A new study published in JAMA suggests that vaginal childbirth substantially increases the probability a woman will develop a pelvic floor disorder, such as incontinence, later on in life.
Researchers at Johns Hopkins University (JHU; Baltimore, MD, USA), and the Greater Baltimore Medical Centre (GBMC; MD, USA) conducted a study that recruited 1,528 women within five to 10 years of their first birth, who were followed up annually for up to nine years. Recruitment was based on mode of delivery; 778 delivered all of their children via caesarean birth, 565 had at least one spontaneous vaginal delivery, and 185 had at least one delivery involving forceps or vacuum-assistance.
Information was collected at the time of enrolment, including date and age at first birth, body mass index (BMI), birth delivery mode, genital hiatus size, and whether they had developed any prior pelvic floor disorder; delivery groups were then matched for age and years since first delivery. Main outcomes and measures included presence of stress urinary incontinence (SUI), overactive bladder (OAB), and anal incontinence (AI). Some women already had developed pelvic floor disorders at the time of study enrolment, while others developed the conditions over the course of the study.
The results showed that caesarean delivery substantially reduced the risk of pelvic floor disorders, most notably pelvic organ prolapse, while operative delivery increased the risk. For pelvic organ prolapse, the magnitude of these differences grew over time. By 15 years after a first delivery, prolapse of the uterus or vaginal wall beyond the vaginal opening was seen in 9% of women who had delivered by caesarean, 30% in those who had at least one vaginal delivery, and 45% in those who had at least one operative delivery.
The researchers also found that a large percentage of new cases of urinary and bowel incontinence developed in the first five years after delivery, while pelvic organ prolapse tended to develop many more years after childbirth. A third discovery was that the genital hiatus size is significantly associated with all pelvic floor disorders, but most significantly with pelvic organ prolapse. According to the researchers, this suggests that the genital hiatus size is a marker that can identify women at high risk of developing pelvic floor disorders with aging.
“We knew that these disorders are more common after childbirth, but now after following these women for 10 years, we have a good sense of how delivery mode impacts a woman’s risk of developing a pelvic floor disorder,” said senior author Prof Victoria Handa, MD, MHS, of JHU.
“Ultimately this research will help us identify which women should be targeted for prevention strategies, and will hopefully improve our ability to deliver the right type of care to the right person.”
REFERENCE: Blomquist et al: Association of Delivery Mode With Pelvic Floor Disorders After Childbirth; https://jamanetwork.com/journals/jama/article-abstract/2718794