Merck Manual

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Shoulder Dystocia

By

Julie S. Moldenhauer

, MD, Children's Hospital of Philadelphia

Reviewed/Revised Jan 2024
VIEW PROFESSIONAL VERSION

Shoulder dystocia occurs when one shoulder of the fetus lodges against a pregnant woman’s pubic bone or sacrum during deliver, and the baby is therefore caught in the birth canal.

In shoulder dystocia, the head of the fetus delivers but the shoulder becomes lodged against the mother’s pubic bone or sacrum. Consequently, the head pulls back slightly into the vagina. The baby cannot breathe because the birth canal puts pressure on the chest and umbilical cord. As a result, oxygen levels in the baby’s blood decrease, and there is a risk of injury or death.

Shoulder dystocia is not common, but it is more common when any of the following is present:

When shoulder dystocia occurs, the doctor quickly tries various techniques to free the shoulder so that the baby can be delivered vaginally. An episiotomy Delivery of the baby Delivery of the baby (an incision that widens the opening of the vagina) may be done to help with delivery.

Shoulder dystocia increases the risk of problems and of death in the newborn. The newborn's bones may be broken during delivery, and the brachial plexus Plexus Disorders Plexuses (networks of interwoven nerve fibers from different spinal nerves) may be damaged by injury, tumors, pockets of blood (hematomas), or autoimmune reactions. Pain, weakness, and loss... read more (the network of nerves that sends signals from the spinal cord to the shoulders, arms, and hands) may be injured. The pregnant woman is also more likely to have problems such as

  • Excessive bleeding at delivery (postpartum hemorrhage)

  • Tears in the area between the vaginal opening and the anus

  • Injury of muscles in the genital area and nerves in the groin

  • Separation of the pubic bones.

NOTE: This is the Consumer Version. DOCTORS: VIEW PROFESSIONAL VERSION
VIEW PROFESSIONAL VERSION
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