Longitudinal pelvic floor biometry: which factors affect it?

<bold>Objectives: </bold>To evaluate pelvic floor biometry of women 3-5 years after their first delivery. The effect of a subsequent delivery and the mode of delivery on pelvic floor biometry were also studied.<bold>Methods: </bold>Three-hundred and twenty-eight women who had been examined by translabial ultrasound during their first singleton pregnancy and at 8 weeks and 1 year postpartum, were invited for a follow-up 3-5 years later. The positions of the bladder neck, cervix, anorectal junction and hiatal area (HA) were evaluated using translabial ultrasound. The effects of parity, mode of delivery and levator ani muscle avulsion were studied.<bold>Results: </bold>A total of 240 women completed the study. Of these, 179 had one or more vaginal deliveries (VD) (VD-only group), 52 had one or more Cesarean sections (CS) (CS-only group) and nine had both VD and CS at follow-up. The mean interval between the first delivery and follow-up was 3.8 years. A significantly lower bladder neck and anorectal junction on Valsalva, a lower cervix at rest, on Valsalva and pelvic floor muscle contraction, and a greater HA were observed in the VD-only group at follow-up, compared with findings at 1 year of follow-up or in the first pregnancy. The findings were similar in the CS-only group, except without a lower anorectal junction on Valsalva. Compared with the primiparous VD-only group, a greater HA at rest was observed in the multiparous VD-only group (P = 0.027). The VD-only group had a greater HA than the CS-only group.<bold>Conclusions: </bold>At 3-5 years after first delivery, a lower bladder neck, cervix and anorectal junction, and a greater HA were observed compared with findings in the first trimester and at 1 year of follow-up, regardless of parity or mode of delivery. Women with two or more VDs had a greater HA compared with those who had only one VD, and women with at least one VD had a greater HA compared with those who delivered by CS only. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]