Vaginal delivery raises risk of pelvic organ prolapse

Women who give birth vaginally are at increased risk of developing pelvic organ prolapse during the year after delivery, according to a study of Chinese women by researchers at Yale School of Medicine and Wenzhou Third People's Hospital.

Published online today in the British Journal of Obstetrics and Gynaecology, the results show that factors unique to labor and delivery made the pelvic floor relax and not recover its former support during the year after birth. These factors were not present in women who delivered via cesarean section (c-section).

''The choice between vaginal birth and c-section is a complex one, and our results are not meant to promote one over the other,'' said Dr. Marsha K. Guess, assistant professor in the Department of Obstetrics, Gynecology & Reproductive Sciences at Yale School of Medicine. ''Our data will be useful to women and their obstetric providers as they weigh childbirth options.''

Pelvic organ prolapse is a common condition among women who have given birth vaginally. Hormonal changes, increased pressure, and the baby's passage through the birth canal can damage connective tissue, muscles, nerves, and blood vessels. The vagina and the surrounding organs relax, lose their support, and fall from their normal positions, leading to a host of complications such as urinary incontinence and bowel control.

It is thought that some women are genetically predisposed to having an abnormal repair process after delivery, which may also contribute to pelvic organ prolapse.

In this prospective observational study, Guess, corresponding author Yi Chen, and colleagues, compared changes in pelvic organ prolapse during late pregnancy with changes at three different points in time within one year after delivery.

Between April and May 2009, they evaluated 110 women at the obstetrics clinic in Wenzhou Third People's Hospital in Wenzhou, Zhejiang, China. These women were in their 36th-38th week of pregnancy and were planning to undergo an elective c-section or vaginal delivery.

They found that many women develop moderate prolapse in late pregnancy; however, women who underwent vaginal delivery or c-section after laboring were less likely to recover from pelvic organ prolapse at six weeks, six months, and one year postpartum, compared to those who delivered after an elective c-section with no labor.

''Our study is among the few that provide information about short- and long-term effects of labor and route of delivery on pelvic floor support to determine if and when recovery of pelvic floor support structures occurs over long durations of time,'' said Guess. ''More research should be done to better identify women at greatest risk for, or predisposed to developing, long-term pelvic floor consequences.''

The study was supported by the ministry of health of Zhejiang province (Granted No.2009B151).

Other authors on the study include Fang Yong Li, Xiaohua Lin, Jingjing Chen, Cong Chen.