First stage of labour duration and associated risk of adverse neonatal outcomes

Abstract

Prior evidence evaluating the benefits and harms of expectant labour duration during active first stage is inconclusive regarding potential consequences for the neonate. Population-based cohort study in Stockholm-Gotland region, Sweden, including 46,040 women (Robson 1), between October 1st, 2008 and June 15th, 2020. Modified Poisson regression was used for the association between active first stage of labour duration and adverse neonatal outcomes. 94.2% experienced a delivery with normal neonatal outcomes. Absolute risk for severe outcomes increased from 1.9 to 3.0%, moderate outcomes increased from 2.8 to 6.2% (> 10.1 h). Compared to the reference, (< 5.1 h; median), the adjusted relative risk (aRR) of severe neonatal outcome significantly increased beyond 10.1 h (> 90th percentile) (aRR 1.53, 95% CI 1.26, 1.87), for moderate neonatal outcome the aRR began to slowly increase beyond 5.1 h (≥ 50 percentile; aRR 1.40, 95% CI 1.24, 1.58). Mediation analysis indicate that most of the association was due to a longer active first stage of labour, 13% (severe neonatal outcomes) and 20% (moderate neonatal outcomes) of the risk was mediated (indirect effect) by longer second stage of labour duration. We report an association between increasing active first stage duration and increased risk of adverse neonatal outcomes. We did not observe a clear labour duration risk threshold.

Labor patterns of spontaneous first-stage labor in Chinese women with normal neonatal outcomes

“…Consistent with previous study [ 23 ], our findings suggested that nulliparous women with complicated outcomes experienced a longer progression of the first stage compared to those without complicated outcomes. Additionally, our study found that nulliparous women in the target population had a longer duration at the 95th centile compared to nulliparous women without complicated outcomes, which is in line with findings from Lundborg et al [ 10 ]. However, the differences in duration at the 95th centile in our study were shorter than those reported in Lundborg’s study (10 minutes vs. 2 hours).…”