Labor & Delivery: Risk Factors for Tears Health Article

Risk Factors for Vaginal Laceration

The following factors are associated with an increased risk of vaginal or cervical laceration:

• A woman's first vaginal delivery. The most common risk factor for vaginal laceration is nulliparity (the condition of never having delivered a baby). The tissues at the vaginal opening are tense and tight prior to delivery; however, as the baby descends through the birth canal, the tissues steadily stretch and soften, making them more pliable. Once a mother has delivered a child vaginally, future deliveries will be less likely to cause vaginal trauma.
• A large baby. The larger the baby, the more the cervix and vagina must stretch to allow delivery. Therefore, larger babies result in more tears. Women who are at increased risk for shoulder dystocia (childbirth complicated by wide shoulders in the baby), such as those who have diabetes, are at increased risk for vaginal injury or episiotomy.
• Abnormal position of the baby's head. When the baby's head is in a position other than the normal face down position (for example, if the baby is in face-up or breech position), the risk for vaginal injury is increased.??Forceps or vacuum-assisted vaginal delivery. Assisted vaginal deliveries are associated with increased vaginal tearing. The vacuum extractor is associated with fewer vaginal injuries than forceps, because the vacuum extractor does not require a wide passage through the birth canal. In addition, since there is less force produced by the vacuum extractor, delivery occurs more slowly and tends to cause less trauma to the vagina. Forceps-assisted deliveries are more likely to be complicated by vaginal wall tears and third or fourth degree vaginal lacerations.
• Forceps or vacuum-assisted vaginal delivery. Assisted vaginal deliveries are associated with increased vaginal tearing. The vacuum extractor is associated with fewer vaginal injuries than forceps, because the vacuum extractor does not require a wide passage through the birth canal. In addition, since there is less force produced by the vacuum extractor, delivery occurs more slowly and tends to cause less trauma to the vagina. Forceps-assisted deliveries are more likely to be complicated by vaginal wall tears and third or fourth degree vaginal lacerations.

Preventing Vaginal and Cervical Injuries

Patience is the key to avoiding serious vaginal or cervical trauma during labor. The majority of cervical injuries can be avoided by delaying pushing until the cervix is completely dilated. The same is true for vaginal tears. If the delivery occurs in a controlled fashion, with the baby's head descending slowly and steadily through the vaginal opening, the risk of vaginal trauma is greatly diminished. When there is no evidence of fetal distress, it may be beneficial to permit the baby's head to rest at the vaginal opening for several minutes to allow adequate stretching and distention of the tissues.

Warm compresses (wash cloths soaked in warm water) applied to the vaginal opening and gentle massage of the vaginal tissue may also help the stretching process. However, too much massage may result in swelling and increased vaginal tearing.

Vaginal tears may occur even when great care is taken to avoid them. Unfortunately, there is no reliable method for preventing vaginal trauma.

For more information about cervical and vaginal tears, go to Labor & Delivery: Treatment for Vaginal Tears and Labor & Delivery: Complications From Vaginal Tears.