Association Between Genital Hiatus Size 8 Weeks Postpartum and Pelvic Organ Prolapse 1 Year After the First Vaginal Delivery

Importance Evidence suggests that genital hiatus (GH) enlargement precedes pelvic organ prolapse development remote from delivery. However, the association of postpartum GH enlargement and prolapse is unknown. Objective The aim of this study was to determine the association between enlarged GH at 8 weeks postpartum and prolapse 1 year after first vaginal delivery. Study Design This is a secondary analysis of the Motherhood and Pelvic Health study, a prospective cohort of women after their first vaginal delivery. Enlarged GH was defined as >= 4 cm. Prolapse was defined as Pelvic Organ Prolapse Quantification points Ba, Bp, or C at or beyond the hymen. Kaplan-Meier analysis and proportional hazards modeling were used to analyze the association between enlarged GH at 8 weeks postpartum and prolapse at 1 year postpartum. Diagnostic test characteristics of enlarged GH were calculated. Results Five hundred eighty women were included. At 1 year postpartum, the prevalence of prolapse was 3 times higher in women with, versus without, an enlarged GH at 8 weeks postpartum (16% vs 5%, P < 0.001). This was confirmed in a Cox proportional hazards model while adjusting for age, body mass index, and early postpartum prolapse (adjusted hazard ratio, 3.3; 95% confidence interval, 1.85-6.06; P < 0.001). The diagnostic properties of postpartum GH to predict prolapse at 1 year are as follows: sensitivity, 0.63; specificity, 0.67; positive predictive value, 0.17; and negative predictive value, 0.95. Conclusions Women with an enlarged GH at 8 weeks postpartum have a 3.3-fold increased risk of prolapse at 1 year. As a screening tool, GH <4 cm at 8 weeks postpartum has high negative predictive value.