Surgery for urinary incontinence and prolapse linked to vaginal parity: Study

Sweden: In females, pelvic floor disorders (PFD) like pelvic organ prolapse (POP) and stress urinary incontinence (SUI) are largely associated with vaginal delivery (VD), according to epidemiologic and imaging studies. The research is published in the American Journal of Obstetrics and Gynecology.

The controversy exists on whether Cesarean deliveries (CD) can reduce the risk of PFDs or not. Two studies have concluded the effect of CD protection on PFDs. No studies have compared the effect of multiple pregnancies, one or more vaginal births, and factors unrelated to childbirth among nulliparous women on the risk of reconstructive urogenital surgery. To add valuable and crucial data to this unresolved issue regarding surgery, a study was conducted by Larsudd-Kåverud et al. and the team at Gothenburg Continence Research Centre, Institute of Clinical Sciences at Sahlgrenska Academy at Gothenburg University, Sweden.

The research data was used from three nationwide registers, namely, the Swedish National Quality Register of Gynecological Surgery, the Swedish Medical Birth Register (to determine the rate of VD, CD, and parity), and the Total Population Register( for women born in 1960, n = 2,309,765)

Women aged ≥ 45 years with a history of urinary incontinence or prolapse surgery between 2010 to 2017 were included, n=59,415. The surgical cohort was divided into nulliparous women, women with one or more cesarean deliveries only, women with one or more vaginal deliveries, and the number of births. With 95% confidence intervals, absolute and relative risks were presented per 1000 women. Fisher exact test was used to determine pairwise differences and the Mann-Whitney U test for dichotomous and continuous variables.

The key points from the study include:

• 39,617 women underwent prolapse surgery, and 20,488 underwent incontinence surgery.

• 97.8 % had ≥ 1 vaginal delivery, 0.4 % had ≥ 1 cesarean delivery, and 1.9 % were nullipara among the women with prolapse surgery. The corresponding percentage in the incontinence surgeries was 93.1 %, 2.6 %, and 4.3 % respectively.

• Women with vaginal deliveries were overrepresented in the prolapse surgery with a relative risk of 1.23 and P value < 0.001, and the relative risk was 1.17 with P < 0.001 in incontinence surgical groups.

• Nulliparous women and Cesarean-delivered women were underrepresented in the prolapse surgery ( relative risk of 0.14 and 0.55 with P value <0.001) and incontinence surgery groups (relative risk of 0.31 and 0.40)

• After cesarean delivery, the absolute risk (AR) for prolapse surgery was lowest at 0.09 per 1000 women, which differed by a factor of 23 (2.11 per woman) from vaginal births.

• There was an increase in AR for prolapse and incontinence surgery consistent with parity after vaginal births. The increase was six-fold in pelvic organ prolapse surgery after the first vaginal birth and three-fold in SUI surgery.

• The AR was lowest in the second vaginal birth for pelvic organ prolapse surgery (~1/3 of the first vaginal birth) and SUI surgery ((~1/10 of the first vaginal birth).

• Cesarean deliveries do not show this trend and are on par with nulliparous women.

The researchers said that " VD is the sole dominant risk factor for subsequent urogenital surgery with first vaginal birth being largest and second being smallest additive AR while CD seems to maintain the nulliparous state of pelvic floor support in the long term." The study is a landmark in highlighting the reproductive burden and the quality of women's lives in relation to  PFD and vaginal parity.

Reference:

Larsudd-Kåverud J, Gyhagen J, Åkervall S, Molin M, Milsom I, Wagg A, Gyhagen M. The influence of pregnancy, parity, and mode of delivery on urinary incontinence and prolapse surgery-a national register study. Am J Obstet Gynecol. 2022 Aug 3:S0002-9378(22)00591-9. doi: 10.1016/j.ajog.2022.07.035. Epub ahead of print. PMID: 35932880.