Abstract: Suspected fetal macrosomia is encountered commonly in obstetric practice. As birth weight increases, the likelihood of labor abnormalities, shoulder dystocia, birth trauma, and permanent injury to the neonate increases. The purpose of this document is to quantify those risks, address the accuracy and limitations of methods for estimating fetal weight, and suggest clinical management for a pregnancy with suspected fetal macrosomia.

Recommendations and Conclusions:

• The diagnosis of fetal macrosomia is imprecise. For suspected fetal macrosomia, the accuracy of estimated fetal weight using ultrasound biometry is no better than that obtained with clinical palpation (Level A).
• Suspected fetal macrosomia is not an indication for induction of labor because induction does not improve maternal or fetal outcomes (Level B).
• With an estimated fetal weight of greater than 4,500 g, a prolonged second stage of labor or arrest of descent in the second stage is an indication for cesarean delivery (Level B).
• Barring unusual circumstances, cesarean delivery should be performed for midpelvic arrest of the fetus with suspected macrosomia (Level B).
• As with clinical estimates of fetal weight, the true value of ultrasonography in the management of expected fetal macrosomia may be its ability to rule out the diagnosis, which may help to avoid maternal morbidity (Level B).

Reference: Fetal macrosomia. Practice Bulletin No. 173. American College of Obstetricians and Gynecologists. Obstet Gynecol 2016;128:e195–209.