If the Dr sees the need for one, they will do it. I had an episiotomy with my first baby (13 years ago they did them routinely) He was only 7 lbs. I tore all the way down to my you know what bc of it too. The stitches and recovering were horrible. With my other two, the midwife said that out of 300 births, she had only done 3 and only bc they were emergencies. She said they don't do them bc of the increased risk of tearing through the sphincter or rectum. (which is exactly what I did) Episiotomy also increases the risk of infection. She advised me to do perineal massage before labor and she did it during labor as well. My My baby was almost 9 punds and I didn't tear, or need stitches. The recovery time was much easier.
Obstetricians used to do episiotomies routinely to speed delivery and to prevent the vagina from tearing, particularly during a first vaginal delivery, in the belief that the "clean" incision of an episiotomy would heal more easily than a spontaneous tear. Many experts also believed that an episiotomy might help prevent later complications, such as incontinence.
Many studies over the last 20 years have shown that this is not the case. In fact, there is no good evidence showing that episiotomy offers your vaginal tissue and pelvic floor muscles any real protection, and the procedure may actually cause problems. For this reason, the American College of Obstetricians and Gynecologists as well as a host of other experts now agree that the procedure shouldn't be done routinely.
I would avoid one if possible!!