Shoulder dystocia is when one or both of a baby's shoulders get stuck behind the mother's pubic bone after the head is already out of the birth canal. This can cause breathing problems, collarbone fractures, arm fractures, and injuries resulting in hand and arm deformities in the baby. Mothers may experience severe blood loss, tearing of the birth canal, and damage to the cervix and uterus.
This delivery problem generally occurs in only 0.6 to 1.4 percent of births. Babies with a birth weight of over 8 pounds, 13 ounces (about 4 kg) have a 5 to 9 percent chance of experiencing shoulder dystocia, with the risk increasing as birth weight increases. Mothers with diabetes are at a greater risk for shoulder dystocia as well. Often, the condition occurs without any advance warning or risk.
There are several maneuvers that doctors and midwives can perform to help dislodge the baby if shoulder dystocia occurs during the birthing process. No particular maneuver will work in every given situation, however, and often more than one maneuver often needs to be done to alleviate the problem. The maneuvers are usually performed in quick succession to minimize the risk of complications.
Suprapubic pressure can help dislodge babies stuck behind the pelvic bone by placing a firm pressure on the pubic bone to allow the shoulder room to move under the bone. This if often the first technique a doctor or midwife will employ to help a stuck baby move through the birth canal since it does not involve a change in the mother's position and does not involve any specific maneuver to be performed on the baby itself.
The Gaskin maneuver puts the mother on her hands and knees to change the width of the pelvis. This maneuver may not be possible if the mother has received an epidural, however.
The McRobert's maneuver involves the doctor or midwife pushing on the woman's feet to flex her legs toward her chest while she is lying on her back. This maneuver helps expand the pelvis, allowing the baby more room to move through the birth canal. The McRobert's maneuver is usually one of the most effective methods for relieving shoulder dystocia.
If the McRobert's maneuver is unsuccessful, the Woods maneuver can be used to turn the shoulders of the baby by pressing on the back of his or her shoulders. The Rubin maneuver involves pushing on the baby's shoulders in an upward motion toward the face to help the shoulders line up. The Zavanelli maneuver is the least used method because it is the most dangerous. This maneuver involves pushing the baby's head back inside the vagina to do an emergency cesarean section. Maneuvers that attempt to manipulate the baby are usually a last resort, since injury is more likely to occur.