Perineal Trauma

The perineum is the area between the vagina and the anal region. About 70%-80% of women having their first vaginal delivery will have some stitches somewhere. This could be in the perineal area, in the mucosa inside the vagina and/or in the labia around the vaginal entrance.

First degree tears involve vaginal mucosa and extend out to the labia without involving muscles under the perineal skin. Second degree tears are the most common after vaginal delivery. This involves a tear backwards into the vagina and down the perineum involving the muscles under the perineal skin. It is also possible to have lateral vaginal wall tears as well as a central tear in the vagina and extending down the perineum. Third degree tears are much less common. This occurs when a second-degree tear has extended into the external anal sphincter muscle which is a circular muscle around the anal region. Fourth degree tears are fortunately very rare. This is where the tear extends into the anal or rectal mucosa.

Episiotomy

An episiotomy is a cut that mimics a second-degree tear. If there is not a working epidural, then the perineum is injected with local anaesthetic prior to the episiotomy. An incision is made from the vaginal mucosa and down the perineum, curving the incision away from the anorectal area.

Episiotomy is not routine. If the baby’s head has been stretching the perineum for several contractions, but not advancing, an episiotomy may be preferable to multiple tears or a severe tear. If baby’s head is close to delivery and baby’s heart rate is down, an episiotomy may be needed to expedite delivery for the sake of baby’s wellbeing. After an episiotomy, baby may be delivered in two minutes rather than waiting twenty minutes for the perineum to slowly stretch to allow delivery. If vacuum or forceps delivery is required, due to inadequate progress with pushing or fetal distress, an episiotomy will allow delivery of the head more quickly than waiting several contractions for the perineum to stretch.

Repair of the perineum

If there is not an epidural, local anaesthetic is injected into the perineum for suturing. The epidural or local will take away any feeling of sharpness but touch and movement will be felt. There may be some soreness like having a bruise touched. Nitrous gas may be used to decrease the sensation of local anaesthetic injection and suturing.

Some sutures are placed in the mucosa of the vagina. There are some sutures deep to the perineal skin to rejoin the perineal muscles and then subcuticular stitches underneath the perineal skin to finish the repair. Repair in layers takes longer but avoids leaving knots on the outside which would be irritating as healing occurs.

At the end of the repair there will be one knot inside the vaginal which will fall out within a few weeks and the other suture material will dissolve. Initially the subcuticular stitches under the skin leave a small gap in the surface of the skin similar to a paper cut. This may cause the occasional twinge of discomfort like a paper cut but by two weeks postpartum the top layer of skin will be sealed together.

Third degree tears require special repair of the sphincter muscle prior to repair of the perineum. The sphincter muscle will heal well providing that infection and constipation are avoided. The scar tissue in the sphincter muscle is like a knot in a rubber band with the preservation of the elastic nature of the muscle. It is rare that there is any difficulty in controlling passage of flatus or faeces after repair of a third degree tear.

As a fourth degree tear involves the anorectal mucosa and the internal anal sphincter, repair is often carried out in association with a Colorectal Surgeon. Avoidance of infection and constipation afterwards is also necessary. As the fourth-degree tear is associated with more risk of altered bowel function it would be recommended to avoid a subsequent vaginal delivery after fourth degree tear because of the small risk of further damage.

The vast majority of tears heal very well. In subsequent vaginal deliveries the chance of having sutures is halved to around 30%. Sometimes the scar tissue will split but these tears are usually shorter and more superficial. The risk of having another third degree tear after a previous third degree tear is less than 15%. Given the good healing of these tears is not necessary to avoid vaginal delivery after a third degree tear.

Postpartum

Postpartum the perineum will be sore from bruising and increasing swelling. Swelling in the lower half of the body increases after delivery and peaks around Day 4 postpartum. Between the first and second weeks postpartum, the swelling will resolve. Ice packs are provided to apply to the perineum for the first few days postpartum which will help minimize bruising and swelling. Otherwise the perineum should be kept clean with at least one shower daily and pads changed frequently.

With breastfeeding the oestrogen levels are low in order to maintain milk production. Low oestrogen levels result in symptoms of a tight, dry vagina which may cause discomfort with intercourse. Women often blame having the perineum sutured for these symptoms but women who have caesarean sections also have these symptoms. Topical oestrogen cream can be applied to the oestrogen deficient vaginal and vulval area to reduce these symptoms.