Childbirth and the pelvic floor: “the gynaecological consequences”

This review addresses the effects of childbirth on the pelvic floor, urinary continence mechanisms and the perineum. Genitourinary prolapse affects 15% of women and stress incontinence 20–30%. The major risk factors are age and childbirth, with severity increasing with parity. There are three mechanisms of support for the pelvic organs and bladder neck. These are (i) the muscular component: levator ani and urethral sphincter with their intact nerve supply, (ii) the endopelvic fascial connections with the levator ani, and (iii) the posterior angulation of the vagina. Childbirth causes direct myogenic damage, dennervation and defects in the endopelvic fascia along with widening of the urogenital hiatus. Elective caesarean section without labour has in the past thought to be protective. More recent data suggests this effect to be less pronounced and antenatal stress incontinence appears the most important predictive factor for the development of postnatal stress incontinence. The targeting of pelvic floor exercises under direct supervision from a physiotherapist have shown a reduction in the development of short and long term stress urinary incontinence.

Perineal trauma can effect up to 85% of women after vaginal delivery. The consequences of this include perineal pain and dyspareunia lasting up to 12 months postnatally. Nulliparity and the use of forceps have been identified as the major risk factors along with occipito-posterior position, macrosomia and episiotomy as secondary factors. The role of selective mediolateral episiotomy and methods of perineal repair are discussed.