Hypothesis / aims of study
It has been said that the first term pregnancy in a woman causes damage to the pelvic floor. (1) Hormonal and mechanical effects of a gravid uterus on the bladder increase the risk of urinary incontinence irrespective of mode of delivery (i.e. either vaginal or caesarean section). Vaginal delivery, particularly if prolonged in the second stage, operative, or of a large for gestational age baby increases a woman's risk of developing pelvic floor dysfunction, urinary incontinence, and prolapse. However is there variation in the risk of requiring surgery for vaginal prolapse secondary to incontinence or pelvic floor dysfunction depending on parity? This study looks at trends across different parities in a cohort of patients receiving corrective prolapse surgery.
Study design, materials and methods
614 procedures were performed between 2008 and 2019 at a university teaching hospital for repair of prolapse secondary to either incontinence or pelvic floor dysfunction. Anonymised patient details for patients who underwent surgery were collected contemporaneously into the national BSUG database and extracted retrospectively for analysis in an Excel spread sheet. All patients with missing data concerning parity were excluded (23).
Over the 10 year period 591 patients had surgery for prolapse either involving the uterus, vault, anterior, or posterior vaginal wall. The average age of the patients was 70 years, ranging from 34 to 95. The majority of patients had two term pregnancies (45%) and parity ranged from 0 to 8. Procedures undertaken for uterine prolapse included vaginal hysterectomy (259) or hysteropexy (9) of which majority of patients had 2 term deliveries. Procedures for anterior wall prolapse repair totalled 291 including anterior colporrhaphy and transobturator insertion of mesh (TOAR Avaulta). Procedures for posterior wall prolapse included posterior colporrhaphy and mesh posterior repair (MPR) totalling 101 and treatment for vault prolapse involved sacrospinous fixation, sacrocolpocervicopexy, or colpoclesis (232). Bar hysteropexy, majority of the patients for all prolapse compartments had 2 term deliveries between averaging 42-48% of the number of patients. There was a higher rate of patients with 4 or more term deliveries requiring vault prolapse surgery (34 patients, 15%) compared with other compartment prolapses at 13, 22% (uterine); 16, 5.5% (anterior compartment); and 4,4% (posterior compartment).
Interpretation of results
The majority of patients had 2 term pregnancies prior to receiving all forms of surgery for prolapse apart from hysteropexy. This is not surprising given the national average of children per woman is currently 1.9 (2), although for this cohort of women in their 7th decade of life, the average number of children is most likely closer to 2.4. Women requesting hysteropexy had on average 1 child (25%) but no women underwent the procedure that were nulliparous. What’s more as there were a higher proportion of patients with 4 or more term deliveries requiring surgery for vault prolapse, this may be an indication that grand multiparous women are more likely to develop uterine or vault prolapse compared with other compartment prolapse. Notwithstanding, as 8.6% of women who underwent corrective surgery for vault prolapse were nulliparous, there are clearly other risk factors predisposing to vaginal prolapse apart from term delivery. The study was limited as data collected in the BSUG database did not specify whether women had vaginal deliveries or caesarean section nor did we analyze whether the women were having primary or repeat procedures.