Preconceptional counseling of women with previous third and fourth degree perineal tears

More than 85% of women in the United Kingdom (UK) sustain some form of perineal trauma during childbirth1. In the majority of instances, only the perineal skin, vaginal epithelium and superficial muscles are involved, and such tears are only rarely associated with serious sequelae. Tears involving the anal sphincter, however, can have long-term impact on a woman’s quality of life. Sultan2 originally proposed the classification of obstetric anal sphincter injuries (OASIS) shown in Figure 1; this classification was later adopted by the Royal College of Obstetricians and Gynaecologists3 and subsequently internationally accepted. A schematic representation of the anal sphincter is depicted in Figure 2. The prevalence of third and fourth degree tears appears to be dependent upon the type of episiotomy practised and thus varies considerably. In centers where mediolateral episiotomy is practised, the rate of OASIS is 1.7% (2.9% in primiparas), compared to 12% (19% in primiparas) in units that perform midline episiotomy4. This chapter describes the salient points that should be covered at the preconceptional consultation of a woman who has sustained a third or fourth degree OASIS. What this chapter does not cover specifically are the risk factors of anal sphincter injuries, evidence on how to prevent such injuries at first vaginal delivery, methods of repair of severe perineal tears and management of anal incontinence (whether surgical or medical). 20 Preconceptional counseling of women with previous third and fourth degree perineal tears