What is shoulder dystocia during labor and birth?

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Paula Greer
Midwifery Nursing

Shoulder dystocia means that the baby’s head passes out of the birth canal and delivers but the shoulder of the baby gets stuck under the pubic bone. This is a medical emergency and requires special maneuvers to help the shoulder be able to come under the bone to safely deliver the baby. Certain conditions like diabetes and large babies may put the patient at risk for having a shoulder dystocia complicate their delivery. If you have a history or a previous shoulder dystocia with one of your births make sure to share this with your health care provider.

Shoulder dystocia occurs when the head emerges through the vagina, but the anterior shoulder of the infant cannot pass below the pubic symphysis, or requires significant manipulation to pass below the pubic symphysis. It is diagnosed when the shoulders fail to deliver shortly after the fetal head. There are some risk factors for shoulder dystocia, specifically related to fetal size and maternal pelvic opening size, however most cases of shoulder dystocia are discovered in the delivery room when the baby gets stuck. Shoulder dystocia is an obstetrical emergency, and creates risk for both mother and baby.

Charla Simon
OBGYN (Obstetrics & Gynecology)

Shoulder dystocia refers to when an infant's head delivers over the maternal perineum (spontaneously or assisted with vacuum or forceps) and then delivery of the anterior shoulder is difficult (or rarely impossible). The common reasons for this condition are excessive weight gain during pregnancy and maternal diabetes both of which can contribute to a large newborn. Other factors associated with should dystocia are multi-parity and advanced maternal age. 

There are many maneuvers available to assist the delivering obstetrician or midwife with the delivery and fortunately most of these episodes are brief and do not cause injury to the baby, however the longer it takes and the more maneuvers required the greater the risk of neurological injury and/or hypoxia to the neonate. 

In a small number of births (less than one in every one hundred), the baby's head is delivered but the shoulder gets stuck and the body does not come out quickly. This is called shoulder dystocia. It is an emergency situation because the baby can be deprived of oxygen, which, if the deprivation lasts for several minutes or more, can cause brain damage. Shoulder dystocia is more common when the baby is very big at birth (around ten pounds or more), but it can happen to smaller babies as well. It is also more common when the mother has diabetes during pregnancy. Babies born to women who have diabetes can be larger than average, and they tend to have bigger shoulders that are more likely to get stuck in the birth canal.

A health care provider will try to get the shoulder free through various maneuvers, including flexing the mother's thighs up against her abdomen, pressing on her abdomen just above the pubic bone, asking her to get into all fours position, delivering a posterior arm before the stuck shoulder, or trying to rotate the shoulder manually so it slips under the pubic bone. In some cases, shoulder dystocia is associated with broken bones and nerve damage in the arm. Most of the time, the arm will heal well and the baby will not have any problem. In rare instances, the baby can suffer long-term damage to the nerves in the arm. This injury can also occur in babies born by cesarean section, with and without labor. Shoulder dystocia is unpredictable, and there is no good strategy for preventing the associated complications.

Our Bodies, Ourselves: Pregnancy and Birth

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Our Bodies, Ourselves: Pregnancy and Birth

ALL THE INFORMATION YOU NEED TO MAKE WISE DECISIONS ABOUT YOUR PREGNANCY AND THE BIRTH OF YOUR CHILD -- FROM THE EDITORS OF THE CLASSIC "BIBLE OF WOMEN'S HEALTH" Pregnancy and birth are as ordinary...