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.