Non-diabetic macrosomia: an obstetric dilemma

Fetal macrosomia represents a continuing challenge in obstetrics, as it has risk of shoulder dystocia leading to transient or permanent fetal, maternal injury and medicolegal liability. The overall incidence of macrosomia has been rising. Non-diabetic macrosomia is still an obstetric dilemma, as there is no clear consensus regarding its ante-partum prediction and management, as accurate diagnosis is only made retrospectively. The risk of shoulder dystocia rises from 1.4% for all vaginal deliveries to 9.2-24% for birth weights more than 4,500 g. Unfortunately, 50% of all cases of shoulder dystocia occur at birth weights of less than 4,000 g. Brachial plexus injury occurs in 1:1,000 births and permanent damage in 1:10,000 deliveries (12% of all) leading to litigation 1:45,000 deliveries. The prenatal diagnosis of macrosomia remains imprecise. Pre-pregnancy and ante-partum risk factors and ultrasound have poor predictive value. Induction of labour and prophylactic caesarean delivery has not been shown to alter the incidence of shoulder dystocia among nondiabetic patients. Caesarean section and induction of labour are associated with increased risk of operative morbidity and mortality with added cost implications.