Cesarean section in a first pregnancy may reduce a woman's risk of having pelvic floor surgery later in life, reported Ramalingam Uma, M.B., and colleagues at the University of Dundee, Scotland.
The researchers said their study was prompted by the increasing attention to pelvic floor morbidity following childbirth, and by indications that cesarean section may be protective against damage to the pelvic floor support structures and impairment of pelvic floor innervation that can occur during vaginal delivery.
The nested case-control study of first-time mothers was drawn from a population of 7,556 women who had given birth in the hospital between 1952 and 1966. Of these women, 5% underwent pelvic floor surgery in later years (BJOG 2005;112:1043–6).
On univariate analysis, cesarean section (odds ratio 0.24) and greater gestational age at birth (OR 0.20) were associated with a reduced risk of pelvic floor surgery, compared with spontaneous vaginal delivery. In the final multivariate model, only cesarean section was associated with reduced odds of future surgery (OR 0.16).
Subgroup analyses comparing the 61 elective and 68 emergency cesarean sections suggested that both were protective against pelvic floor surgery, compared with spontaneous vaginal delivery (OR of 0.19 and 0.29, respectively).
Dr. Uma and colleagues caution that “the absolute risk of pelvic floor surgery in relation to mode of delivery needs to be put in the context of the adverse effect of pregnancy itself. It has been reported that 46% of nullipara have pelvic organ prolapse at 36 weeks antepartum. … Cesarean section may reduce the risk of pelvic floor surgery relating to the mode of delivery but it will not eliminate the risks associated with pregnancy itself.”
In contrast to previous studies, this analysis did not find an association between forceps delivery and increased risk of pelvic floor surgery.