What proportion of birth weight is attributable to maternal glucose among infants of diabetic women?

Objective: This study was undertaken to determine the proportion of birth weight attributable to glucose concentrations of diabetic mothers.

Study Design: Data of diabetic women who used insulin were eligible for analysis if the women had been treated during pregnancy for at least 12 weeks, and had recorded at least 50% of 4 daily glucose checks (fasting and 1-hour postprandial) until the last office visit before delivery. The independent association between maternal glucose values and demographics and birth weight percentiles for gestational age and gender were analyzed by multiple regression methods.

Results: Data of 90 diabetic women were analyzed. Only third-trimester glucose concentrations were associated with birth weight. Prepregnancy body mass index was also selected in the models, including second- and/or third-trimester glucose. Together, these variables explained 18% of the variance in birth weight percentiles.

Conclusion: Maternal glycemia during third-trimester and prepregnancy body mass index are independent predictors of birth weight in pregnancies complicated by insulin-requiring gestational or type 2 diabetes.