What is the effect of poor maternal control in insulin-dependent diabetic mothers on their infants?

Poor maternal control of blood sugar levels in insulin-dependent diabetic mothers can lead to an increased risk of macrosomia in their infants. Macrosomia refers to a condition where the infant is significantly larger than average at birth, often defined as a birth weight of more than 8 pounds 13 ounces (4000 grams).

The underlying mechanism involves hyperglycemia (high blood sugar levels) in the mother, which can lead to excess glucose crossing the placenta into the fetal circulation. This excess glucose stimulates the fetal pancreas to produce more insulin, leading to accelerated growth and larger body size. The increased insulin levels can promote not only increased fat deposition but also stimulate growth of the organs, contributing to macrosomia.

Maintaining effective maternal blood glucose control is critical during pregnancy for reducing the risks associated with diabetes, including preventing macrosomia. Poor glycemic control is also associated with other adverse outcomes, including an increased risk of congenital malformations, but it is the direct effect of high maternal blood sugar that primarily contributes to macro-sized infants. Therefore, the association between poor maternal blood sugar control and the risk of macrosomia is well-established in obstetric care.