIVE: The effects of epidural and combined spinal-epidural analgesia on uterine contraction parameters are unclear, although as many as 80% of laboring women use neuraxial analgesia. We explored the effects of epidural and combined spinal-epidural analgesia on all uterine contraction parameters using a retrospective analysis of selected parturients, who required Intrauterine Pressure Catheter (IUPC) instrumentation for clinical management. Additionally, we analyzed the effects of parity, Pitocin dose, and mode of neuraxial anesthesia, i.e. epidural verses combined spinal-epidural on uterine contractility. DESIGN: Using a retrospective within and between repeated measure design we compared uterine contraction parameters at 4 time points (epochs): (1) baseline, (2) pre-epidural fluid bolus, (3) immediate and (4) secondary post-epidural/combined spinal-epidural analgesia to detect differences in contractility over time comparing two types of epidural interventions. METHODS: Eighteen healthy parturients at term gestation were admitted to the labor unit for induction, augmentation, or spontaneous labor. Contraction parameters including frequency, duration, peak intensity, resting intensity and duration, and Montevideo Units (MVUs) were collected using fetal monitor strip data with intrauterine pressure catheter (IUPC) instrumentation. FINDINGS: Parametric and non-parametric tests showed no significant differences within or between the two Epidural intervention groups for frequency, duration, peak intensity, resting intensity and duration, and MVUs at all epochs at the .05 alpha level. Compared with Nulliparous women, multiparous women had significantly lower contraction intensity and longer contraction duration. Based on multilevel modeling (MLM), neither Pitocin dose nor type of epidural intervention revealed significant differences on any contraction parameters. CONCLUSIONS: When parity, other demographic variables and Pitocin dose were statistically controlled, no uterine contraction parameter changed from baseline through 90 min following either epidural or combined spinal-epidural analgesia. Obstetrical care providers should consider the preciseness their contraction monitoring instrumentation and their clinical management preferences as well parity as before prescribing Pitocin after neuraxial analgesia intervention.