The term "fetal macrosomia" is used to describe a newborn who's significantly larger than average. A baby diagnosed with fetal macrosomia has a birth weight of more than 8 pounds, 13 ounces (4,000 grams), regardless of his or her gestational age. About 9 percent of babies born worldwide weigh more than 8 pounds, 13 ounces. However, the risks associated with fetal macrosomia increase greatly when birth weight is more than 9 pounds 15 ounces (4,500 grams). Fetal macrosomia may complicate vaginal delivery and could put the baby at risk of injury during birth.
Fetal macrosomia also puts the baby at increased risk of health problems after birth. The pathophysiology of macrosomia is related to the associated maternal or fetal condition that accounts for its development. In general, poorly controlled diabetes, maternal obesity, and excessive maternal weight gain are all associated with macrosomia and have intermittent periods of hyperglycemia in common.
Fetal macrosomia is difficult to detect and diagnose during pregnancy. Possible signs and symptoms include:
Early delivery or elective Caesarian section are management options. Prognosis in a majority of cases is usually good.
Variation in the percentage of macrosomia in different ethnic groups has been observed independent of diabetes. In general, Hispanic women have a larger proportion of macrosomic newborns compared with white, African American, or Asian women. Male infants are more likely to be macrosomic than female infants.