Postpartum recovery of levator hiatus and bladder neck mobility in relation to pregnancy.

OBJECTIVE: To study postpartum changes in pelvic floor morphology in a cohort of primiparous women.
METHODS: Transperineal ultrasound measurements taken at five examination points, both prepartum and postpartum, provided data for comparison. Three hundred nulliparous pregnant women were examined at 21 weeks of gestation and 274 (91%) at 37 weeks of gestation. At 6 weeks postpartum, 285 (95%) women were examined, 198 (66%) at 6 months, and 178 (59%) at 12 months using transperineal ultrasonography at rest, during contraction, and during Valsalva maneuver. The levator hiatus area, bladder neck mobility, and rest-to-Valsalva hiatal area difference were assessed.
RESULTS: Approximately 85% had vaginal and 15% had cesarean deliveries. Demographic characteristics of the patients lost to follow-up were similar to the patients not lost to follow-up. In the vaginal group, a significant decrease in all measurements was seen during the first 6 months postpartum, being most pronounced for the levator hiatus area during Valsalva maneuver (-3.5 cm; P<.001). In the cesarean delivery group, no significant changes between examination points were found postpartum. Only the vaginal delivery group showed significant increases in all measurements when comparing the status at 12 months postpartum with 21 weeks of gestation, most pronounced for levator hiatus area during Valsalva maneuver (3 cm; P<.001). However, comparing the two delivery groups at 12 months postpartum, the only significant difference found was levator hiatus area during contraction.
CONCLUSION: The levator ani muscle has the ability to recover after pregnancy and delivery, although not all women recover to pregnancy level. Most of the recovery occurs during the first 6 months postpartum. Significant pregnancy-induced changes are not shown to persist 1 year postpartum. LEVEL OF EVIDENCE: : II.