The modified Pedersen’s hypothesis explaining the pathophysiology of
macrosomia. When maternal glycemic control is impaired and the maternal
serum glucose level is high, glucose crosses the placenta – but insulin
does not. In the second trimester, the fetal pancreas responds to hyperglycemia
and secretes insulin in an autonomous manner (hyperinsulinemia).
The combination of hyperinsulinemia and hyperglycemia leads to an increase
in protein and fat stores in the fetus, resulting in macrosomia.