Obstetrician call schedule and obstetric outcomes among women eligible for a trial of labor after cesarean

Abstract

Background: Reducing cesarean deliveries is a major public health goal. The low rate of vaginal birth after cesarean has been attributed largely to a decrease in the likelihood of choosing a trial of labor after cesarean, despite evidence suggesting a majority of women with 1 prior low transverse cesarean are trial of labor after cesarean candidates. Although a number of reasons for this decrease have been explored, it remains unclear how systems issues such as physician call schedules influence delivery approach and mode in this context.

Objective: The objective of the study was to investigate the relationship between obstetricians' call schedule and obstetric outcomes among women eligible for a trial of labor after cesarean.

Study design: This is a retrospective cohort study of the likelihood of attempting a trial of labor after cesarean and achieving vaginal birth after cesarean among women with 1 prior low transverse cesarean delivery and a term, cephalic singleton gestation based on the delivering provider's call schedule. Attending obstetrician call schedules were classified as traditional or night float call. Night float call was defined as a schedule in which the provider had clinical responsibilities only for a day or night shift, without other clinical responsibilities before or after the period of responsibility for laboring patients. Call schedules are determined by individual provider groups. Bivariable analyses and random-effects logistic regression were used to examine the relationship between obstetricians' call schedule and the frequency of trial of labor after cesarean. Secondary outcomes including frequency of vaginal birth after cesarean and maternal and neonatal outcomes also were assessed.

Results: Of 1502 eligible patients, 556 (37%) were delivered by physicians in a night float call system. A total of 22.6% underwent a trial of labor after cesarean and 12.8% achieved vaginal birth after cesarean; the vaginal birth after cesarean rate for women attempting a trial of labor after cesarean was 56.5%. Women were more likely to undergo a trial of labor after cesarean (33.1% vs 16.5%, P < .001) and achieve vaginal birth after cesarean (18.7% vs 9.3%, P < .001) when cared for by physicians with a night float call schedule. Regression analyses demonstrated physicians with a night float call schedule remained significantly more likely to have patients undergo trial of labor after cesarean (adjusted odds ratio, 2.64, 95% confidence interval, 1.65-4.25) and experience vaginal birth after cesarean (adjusted odds ratio, 2.17, 95% confidence interval, 1.36-3.45) after adjusting for potential confounders. However, the likelihood of achieving vaginal birth after cesarean if a trial of labor after cesarean was attempted was not different based on provider call type (adjusted odds ratio, 0.96, 95% confidence interval, 0.57-1.62). Although women delivered by providers with a night float schedule were more likely to experience uterine rupture (1.8% vs 0.6%, P = .03), chorioamnionitis (4.3% vs 1.7%, P = .002), postpartum hemorrhage (7.6% vs 4.8%, P = .03), and neonates admitted to the neonatal intensive care unit (6.8% vs 3.9%, P = .01), these associations did not persist when the population was limited to women attempting trial of labor after cesarean.

Conclusion: Although physicians working on a night float call system were significantly more likely to have patients with a prior cesarean undergo trial of labor after cesarean and achieve vaginal birth after cesarean, their patients also were more likely to experience maternal and neonatal morbidity. However, these differences did not persist when limiting analyses to women attempting a trial of labor after cesarean. Using a night float call schedule may be an effective measure to promote a trial of labor after cesarean and vaginal birth after cesarean.

Keywords: call schedule; night float; physician schedule; trial of labor after cesarean; vaginal birth after cesarean.