Cervical dilation at time of caesarean delivery in nulliparous women: a population-based cohort study.

OBJECTIVES: Our objective was to describe contemporary practice patterns in the timing of caesarean delivery in relation to cervical dilation, overall and by indication for caesarean. Our secondary objective was to examine how commonly caesarean delivery was performed for labour dystocia at dilations below 4 cm or without the use of oxytocin, overall and between hospitals. DESIGN: Retrospective, population-based cohort study. SETTING: Ontario, Alberta, and British Columbia, Canada, 2008-2012. POPULATION: Nulliparous women in labour who delivered term singletons in cephalic position. METHODS: Histograms were used to examine the distribution of cervical dilation at time of caesarean delivery, overall and by indication for caesarean. Funnel plots were used to illustrate variation in hospital-level rates of caesarean deliveries for labour dystocia that were performed early (<4 cm dilation) or without the use of oxytocin. MAIN OUTCOME MEASURES: Cervical dilation (in centimetres) at time of caesarean delivery. RESULTS: The population-based cohort comprised 392 025 women, of whom 18.8% had a caesarean delivery. Of first-stage caesareans for labour dystocia in women who entered labour spontaneously, 13.6% (95% CI 12.9, 14.2) had dilations <4 cm [hospital-level inter-quartile range (IQR): 6.2% to 20.0%] and 29.5% (95% CI 28.6, 30.4) did not receive oxytocin to treat their dystocia (hospital-level IQR: 22.1-54.6%). CONCLUSIONS: The proportion of caesareans done before 4 cm dilation or without oxytocin varies substantially across hospitals and suggests the need for institutions to review their practices and ensure that management of labour practice guidelines are followed. TWEETABLE ABSTRACT: Many caesareans for labour dystocia are performed early during labour (<4 cm dilation) or without oxytocin.

Maternal and neonatal outcomes after implementation of a hospital policy to limit low-risk planned caesarean deliveries before 39 weeks of gestation: an interrupted time-series analysis.

OBJECTIVE: To evaluate the extent to which implementing a hospital policy to limit planned caesarean deliveries before 39 weeks of gestation improved neonatal health, maternal health, and healthcare costs. DESIGN: Retrospective cohort study. SETTING: British Columbia Women's Hospital, Vancouver, Canada, in the period 2005-2012. POPULATION: Women with a low-risk planned repeat caesarean delivery. METHODS: An interrupted time series design was used to evaluate the policy to limit planned caesarean deliveries before 39 weeks of gestation, introduced on 1 April 2008. MAIN OUTCOME MEASURES: Composite adverse neonatal health outcome (respiratory morbidity, 5-minute Apgar score of <7, neonatal intensive care unit admission, mortality), postpartum haemorrhage, obstetrical wound infection, out-of-hour deliveries, length of stay, and healthcare costs. RESULTS: Between 2005 and 2008, 60% (1204/2021) of low-risk planned caesarean deliveries were performed before 39 weeks of gestation. After the introduction of the policy, the proportion of planned caesareans dropped by 20 percentage points (adjusted risk difference of 20 fewer cases per 100 deliveries; 95% CI -25.8, -14.3) to 41% (1033/2518). The policy had no detectable impact on adverse neonatal outcomes (2.2 excess cases per 100; 95% CI -0.4, 4.8), maternal complications, or healthcare costs, but increased the risk of out-of-hours delivery from 16.2 to 21.1% (adjusted risk difference 6.3 per 100; 95% CI 1.6, 10.9). CONCLUSIONS: We found little evidence that a hospital policy to limit planned caesareans before 39 weeks of gestation reduced adverse neonatal outcomes. Hospital administrators intending to introduce such policies should anticipate, and plan for, modest increases in out-of-hours and emergency-timing.

Using inter-institutional practice variation to understand the risks and benefits of routine labour induction at 41(+0) weeks.

OBJECTIVE: To evaluate the risks and benefits of routine labour induction at 41(+0) weeks' gestation for mother and newborn. DESIGN: Population-based retrospective cohort study of inter-institutional variation in labour induction practices for women at or beyond 41(+0) weeks' gestation. POPULATION: Women in British Columbia, Canada, who remained pregnant ≥41(+0) weeks and delivered at one of the province's 42 hospitals with >50 annual deliveries, 2008-2012 (n = 14,627). METHODS: The proportion of women remaining pregnant a week or more past the expected delivery date who were induced at 41(+0) or 41(+1) weeks' gestation for an indication of 'post-dates' was calculated for each institution. We used instrumental variable analysis (using the institutional rate of labour induction at 41(+0) weeks as the instrument) to estimate the effect of labour induction on maternal and neonatal health outcomes. MAIN OUTCOME MEASURES: Caesarean delivery, instrumental delivery, post-partum haemorrhage, 3rd or 4th degree lacerations, macrosomia, neonatal intensive care unit admission, and 5-minute Apgar score <7. RESULTS: Institutional rates of labour induction at 41(+0) weeks ranged from 14.3 to 46%. Institutions with higher (≥30%) and average (20-29.9%) induction rates did not have significantly different rates of caesarean delivery, instrumental delivery, or other maternal or neonatal outcomes than institutions with lower induction rates (<20%). Instrumental variable analyses also demonstrated no significantly increased (or decreased) risk of caesarean delivery (0.69 excess cases per 100 pregnancies [95% CI -10.1, 11.5]), instrumental delivery (8.9 per 100 [95% CI -2.3, 20.2]), or other maternal or neonatal outcomes in women who were induced (versus not induced). CONCLUSIONS: Within the current range of clinical practice, there was no evidence that differential use of routine induction at 41(+0) weeks affected maternal or neonatal health outcomes.