What Happens to the Perineum During Birth
Every woman’s body has the amazing capacity to expand. The uterus – the size and a shape of a small pear before pregnancy – usually rests deep in the pelvis. By the end of pregnancy, it grows to just below the ribcage. The abdominal muscles and skin stretch to accommodate it.
The body releases hormones that allow the bony pelvis to give and shift so the baby can move through it once contractions start. The strong uterine muscles contract to thin and open the cervix fully.
Once that happens, the contracting uterus along with the strong pelvic floor muscles, work to push the baby into the birth canal – also known as the vagina – and eventually out into the world.
Your vagina - a 3 to 4 inch long stretch of elastic tissue - can expand 200 percent to during arousal and to accommodate a baby. Because the baby moves down slowly, a woman’s body has time to adjust and slowly stretch.
Depending on factors such as baby’s size and mom’s position, however, the perineum (the tissue between the vaginal opening and the anus) can get in the way of the birth.
One of three things can happen at this point. Supportive techniques can be used to help birth the baby’s head over the perineal tissue. Or, the tissue may give way – creating a small natural tear often referred to as perineum tear.
Or, the healthcare provider may cut the perineum to speed the process (or if instruments are needed to deliver the baby safely). This cut is called an episiotomy.
Perineal lacerations (which is the term for all tears and cuts together) are grouped by degrees depending on the tissues involved:
- First degree: tear in the skin layer only, typically does not need stitches and heals well naturally
- Second degree: tear of the skin and muscle layers, most common, may need minimal stitching
- Third degree: involves skin, muscle and anal sphincter, requires stitches
- Fourth degree: not only involves the skin, muscle, and anal sphincter but extends into the rectum, and requires extensive repair. This type is rare – only 1% of lacerations are fourth degree.
Episiotomy is more likely than a natural tear to result in a third or fourth degree laceration. Complications from episiotomy in the postpartum period include blood loss, pain and infection.
More long lasting problems related to an episiotomy include urinary and fecal incontinence and painful intercourse.
Thankfully, the rate of episiotomy in the Unites States has been dropping. In 2012, 12% of vaginal births had an episiotomy, down from 17% in 2006.
It’s possible to birth your baby with an intact perineum. According to researchers, the following methods can decrease perineal trauma:
- perineal massage (before and during the birth) decreases the severity of the laceration,
- application of warm compresses during pushing (by the birth attendant or the support person) decrease the risk for third and fourth degree lacerations, and
- using upright (standing, squatting, hands and knees) or side-lying positions for pushing, as opposed to supine or lithotomy (feet in stirrups) positions, decreases the incidence of episiotomy.
If you do have an episiotomy or tear, starting pelvic floor strengthening exercises as soon as you can after birth may speed healing. Wash the area with soap and water to prevent infection.
Witch hazel compresses and herbal sitz baths can provide temporary relief as the tissues heal. Having a bowel movement may be uncomfortable, so your provider may suggest a stool softener. Eating a high-fiber diet and drinking plenty of water can also help with this.
Protecting Your Pelvic Floor Starts Before Delivery
One of the best ways to protect your pelvic floor is to talk to your healthcare provider before the birth. Ask what his or her rates of perineal lacerations are. Ask under what conditions he or she would cut an episiotomy.
Ask what the provider can do to prevent tearing. Ask what you or your partner can do. Tell your doctor or midwife that you’d like to avoid an episiotomy unless absolutely medically necessary, and if you will be warned before you are cut.
You are the best advocate for your own body and your own health – if you don’t feel comfortable with your provider’s answers, this gives you the opportunity to discuss the issues or to change providers.
Exercise regularly, eat a healthy diet, don’t gain too much weight, and practice Kegel exercises throughout pregnancy. Read as much as you can about birth. Take childbirth preparation classes.
Knowledge about the realities of birth will empower you to find positions and comfort measures to achieve the birth you want – preferably without damage to the perineum or pelvic floor.
After twelve weeks of healing you can strengthen the pelvic floor if after childbirth by using a kegel exercise device. The Intimate Rose Kegel Exercise System is a six kegel weight system designed to progressively re-strengthen the pelvic floor muscles.
The weights are superior to kegel exercise balls because they are specifically designed with a woman’s body in mind, making them more comfortable and effective.
Strengthening the pelvic floor muscles is beneficial for addressing urinary incontinence (bladder leakage), or an overall feeling of looseness after delivery.
Aasheim V, Nilsen ABV, Reinar LM, Lukasse M. Perineal techniques during the second stage of labour for reducing perineal trauma. Cochrane Database of Systematic Reviews 2017, Issue 6. Art. No.: CD006672.
American College of Obstetricians and Gynecologists (ACOG). (2016). Practice Bulletin No. 165 Prevention and Management of Obstetric Lacerations at Vaginal Delivery. Obstet Gynecol. 2016 Jul;128(1):226-7.
Berkowitz LR, Foust-Wright CE. (2017) Approach to episiotomy. https://www.uptodate.com/contents/approach-to-episiotomy