Levator ani function before and after childbirth.

OBJECTIVE To evaluate pelvic floor muscle strength before and after vaginal birth. DESIGN Prospective repeated measures study. SETTING Main district hospital. POPULATION Fifty-five women: 25 primiparae and 20 multiparae following vaginal birth, and 10 women following elective caesarean delivery as a control group. METHODS Pelvic muscle strength was evaluated by palpation, perineometry and perineal ultrasound before childbirth in the 36th to 42nd week of pregnancy, three to eight days postpartum and six to ten weeks postpartum. MAIN OUTCOME MEASURES Pelvic floor muscle strength on palpation, intravaginal squeeze pressure and vesical neck elevation during squeeze. RESULTS Pelvic floor muscle strength is significantly reduced three to eight days postpartum in women following vaginal birth but not in women after caesarean delivery. Six to ten weeks later palpation and vesical neck elevation on perineal ultrasound do not show any significant differences to antepartum values, while intravaginal pressure on perineometry remains significantly lower in primiparae, but not in multiparae. CONCLUSIONS Pelvic floor muscle strength is impaired shortly after vaginal birth, but for most women returns within two months.