Reviews in Gynaecological Practice 5 (2005) 15–22 www.elsevier.com/locate/rigp Childbirth and the pelvic floor: ‘‘the gynaecological consequences’’ Christian Phillips a,1, Ash Monga b,* a The North Hampshire Hospital, Aldermaston Road, Basingstoke, Hampshire RG24 9NA, UK b Princess Anne Hospital, Coxford Road, Southampton SO16 5YA, UK Received 28 May 2004; accepted 15 September 2004 Abstract 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. # 2004 Elsevier B.V. All rights reserved. Keywords: Childbirth; Pelvic floor; Stress urinary incontinence; Continence mechanisms; Perineal trauma; Prevention of stress incontinence; Episiotomy 1. Introduction tinence, and perineal trauma, its subsequent repair, dyspareunia and perineal pain. The strength of the muscles of the pelvic floor and other supporting structures of the pelvic organs are affected by various events that occur during a woman’s lifetime. Pregnancy and childbirth have a pronounced influence on 2. Epidemiology maternal anatomy and physiology. After this, menopause and aging have a secondary effect on the pelvic floor. This Genitourinary prolapse is a common and distressing review concentrates on the long term gynaecological condition affecting up to 15% of the female population and consequences of pregnancy and childbirth with respect to is responsible for around 20% of women on waiting lists pelvic floor weakness, its incidence, its pathophysiology and for major gynaecological surgery [1]. It is defined as the ways in which it may be prevented. protrusion of a pelvic organ or structure beyond its normal The longer-term gynaecological sequelae of pelvic floor confines within the pelvis. Epidemiological studies have weakness are pelvic organ prolapse, stress urinary incon- shown a woman has an 11.1% lifetime risk of undergoing a single operation for prolapse or incontinence by the age of 80 [2]. The incidence of women admitted to hospital with * Corresponding author. Tel.: +44 2380 798504; fax: +44 2380 794801. E-mail addresses: [email protected] (C. Phillips), prolapse is 2.04 per 1000 person-years of risk [3].The [email protected] (A. Monga). main risk factors associated with prolapse are parity and 1 Tel.: +44 171 594 7575; fax: +44 171 594 7580. increasing age, whilst smoking and obesity are secondary 1471-7697/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.rigp.2004.09.002 16 C. Phillips, A. Monga / Reviews in Gynaecological Practice 5 (2005) 15–22 factors. Recurrence rates are high, rising with time after 3.1. Muscular supports hysterectomy [3]. Cumulative risk of recurrence rose from 1% after 3 years to 5% after 15 years. Women have a 5.5 The muscular support of the pelvic viscera is mainly times higher risk of recurrence if their hysterectomy is for provided by the levator ani muscles: iliococcygeus and prolapse rather than other pathology. The Womens’ Health pubococcygeus. The iliococcygeus muscles form a sheet- Initiative studied approximately 27,000 women. This study like structure extending from the arcus tendineus ante- quotes prevalence rates for each type of prolapse; uterine riorly, travelling behind the rectum to meet a midline raphe prolapse; 14%, cystocele; 34% and rectocele; 18% of fused posteriorly to the coccyx. The two muscles act as a women [4]. Prolapse is rare in Afro-Carribean women plate lying over the urogenital hiatus, upon which the compared with a Caucasian population, which may be due pelvic viscera lie. When the levator ani muscles relax the to differences in their connective tissue [5].Studiesof urogenital hiatus widens and the suspensory ligaments, sisters have shown that genetic predisposition may be more made of connective tissue are left holding the uterus and importantthanotherriskfactorssuchasparityinthe vagina in place. This has been confirmed using three- development of prolapse [6]. dimensional ultrasound of the levator ani hiatus. Measure- Urinary incontinence is defined by the International ments show that the hiatus is larger in women with Continence society as the involuntary loss of urine that is a prolapse than in those without [18]. Control of levator tone social or hygienic problem. In population estimates the at rest and at stress is maintained by an intact nerve supply. incidence of urinary incontinence ranges from 20 to 30%, The levator ani muscles are innervated by the anterior with 7–12% of women perceiving it as a problem [7].Itis sacral nerve roots of S2–4. The pubococcygeus muscle estimated that 1–4% of the population suffer restriction to forms a sling-like structure around the urogenital hiatus their daily activities because of their incontinence. Risk andsoisinvolvedinsphinctericmechanismsofthe factors for the development of urinary incontinence are age urethra. The pubococcygeus muscle, along with the and childbirth. The prevalence of urinary symptoms peaks external anal sphincter is innervated by branches of the at 45–55 years and again at 70 years [8]. Severe forms of pudendal nerve (S2–4). incontinence are more common with older age, with a 30% greater prevalence for each 5-year increase in age [9]. 3.2. Connective tissue supports Stress incontinence affects 16% of 17–25-year olds and is more common in parous women compared with nullipar- Integrity of the endopelvic fascia is also important in ous women [10]. Workers have found that stress the support of the uterus, bladder and bowel. Anteriorly incontinence in the nulliparous population is associated the pelvic fascia forms the pubourethral ligaments. These with inherent deficiencies in their connective tissue lie either side of the midline to form an aponeurotic plate [11,12]. Urinary symptoms are found antenatally in up supporting the cranial aspect of the proximal urethra. The to 60% of pregnant women [13]. Postnatally, the pubourethral ligaments extend anteriorly becoming con- prevalence of urinary incontinence varies in reports from tinuous with the suspensory ligament of the clitoris. The 6to34%[14–16]. endopelvic fascia then extends as a fibrous band running from the symphysis pubis anteriorly, widening posteriorly to attach to the ischial spine. This structure called the arcus 3. Normal anatomy of pelvic support tendineus fascia pelvis (ATFP) is also known as the ‘‘white line’’, and can easily be seen in the space of Retzius at The uterus and vaginal apex are supported by a muscular colposuspension. The fascia extends continuously from component, which requires an intact nerve supply, and a the symphysis pubis anteriorly, the arcus tendineus fascial component. Damage to any of these can lead to and levator ani muscles laterally to the ischial spines prolapse of the pelvic organs. posteriorly, enveloping the pelvic organs. In areas the Victor Bonney described three mechanisms of support fascia forms condensations called ligaments, e.g. the that exist in the female pelvis: constriction, suspension and uterosacral/cardinal complex. The endopelvic fascia is flap-valve closure [17]. made up mainly of connective tissue and smooth muscle in various proportions according to site and structure [19]. 1. Constriction of the vagina by the levator ani occludes the The cardinal ligaments contain perivascular connective levator hiatus through which prolapse of pelvic structures tissue whereas the uterosacral ligaments are predomi- can occur. nantly smooth muscle and connective tissue [20,21] 2. The angulation of the vagina, which allows it to close (see Fig. 1). Mengert demonstrated in experiments on against the levator plate on increasing the intra- cadavers that the urterosacral ligaments, parametrium and abdominal pressure. paracolpium are most important in the support of the 3. Fascia and ligaments suspend the uterus, bladder uterus and vagina and this has been further shown to and bladder neck, and rectum to the pelvic side- involve three levels of support to the pelvic viscera walls. [22,23]: C. Phillips, A. Monga / Reviews in Gynaecological Practice 5 (2005) 15–22 17 Fig. 1. Section through uterosacral ligament