Published In

EClinicalMedicine

Document Type

Article

Publication Date

6-2022

Subjects

Labour progress, Labour dystocia, Labour duration, Prolonged labour

Abstract

Background

Friedman's curve, despite acknowledged limitations, has greatly influenced labour management. Interventions to hasten birth are now ubiquitous, challenging the contemporary study of normal labour. Our primary purpose was to characterise normal active labour and pushing durations in a large, contemporary sample experiencing minimal intervention, stratified by parity, age, and body mass index (BMI).

Methods

This is a secondary analysis of the national, validated Midwives Alliance of North America 4·0 (MANA Stats) data registry (n = 75,243), prospectively collected between Jan 1, 2012 and Dec 31, 2018 to describe labour and birth in home and birth center settings where common obstetric interventions [i.e., oxytocin, planned cesarean] are not available. The MANA Stats cohort includes pregnant people who intended birth in these settings and prospectively collects labour and birth processes and outcomes regardless of where birth or postpartum care ultimately occurs. Survival curves were calculated to estimate labour duration percentiles (e.g. 10th, 50th, 90th, and others of interest), by parity and sub-stratified by age and BMI.

Findings

Compared to multiparous women (n = 32,882), nulliparous women (n = 15,331) had significantly longer active labour [e.g., median 7.5 vs. 3.3 h; 95th percentile 34.8 vs. 12.0 h] and significantly longer pushing phase [e.g., median 1.1 vs. 0.2 h; 95th percentile 5.5 vs. 1.1 h]. Among nulliparous women, maternal age >35 was associated with longer active first stage of labour and longer pushing phase, and BMI >30 kg/m² was associated with a longer active first stage of labour but a shorter pushing phase. Patterns among multiparous women were different, with those >35 years of age experiencing a slightly more rapid active labour and no difference in pushing duration, and those with BMI >30 kg/m² experiencing a slightly longer active labour but, similarly, no difference in pushing duration.

Interpretation

Nulliparous women had significantly longer active first stage and pushing phase durations than multiparous women, with further variation noted by age and by BMI. Contemporary US women with low-risk pregnancies who intended birth in settings absent common obstetric interventions and in spontaneous labour with a live, vertex, term, singleton, non-anomalous fetus experienced labour durations that were often longer than prior characterizations, particularly among nulliparous women. Results overcome prior and current sampling limitations to refine understanding of normal labour durations and time thresholds signaling ‘labour dystocia’.

Rights

Copyright (c) 2022 The Authors

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

DOI

10.1016/j.eclinm.2022.101447

Persistent Identifier

https://archives.pdx.edu/ds/psu/39760

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