Shoulder dystocia can happen when:
- A baby is unusually large. Overweight women and women with diabetes are at risk for having large babies.
- The mother's pelvic opening is too small for the baby's shoulders to come out.
Although there are risk factors for shoulder dystocia, health care providers cannot usually predict or prevent it. They often discover it only after labor has begun.
A pregnant woman may be at risk for shoulder dystocia if:
- Her baby is very large. (But in most cases of shoulder dystocia, the baby's weight is normal. And for most very large babies, shoulder dystocia doesn't occur.)
- She has diabetes.
- She is pregnant with more than one baby.
- She is obese.
- She delivers after the baby's due date.
- She has had shoulder dystocia or a very large baby during a past delivery.
Shoulder dystocia may occur when the woman has no risk factors.
What happens in the delivery room
In most cases, the baby is delivered safely. Here are some things that may be done:
- Pressing the mother's thighs against her belly.
- Applying pressure to the mother's belly.
- Rolling the mother onto all fours.
- Turning the baby's shoulder while it is still inside the mother.
- Gently cutting a wider opening in the woman's vagina (an episiotomy).
- Performing a cesarean section after labor has begun. Because shoulder dystocia is hard to predict, a planned c-section is usually not recommended to prevent it.
Usually, the mother and the baby do well and have no permanent damage. But there may be some complications. For the baby, risks include:
- Injury to the nerves of the shoulder, arms and hand. This may cause shaking or paralysis. In most cases, the problems go away in 6 to 12 months.
- A broken arm or collarbone.
- Lack of oxygen. In the most severe cases, which are rare, this can cause brain damage and even death.
Complications for the mother include:
- Heavy bleeding after delivery
- Tearing of the uterus, vagina, cervix or rectum
- Bruising of the bladder
In most cases, complications can be treated and managed.