This is called an episiotomy and makes the opening of the vagina a bit wider, allowing the baby to come through it more easily. Sometimes a woman's perineum may tear as the baby comes out. An episiotomy can help to avoid a tear or speed up delivery. If your doctor or midwife feels you need an episiotomy when you're in labour, they will discuss this with you. Studies suggest that in first-time vaginal births, it's more common to have severe injuries involving the anal muscle if the perineum tears spontaneously rather than if an episiotomy is performed.