Shoulder dystocia is a medical emergency that occurs when one or both of a baby’s shoulders get stuck during vaginal delivery. Attempts at delivery can result in fractures of the baby’s collarbone or arm and damage to the nerves in the shoulders, arms, and hands. In severe cases, lack of oxygen during the birth process can lead to brain damage or death. Shoulder dystocia also can cause maternal complications, such as tears and bleeding.
There is no established method to reliably predict shoulder dystocia, which occurs in 0.2% to 3% of deliveries. Excessive fetal growth and maternal gestational diabetes are considered risk factors for the condition, but only a minority of cases occur among large newborns and infants of mothers with diabetes.
Scientists from the Epidemiology Branch and colleagues assessed relationships between fetal and maternal characteristics and the occurrence of shoulder dystocia among Fetal Growth Study participants considered at low risk for the condition. Their analysis included 1,714 women who delivered vaginally, of whom 23 (1.3%) experienced shoulder dystocia.
Their findings confirm the unpredictability of shoulder dystocia among women at low risk. While the scientists identified links between certain fetal measurements and shoulder dystocia, these relationships could not be used individually, or in combination, to reliably predict the condition. Among maternal characteristics, only the use of epidural anesthesia during labor was more common among women who experienced shoulder dystocia than those who did not.
The authors note that these findings support existing guidance for clinicians to anticipate the possibility of shoulder dystocia with every delivery and be prepared to effectively manage it.
Learn more about the Division of Population Health Research (DiPHR): https://www.nichd.nih.gov/about/org/dir/dph