What is shoulder dystocia?
Shoulder dystocia refers to the situation when, after the baby’s head emerges from the vagina, the shoulders fail to follow easily, either on their own with the mother’s pushing, or with some gentle assistance from the midwife or doctor. The word dystocia is derived from the Greek words meaning, literally, “not moving.” In other words, the shoulders are stuck. This situation is one of the most difficult for a midwife or doctor, no matter how skilled, and requires quick action and a series of maneuvers or steps to resolve. All midwives learn these maneuvers in their training and are ready to use them if needed. Usually, the first step taken is to flex the mom’s hips way back to open up the pelvis as wide as possible (called McRobert’s maneuver); the second step is to exert gentle but firm downward traction on the baby’s head; the third step is to have another person push down on the mom’s belly just above the pubic bone (to “unhook” the shoulder from behind this bone). After that, many midwives will ask the mom to flip over onto her hands and knees, which also “unhooks” the shoulder (called the Gaskin maneuver). If the baby is still not delivered, the midwife reaches in with her hand to try to turn the baby. Frequently, if these steps do not work the first time, they will work the second. Of course, the mom has to do her part by pushing forcefully when the midwife asks her to. One final maneuver (called the Gunn-Zavanelli-O’Leary maneuver) involves pushing the head back up into the vagina and delivering the baby by cesarean section. This is rarely used, but has saved some babies.
What causes shoulder dystocia and how can it be prevented? Risk factors for the mom include obesity, a previous large baby (greater than nine pounds) or baby that had shoulder dystocia, diabetes, or “advanced maternal age” (older than 35), excessive weight gain in pregnancy, short stature, abnormal pelvic shape or size, and postdates (going over two weeks past your due date). An estimated birth weight of over nine pounds, either with ultrasound or clinically (with the midwife using her hands to estimate the weight) are also risk factors. Of course, most moms with these conditions do not have shoulder dystocias with their babies, but they are more likely than other moms to have this happen. During labor, the suspicion of possible shoulder dystocia is raised by a long first stage (dilation stage), long second stage (pushing stage) with slow descent of the baby through the birth canal, or lots of molding or shaping of the baby’s head as he or she comes down. Most midwives will prepare for a possible shoulder dystocia if they know the mom has an increased risk or see these signs during labor. Preparing means having the mom in a good position to assist her if necessary, having help, and having resuscitation equipment ready if needed. (Babies who are stuck and require some extra minutes to get born frequently need a little extra jump-starting when they do come out.)