Contemporary Patterns of Spontaneous Labor With Normal Neonatal Outcomes

Abstract

Objective To use contemporary labor data to examine the labor patterns in a large, modern obstetric population in the United States. Methods Data were from the Consortium on Safe Labor, a multicenter retrospective study that abstracted detailed labor and delivery information from electronic medical records in 19 hospitals across the United States. A total of 62,415 parturients were selected who had a singleton term gestation, spontaneous onset of labor, vertex presentation, vaginal delivery, and a normal perinatal outcome. A repeated-measures analysis was used to construct average labor curves by parity. An interval-censored regression was used to estimate duration of labor stratified by cervical dilation at admission and centimeter by centimeter. Results Labor may take over 6 hours to progress from 4 to 5 cm and over 3 hours to progress from 5 to 6 cm of dilation. Nulliparas and multiparas appeared to progress at a similar pace before 6 cm. However, after 6 cm labor accelerated much faster in multiparas than in nulliparas. The 95th percentile of the 2nd stage of labor in nulliparas with and without epidural analgesia was 3.6 and 2.8 hours, respectively. A partogram for nulliparas is proposed. Conclusion In a large, contemporary population, the rate of cervical dilation accelerated after 6 cm and progress from 4 to 6 cm was far slower than previously described. Allowing labor to continue for a longer period before 6 cm of cervical dilation may reduce the rate of intrapartum and subsequent repeat cesarean deliveries in the United States.

Cervical dilatation patterns of ‘low‐risk’ women with spontaneous labour and normal perinatal outcomes: a systematic review

“…For nulliparous women the median cervical dilatation was 3.0–4.0 cm, with variable degrees of effacement, and for parous women the median cervical dilatation was 3.5–5.0 cm, with a considerable proportion of women with a well‐effaced cervix. Oxytocin augmentation varied from 0% (in a Chinese study)23 to 50% in a US study,7 for nulliparous women, and between 126 and 45%21 in two US study populations for parous women. Epidural analgesia use was restricted to the US studies for both parity groups 6, 7, 21…”

“…All of the studies provided data for nulliparous women ( n  = 43 148), whereas three studies provided data for parous women ( n  = 56 823) (OT Oladapo et al., unpubl. data) 6, 21. Nulliparous women had mean ages of 20.3–28.0 years and gestational ages at delivery of 39.3–39.8 weeks.…”

“…Of the 8785 citations obtained from the search strategies, 169 potentially eligible studies were identified for full‐text assessment (Figure 1). Seven observational studies conducted in the USA,6, 7, 21 China,22, 23 Japan,24 Nigeria (OT Oladapo et al., unpubl. data), and Uganda (OT Oladapo et al., unpubl.…”

“…Study populations were generally made up of the nationality where each study was conducted, except for studies in the USA 6, 7, 21. All of the studies provided data for nulliparous women ( n  = 43 148), whereas three studies provided data for parous women ( n  = 56 823) (OT Oladapo et al., unpubl.…”

“…Of the seven studies examining nulliparous women, four were considered to be at low risk of bias (OT Oladapo et al., unpubl. data),6, 21, 22 two at moderate risk of bias,7, 24 and one at high risk of bias 23. All three studies examining parous women were assessed to be at low risk of bias (OT Oladapo et al., unpubl.…”