Types of Spontaneous Vaginal Tears
The most common injuries to the vagina during labor occur at the vaginal opening, which may tear as the baby's head passes through. For successful vaginal delivery, the vaginal opening must dilate to at least 10 centimeters. When this occurs slowly, the tissues are pliable enough to allow appropriate stretching. However, when the baby descends quickly, the tissues can tear. Lacerations of the vaginal opening most often occur in the midline in either the posterior aspect (the 6 o'clock position-the part of the vagina closest to the anus) or in the anterior aspect (the 12 o'clock position-the part nearest the urethra or clitoris).
Degrees of vaginal tears:
- First degree tears involve only the lining or mucosa of the vagina.
- Second degree tears involve the vaginal lining and the deeper (submucosal) tissues but do not involve the anal sphincter or rectum.
- Third degree tears extend from the vaginal lining through the anal sphincter but do not involve the rectal lining.
- Fourth degree tears include the vaginal lining, submucosal tissues, anal sphincter, and rectal lining.
Tears that occur in the posterior portion of the vagina can be of varying severity. When the tear involves only the lining of the vagina, it is classified as a first degree laceration. First degree lacerations are the most common. A first degree tear may not bleed and may not require repair. When the tear extends into the submucosal tissues (the tissues just under the vaginal lining), it is referred to as a second degree laceration. Most second degree tears occur in the midline and extend towards the anus. All second degree lacerations require surgical repair.
More serious lacerations involve the deeper tissues, including the anal sphincter (third degree lacerations) or even the rectum and its lining (fourth degree lacerations). These lacerations are often difficult to repair and require a skilled surgeon. Third and fourth degree tears are more likely to be associated with complications, including infection, bleeding, anal incontinence, and increased pain.
Tears in the anterior area of the vaginal opening may involve the labia (the lips of the vagina) and the area around the clitoris. Most often, these lacerations are small, but they may be very painful because they are located in very sensitive areas. When a tear is not bleeding significantly, repair is not required. Lacerations can occur near the urethra; when these tears are repaired, care must be taken to avoid damaging the urethra during repair. This can be accomplished by inserting a plastic tube called a catheter into the opening of the urethra.
Occasionally, the vaginal wall may tear. These injuries are usually due to use of forceps during delivery and occur on the side of the vagina well above the vaginal opening. It is very important to identify these injuries, as they may result in significant blood loss if left untreated. These types of tears are easily repaired.