What is the primary cause of macrosomia in pregnancies?

The primary cause of macrosomia is gestational diabetes. This condition leads to higher levels of glucose in the maternal bloodstream, which can cross the placenta, resulting in excessive fetal growth. The fetus then produces more insulin in response to the elevated glucose levels, further promoting increased fat deposition and overall size.

While obesity is indeed a significant risk factor for macrosomia and contributes to its occurrence through various pathways, including metabolic syndrome and insulin resistance, gestational diabetes is more directly linked as a primary causal factor. Hypertension and maternal age also play roles in pregnancy outcomes, but they are not primary drivers for macrosomia as gestational diabetes is.

Understanding the relationship between gestational diabetes and macrosomia is crucial for prenatal care, as management of blood glucose levels can significantly reduce the risk of fetal overgrowth.