Maternal and perinatal outcomes of prolonged second stage of labour: a historical cohort study of over 51,000 women

Abstract

Background Prolonged second stage of labour has been associated with adverse maternal and perinatal outcomes. The maximum length of the second stage from full dilatation to birth of the baby remains controversial. Our aim was to determine whether extending second stage of labour was associated with adverse maternal and perinatal outcomes. Methods A retrospective cohort study was conducted using routinely collected hospital data from 51592 births in Aberdeen Maternity Hospital between 2000 and 2016. The hospital followed the local guidance of allowing second stage of labour to extend by an hour compared to national guidelines since 2008 (nulliparous and parous). The increasing duration of second stage of labour was the exposure. Baseline characteristics, maternal and perinatal outcomes were compared between women who had a second stage labour of (a) ≤ 3 h and (b) > 3 h duration for nulliparous women; and (a) ≤ 2 h or (b) > 2 h for parous women. An additional model was run that treated the duration of second stage of labour as a continuous variable (measured in hours). All the adjusted models accounted for: age, BMI, smoking status, deprivation category, induced birth, epidural, oxytocin, gestational age, baby birthweight, mode of birth and parity (only for the final model). Results Each hourly increase in the second stage of labour was associated with an increased risk of obstetric anal sphincter injury (aOR 1.21 95% CI 1.16,1.25), having an episiotomy (aOR 1.48 95% CI 1.45, 1.52) and postpartum haemorrhage (aOR 1.27 95% CI 1.25, 1.30). The rates of caesarean and forceps delivery also increased when second stage duration increased (aOR 2.60 95% CI 2.50, 2.70, and aOR 2.44 95% CI 2.38, 2.51, respectively.) Overall adverse perinatal outcomes were not found to change significantly with duration of second stage on multivariate analysis. Conclusions As the duration of second stage of labour increased each hour, the risk of obstetric anal sphincter injuries, episiotomies and PPH increases significantly. Women were over 2 times more likely to have a forceps or caesarean birth. The association between adverse perinatal outcomes and the duration of second stage of labour was less convincing in this study.

Second Stage of Labor in Obese Patients: Calling for a New Definition

“…A randomized control trial conducted by Gimovsky et al demonstrated that an extra hour of pushing reduced the incidence of cesarean delivery from 43.2 to 19.5% without increasing maternal and neonatal morbidity [19]. There have been several studies including a large multicenter randomized control trial, cohort studies, and systematic reviews that have also shown no increase in perinatal outcomes with a prolonged second stage of labor [20][21][22]. Therefore, it may be reasonable to extend the second stage pushing time for patients without fetal heart rate abnormalities, especially for obese patients [4].…”

Prolonged passive second stage of labour in nulliparous women: A multi perspective study

“…There is a large number of studies describing birth outcomes in relation to the second stage, but most of them lack a division of the passive and active second stage. A prolonged second stage has been associated with adverse maternal outcomes: postpartum haemorrhage (PPH), infection, obstetric anal sphincter injury (OASI) (71), IB, CS, and episiotomies (72)(73)(74)(75)(76)(77)(78)(79) in nulli-and parous women. A new policy in labour management in the United States in 2014 aimed to reduce the CS rate for nulliparous women by adding an additional hour before diagnosing a prolonged second stage.…”

“…The relationship between the duration of the second stage and adverse neonatal outcomes has been investigated with conflicting results. Several studies found no association between a prolonged second stage and neonatal adverse outcomes (76,79,(92)(93)(94)(95) others showing negative effects of birth asphyxia, low 5-minute Apgar score and perinatal mortality (72-74, 77, 78, 96-99). When dividing the second stage into the passive and active stages, prolongation of the passive second stage showed no increased risk of umbilical artery acidosis, but increased rates of admissions to the Neonatal intensive care unit (NICU).…”