Planned mode of birth after previous cesarean section and risk of undergoing pelvic floor surgery: A Scottish population-based record linkage cohort study

Abstract

Background The global rise in cesarean sections has led to increasing numbers of pregnant women with a history of previous cesarean section. Policy in many high-income settings supports offering these women a choice between planned elective repeat cesarean section (ERCS) or planned vaginal birth after previous cesarean (VBAC), in the absence of contraindications to VBAC. Despite the potential for this choice to affect women’s subsequent risk of experiencing pelvic floor disorders, evidence on the associated effects to fully counsel women is lacking. This study investigated the association between planned mode of birth after previous cesarean section and the woman’s subsequent risk of undergoing pelvic floor surgery. Methods and findings A population-based cohort study of 47,414 singleton term births in Scotland between 1983 to 1996 to women with 1 or more previous cesarean sections was conducted using linked Scottish national routine datasets. Cox regression was used to investigate the association between planned as well as actual mode of birth and women’s subsequent risk of having any pelvic floor surgery and specific types of pelvic floor surgery adjusted for sociodemographic, maternal medical, and obstetric-related factors. Over a median of 22.1 years of follow-up, 1,159 (2.44%) of the study population had pelvic floor surgery. The crude incidence rate of any pelvic floor surgery per 1,000 person-years was 1.35, 95% confidence interval (CI) 1.27 to 1.43 in the overall study population, 1.75, 95% CI 1.64 to 1.86 in the planned VBAC group and 0.66, 95% CI 0.57 to 0.75 in the ERCS group. Planned VBAC compared to ERCS was associated with a greater than 2-fold increased risk of the woman undergoing any pelvic floor surgery (adjusted hazard ratio [aHR] 2.38, 95% CI 2.03 to 2.80, p Conclusions This study suggests that among women with previous cesarean section giving birth to a singleton at term, planned VBAC compared to ERCS is associated with an increased risk of the woman subsequently undergoing pelvic floor surgery including surgery for pelvic organ prolapse and urinary incontinence. However, these risks appear to be only apparent in women who actually give birth vaginally as planned, highlighting the role of vaginal birth rather than labor in pelvic floor dysfunction requiring surgery. The findings provide useful additional information to counsel women with previous cesarean section about the risks and benefits associated with their future birth choices. In a Scottish population-based record linkage cohort study, Dr Kathryn E. Fitzpatrick and colleagues, investigate planned mode of birth and the risk of subsequent pelvic floor surgery following previous cesarean section. Author summary Why was this study done? The global rise in cesarean section rates has led to increasing numbers of pregnant women with a history of previous cesarean section. Pregnant women with a history of previous cesarean section may be given a choice between planned elective repeat cesarean section (ERCS) or planned vaginal birth providing they do not have medical reasons why a vaginal birth is not recommended. While clinical guidelines recommend that women should be counseled on the associated risks and benefits to help them make an informed decision about this choice, there is a lack of evidence about the effect of this choice on long-term outcomes including women’s subsequent risk of experiencing pelvic floor disorders including pelvic organ prolapse, urinary incontinence, rectal prolapse, and fecal incontinence. What did the researchers do and find? We conducted a cohort study of 47,414 singleton term births in Scotland to women with 1 or more previous cesarean sections to determine the association between planned as well as actual mode of birth after previous cesarean section and the woman’s subsequent risk of undergoing pelvic floor surgery. We found that planned vaginal birth compared to planned ERCS is associated with a greater than 2-fold increased risk of the woman undergoing any pelvic floor surgery and a 2- to 3-fold increased risk of the woman having surgery for pelvic organ prolapse or urinary incontinence. However, the increased risks seen in the planned vaginal birth group were only apparent in the women who actually gave birth vaginally as planned. Women who needed a non-elective repeat cesarean section during labor have a similar risk of pelvic floor surgery to those who had a planned ERCS. What do these findings mean? Our findings provide additional information to counsel women with previous cesarean section about the risks and benefits associated with their future birth choices.