Introduction: The natural history of pelvic organ prolapse (POP) is poorly understood. We investigated the prevalence and risk factors of postnatal POP in premenopausal primiparous women and the associated effect of mode of delivery.
Methods: We conducted a prospective cohort study in a tertiary teaching hospital attending 9,000 deliveries annually. Collagen-diseases history and clinical assessment was performed in 202 primiparae at ≥ 1 year postnatally. Assessment included Pelvic Organ Prolapse Quantification (POP-Q) system, Beighton mobility score, 2/3D-transperineal ultrasound (US) and quantification of collagen type III levels. Association with POP was assessed using various statistical tests, including logistic regression, where results with p < 0.1 in univariate analysis were included in multivariate analysis.
Results: POP had a high prevalence: uterine prolapse 89 %, cystocele 90 %, rectocele 70 % and up to 65 % having grade two on POP-Q staging. The majority had multicompartment involvement, and 80 % were asymptomatic. POP was significantly associated with joint hypermobility, vertebral hernia, varicose veins, asthma and high collagen type III levels (p < 0.05). In multivariate logistic regression, only levator ani muscle (LAM) avulsion was significant in selected cases (p < 0.05). Caesarean section (CS) was significantly protective against cystocele and rectocele but not for uterine prolapse.
Conclusions: Mild to moderate POP has a very high prevalence in premenopausal primiparous women. There is a significant association between POP, collagen levels, history of collagen disease and childbirth-related pelvic floor trauma. These findings support a congenital contribution to POP etiology, especially for uterine prolapse; however, pelvic trauma seems to play paramount role. CS is significantly protective against some types of prolapse only.