The goal with a vaginal delivery is an intact perineum. This does not always happen. There can be tearing, the commonest area of tearing being the perineum. Hopefully it is only minor tearing.
Sometimes an episiotomy is needed. This could be to avoid a nasty perineal tear or if there is a forceps delivery. Sometimes the episiotomy extends so there is both an episiotomy and tear.
The diagram adjacent shows the stretched perineum with the baby’s head delivering and the usual direction of a tear.
Sometimes the anal sphincter muscle is traumatised and sometimes the tear goes completely from the vagina through to tearing the rectum skin (mucosa).
Classification of perineum tears
- First degree tear: tearing limited to the posterior entrance of the vagina (fourchette) and superficial perineal skin or vaginal mucosa (skin).
- Second degree tear: tearing also involves perineal muscles, but not the anal sphincter muscle.
- Third degree tear: tearing also of the anal sphincter muscle. Third degree tears may be further subdivided into three subcategories:
- Partial tear of external anal sphincter muscle involving < 50% thickness
- > 50% thickness tear of the external anal sphincter muscle
- internal anal sphincter muscle is torn.
- Fourth degree tear: tearing full thickness of anal sphincter muscle and also tearing of rectal mucosa (skin).
What are the implications of significant perineal trauma?
Short term possible implications
- A more uncomfortable perineum postnatally.
- Difficulty and pain passing urine and even urinary retention.
- Risk of perineal infection, bruising, breaking down, etc.
- Poor anal sphincter control and faecal incontinence.
Long term possible implications
- A more uncomfortable postnatal recovery.
- A gaping introitus.
- Vaginal flatus (“air trapping”)
- Dyspareunia (painful sex)
- Bleeding with sexual intercourse
- Poor anal sphincter control and faecal incontinence (if third or fourth degree tear).
- Deferring another pregnancy and especially another vaginal birth because of the unpleasant memories and fear (psychological as well as physical scarring).
What factors are important in determining your likelihood having significant perineal trauma:
- The elasticity of your perineal tissues.
- Prolonged pushing resulting in marked oedema of the tissues.
- The size of your baby especially of your baby and especially your baby’s head.
- Position of your baby’s head (whether occipito–anterior or occipito-posterior as it comes out through the entrance of your birth canal.
- Whether your baby’s head is well flexed or deflexed at delivery. A deflexed head means a bigger presenting diameter to deliver. This is common with an occipito–posterior position.
- Whether or not you have significant perineal scar tissue from a previous vaginal delivery. Scar tissue doesn’t stretch as well.
- The competence, experience and attitude of your accoucheur. The accoucheur is the person delivering your baby.
- The speed and control of delivery of your baby’s head.
- Whether you have an epidural. An epidural is associated with a less perineal trauma as it a more controlled slower delivery of the baby’s head. On the other hand some women find it much harder to push their baby out with an epidural and end up with an operative vaginal delivery as a consequence.
- Your position at delivery. Delivering on “all fours” or on your side will mean there is less pressure on your perineum.
- Whether or not you push your baby out. If you have an operative vaginal delivery, then whether you have a vacuum delivery or a forceps delivery. There is less perineal trauma and often no perineal trauma with a vacuum delivery. This is because the suction cap is attached to the top of your baby’s head and does not increase the stretch of the perineum. Also there is possibly more control of delivery of the head allowing a slower and more controlled stretch. Forceps, in contrast, are applied to the sides of the head and so by using forceps there is a greater diameter and greater stretching of the perineum. Forceps use usually means an episiotomy is done to minimise perineal trauma.
What can I do antenatally to avoid perineal trauma?
- Perineal massage is probably no use. There is no evidence I can find to prove it helps minimise the risk of perineal trauma.
- EPI-NO logically should help avoid perineal tears and also the likelihood of an operative vaginal delivery. I am personally not convinced and the scientific evidence is lacking. But using an EPI-NO won’t do harm.
What else can to avoid perineal trauma?
- Induction of labour to avoid baby getting too big, if there is evidence clinically and on ultrasound scan that you have a big baby.
- Slow controlled delivery of head of your baby with guarding of perineum and keeping baby’s head well flexed with delivery.
- An epidural.
- Vacuum rather than forceps, if operative vaginal delivery is needed.
- Avoid pushing too long in second stage.
- Delivering on “all fours” or on your side.
- Episiotomy if looks like very nasty tear will happen.
- Having the right accoucheur. There is more likelihood of perineal trauma if you are delivered by an inexperienced or poorly trained person.
- A Caesarean section delivery. Obviously there is no perineal trauma with a Caesarean section. Some women will request this and sometimes it will be recommended if there has been very significant perineal trauma with the previous vaginal delivery.
Improving recovery after perineal tearing
- Ice to perineum immediately after delivery.
- Adequate analgesia. Avoid codeine as it can constipate you.
- Avoid constipation and straining to open your bowels.
- While uncomfortable, sit on a ‘blow up’ ring to take pressure off perineum and put it on the buttocks area.
- Salt baths when you go home. This helps reduce swelling, is soothing and help with healing. Use a cup full of cooking salt in a low bath with luke warm bath. Sit in for less than 10 minutes. Repeat a few times in the day. Otherwise keep area clean and dry.
- Hair Blow dryer can help keep stitches dry.
- Clean area well after opening bowels.
- Rest. Have people visit you and your baby in first weeks you are home. Don’t rush around visiting them.