Transcriptomic evidence of remodeling in postpartum levator ani muscle associated with maternal age and recovery time after first vaginal delivery

BACKGROUND: Older maternal age at first vaginal delivery, defined in some studies as ≥30 years old, confers a substantial increased risk of pelvic organ prolapse. Age-related impairment of postpartum recovery of levator ani muscles may help explain this association; yet, little is known about the biomolecular changes that occur in the levator ani after vaginal delivery, or with aging. OBJECTIVE: To evaluate the transcriptional signature of the levator ani immediately after vaginal delivery and 6 to 8 weeks postpartum among young primiparas (18-25 years) and older primiparas (≥35 years). STUDY DESIGN: This study is a prospective study in which nulliparous women were recruited in the third trimester of pregnancy. Levator ani muscle biopsies were obtained immediately after vaginal delivery and at 6 to 8 weeks postpartum. Clinical measures of pelvic floor support and levator ani muscle function were obtained at the 6 to 8-week postpartum visit. Biopsies were analyzed using RNA sequencing methods and differentially expressed genes were compared with those reported in prior studies of pelvic organ prolapse patients. We used a moderated t test (false discovery rate