PP-011 A comparative review of guidelines on macrosomia and shoulder dystocia

The aim of this study was to review and compare the most recently published influential guidelines on the diagnosis, prevention and management of fetal macrosomia and shoulder dystocia, which are both associated with adverse pregnancy outcomes.

A comparative review of guidelines from the American College of Obstetricians and Gynecologists, the Royal College of Obstetricians and Gynecologists, the National Institute for Health and Care Excellence, the Royal Australian and New Zealand College of Obstetricians and Gynaecologists and the Department for Health and Wellbeing of the Government of South Australia on macrosomia and shoulder dystocia was conducted.

The American and the Australian College of Obstetricians and Gynecologists agree that macrosomia should be defined as birthweight above 4000-4500g regardless of the gestational age, while the National Institute for Health and Care Excellence defines macrosomia as an estimated fetal weight above the 95th percentile. According to the first two medical societies, ultrasound scans and clinical estimates can be used to rule out fetal macrosomia, although lacking accuracy. Exercise, appropriate diet and pre-pregnancy bariatric surgery are mentioned as preventive measures. It is unanimously discouraged to routinely induce labor before 39 weeks of gestation with the sole indication of suspected fetal macrosomia, but an individualized counseling should be provided. There is also agreement among the reviewed medical societies concerning the definition and the diagnosis of should dystocia with the “turtle sign” being the most frequent sign for its recognition as well as the poor predictability of the reported risk factors. In addition, there is consensus on the algorithm of shoulder dystocia management with McRoberts technique suggested as first-line maneuver. Moreover, all guidelines agree that appropriate staff training, thorough documentation and time keeping are crucial aspects of shoulder dystocia management. As for the prevention, the American and the Royal College of Obstetricians and Gynecologists recommend elective caesarean section in case of an estimated fetal weight above 4500g or 5000g for diabetic and non-diabetic women, respectively, while the Department for Health and Wellbeing of the Government of South Australia is against elective birth in non-diabetic women with suspected fetal macrosomia. 

Macrosomia is associated not only with shoulder dystocia but also with maternal and neonatal complications. Similarly, shoulder dystocia can lead to permanent neurologic sequalae as well as perinatal death if managed in a suboptimal way. Therefore, the development of consistent international practice protocols for their prompt diagnosis and effective management is of paramount importance in order to safely guide clinical practice and improve pregnancy outcomes.