Over 85% of women having a vaginal birth suffer some perineal trauma. Spontaneous tears requiring suturing are estimated to occur in at least a third of women in the UK and US, with anal sphincter tears in 0.5% to 7% of women. Perineal trauma can lead to long-term physical and psychological problems.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of intrapartum surgical and non-surgical interventions on rates of perineal trauma? What are the effects of different methods and materials for primary repair of first- and second-degree tears and episiotomies? What are the effects of different methods and materials for primary repair of obstetric anal sphincter injuries (third- and fourth-degree tears)? We searched: Medline, Embase, The Cochrane Library, and other important databases up to March 2010 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
We found 38 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
In this systematic review we present information relating to the effectiveness and safety of the following interventions: active pushing, spontaneous pushing, and sustained breath-holding (Valsalva) method of pushing; continuous support during labour; conventional suturing; different methods and materials for primary repair of obstetric anal sphincter injuries; episiotomies (midline and mediolateral incisions); epidural analgesia; forceps; methods of delivery ("hands-on" method, "hands poised"); water births; non-suturing of muscle and skin (or perineal skin alone); passive descent in the second stage of labour; positions (supine or lithotomy positions, upright position during delivery); restrictive or routine use of episiotomy; sutures (absorbable synthetic sutures, catgut sutures, continuous sutures, interrupted sutures); and vacuum extraction.
Over 85% of women having a vaginal birth suffer some perineal trauma.
Spontaneous tears requiring suturing are estimated to occur in at least one third of women in the UK and US, with anal sphincter tears in 0.5% to 7% of women.Risk factors include first vaginal delivery, large or malpositioned baby, older or white mother, abnormal collagen synthesis, poor nutritional state, and forceps delivery.
Perineal trauma can lead to long-term physical and psychological problems.
Up to 10% of women continue to have long-term perineal pain; up to 25% will have dyspareunia or urinary problems, and up to 10% will report faecal incontinence.
Restricting routine use of episiotomy reduces the risk of posterior perineal trauma.
Using episiotomies only when there are clear maternal or fetal indications increases the likelihood of maintaining an intact perineum, and does not increase the risk of third-degree tears.
We don't know whether pain or wound dehiscence are less likely to occur with midline episiotomy compared with mediolateral incision.
Midline incisions may be more likely to result in severe tears, although we can't be sure about this.
Instrumental delivery increases the risk of perineal trauma.
The risk of instrumental delivery is increased after epidural analgesia. Vacuum extraction reduces the rate of severe perineal trauma compared with forceps delivery, but increases the risk of cephalhaematoma and retinal haemorrhage in the newborn.
Continuous support during labour reduces the rate of assisted vaginal births, and thus the rate of perineal trauma.
The "hands-poised" delivery method is associated with lower rates of episiotomy, but increased rates of short-term pain and manual removal of the placenta. Likewise, an upright position during delivery is associated with lower rates of episiotomy, but no significant difference in overall rates of perineal trauma.
Non-suturing of first- and second-degree tears (perineal skin and muscles) may be associated with reduced wound healing up to 3 months after birth. However, leaving the perineal skin alone unsutured (vagina and perineal muscles sutured) reduces dyspareunia and may reduce pain at up to 3 months.
Absorbable synthetic sutures for repair of first- and second-degree tears and episiotomies are less likely to result in long-term pain than catgut sutures. Rapidly absorbed synthetic sutures reduce the need for suture removal. Continuous sutures reduce short-term pain.
Early primary overlap repair for third- and fourth-degree anal sphincter tears seems to be associated with lower risks for faecal urgency and anal incontinence symptoms than end-to-end approximation.
We don't know whether immersion in water during the first or second stage of labour has any effect on rates of perineal trauma or whether passive descent is better than active pushing.
It is unclear whether the sustained breath holding (Valsalva) method is more effective at reducing rates of perineal trauma compared with exhalatory or spontaneous pushing.