Duration of Spontaneous Active Labor and Perinatal Outcomes Using Contemporary Labor Curves

Area of Science:

• Obstetrics and Gynecology
• Perinatal Medicine
• Maternal-Fetal Medicine

Background:

• Contemporary labor curves provide benchmarks for normal labor progression.
• Understanding deviations from these curves is crucial for identifying potential adverse outcomes.

Purpose of the Study:

• To evaluate the association between spontaneous active labor duration, defined by contemporary labor curves, and the risk of adverse maternal and neonatal outcomes.
• To assess the impact of labor duration exceeding established percentiles on cesarean delivery and chorioamnionitis.

Main Methods:

• Retrospective cohort study of nulliparous women (18-44 years) with singleton, cephalic gestations ≥37 weeks in spontaneous labor.
• Subjects were stratified into subgroups based on active labor duration (6-10 cm) relative to the median, median-95th, and >95th percentiles of contemporary labor curves.
• Logistic regression was used to analyze the association with cesarean delivery, chorioamnionitis, and other adverse outcomes.

Main Results:

• Women with active labor duration in the median-95th percentile and >95th percentile subgroups had significantly higher odds of cesarean delivery (aOR 3.1 and 6.8, respectively) compared to those below the median.
• An increased odds of chorioamnionitis was observed in the median-95th percentile subgroup (aOR 2.5).

Conclusions:

• Active labor duration exceeding contemporary median percentiles is associated with significantly increased risks of cesarean delivery and chorioamnionitis.
• These findings highlight the importance of utilizing updated labor curves for risk assessment and management during spontaneous labor.