Study Reveals Inducing Labor May Prevent Shoulder Dystocia

Fetal macrosomia and large for gestational age status are linked to an increased risk of neonatal and maternal complications, such as emergency cesarean section and shoulder dystocia. While early term induction and prophylactic cesarean delivery have been thought to prevent complications during delivery and continued fetal growth, neither is recommended as a routine route for pregnant women who may have fetal macrosomia.

In a previous Cochrane review of three randomized trials, no significant reduction in the risk of shoulder dystocia was found when labor was induced, but the findings were limited by the small number of trials conducted and because as most of the women were at more than 40 weeks gestation. A more recent randomized trial weighed labor induction verses expectant management in 822 pregnant women with a singleton fetus aged 36 to 38 weeks, with an estimated weight greater than the 95th percentile for gestation age.

Shoulder dystocia is a labor complication that occurs when the baby’s shoulders do not deliver after the head has emerged. One or both shoulders become lodged against the mother’s pelvis. When this occurs, it almost always takes place during vaginal birth after a gestation period of 34 weeks or more.

Inducing labor may limit or prevent shoulder dystocia

The main outcome was a combination of substantial shoulder dystocia, long bone or clavicle fractures, intracranial hemorrhage, brachial plexus injury or even death. Cases of significant shoulder dystocia were classified as issues delivering the shoulders that could not be resolved by employing the McRoberts maneuver — typically combined with suprapubic pressure or births with more than a 60 second interval between the delivery of the head and the rest of the body. In total, labor induction took place in 89% of women randomized to induction, compared with 28% in the expectant management group.

When individual outcomes were analyzed, it was determined that labor induction was linked to a decrease in shoulder dystocia. Additionally, labor induction is also associated with the risk of increasing cesarean section rates, but during this trial, it was linked to a rise in spontaneous vaginal delivery and no major differences in the rates of cesarean sections or assisted vaginal deliveries. No substantial differences were noted in other maternal adverse outcomes or in rates of neonatal fractures. Additionally, no cases of intracranial hemorrhage, brachial plexus injury or neonatal death were noted.

Slow recruitment led to the early termination of the trial — only 822 women were enrolled out of an intended 1,000 — but this was still much larger than previous studies. Other trials have found increased morbidity in a large group of infants delivered electively at 37 to 39 weeks, but there was no subcategory of babies who were large for their gestational age. In total, the new results indicate that inducing labor may be the best option in early term babies who are believed to have macrosomia.

Birth trauma associated with shoulder dystocia

Shoulder dystocia can cause complications for both the mother and her child. In most cases, no permanent damage will be done, but serious and lasting injuries are possible. The child may suffer an injury to the nerves of the arms, hand and shoulder. This can cause shaking or paralysis that typically lasts from six to 12 months.

It can also cause the baby to suffer a lack of oxygen to the brain, which can cause brain damage and even death in the most severe instances. The mother may suffer heavy bleeding after birth and tearing of the rectum, vagina, cervix or uterus — most of which can be treated and managed.

Resources Resources