Impact of labour and delivery on pelvic floor: perineometry and clinical evaluation. Any protecting factor?

Objective: Instrumental delivery, anal sphincter laceration and long second stage are considered the main obstetric risk factors contributing to cause injuries to the levator ani muscle (LAM). The primary aim of our study was to compare pelvic floor muscles strength (PFMS) out of labour, during labour and after delivery through clinical evaluation by pubococcigeal test and instrumental evaluation by perineometry. The secondary aim was to investigate some variables related to pregnancy and delivery as potential predictors of pelvic floor dysfunctions. Materials and Methods: This longitudinal study included nulliparous pregnant women who were enrolled between October and December 2018. Women underwent pubococcigeal test and perineometry to assess PFMS before labour (T0 ), during labour (T1 ) and at puerperium (T2 ). Then we analysed which obstetric parameters had influenced our results. Results: Forty-nine women completed the study. Pubococcigeal test and perineometry at maximal LAM contraction showed a decrease in strength between T0 and T2 . Basal perineometry showed no statistical difference throughout the time. Urinary symptoms had not impact on our results while episiotomy, perineal lacerations, duration of labour and participation to a childbirth class were influent on LAM at rest or at contraction. Conclusion: Labour and delivery alter the contraction force of the PFMs, but not the resting muscle tone. Episiotomy, perineal lacerations and duration of labour have negative impact on PFMs; participation to the childbirth, instead, could be a protecting factor for pelvic floor muscle strength.