THE INTERRELATIONSHIP BETWEEN ETHNICITY AND GESTATIONAL DIABETES IN FETAL MACROSOMIA

OBJECTIVE - To determine the possibility of an ethnic influence on the development of macrosomia (birth weight >90th percentile for gestatio nal age) in gestational diabetes mellitus (GDM). RESEARCH DESIGN AND M ETHODS - We prospectively followed all African-American and Latino wom en enrolled in the Temple diabetes-in-pregnancy program. GDM was diagn osed in 103 African-American and 36 Latino women during the study peri od (1991-1994) according to the criteria of Carpenter and Coustan. All women were treated according to our previously published protocols. D ata were collected on gestational weight gain, previous history of mac rosomia, body mass index (BMI), and level of maternal glycemic control . RESULTS - Insulin therapy was required in 53 women(37.5%) to maintai n fasting blood glucose levels at <95 mg/dl and 2-h postprandial level s at <120 mg/dl. Macrosomia developed in 50% of the neonates of Latino women versus 19% of neonates of African-American women (relative risk 2.68; 95% confidence interval 1.57-4.59). Potential confounding facto rs were not significantly different between the Latino and African-Ame rican women: mean blood glucose 96.6 +/- 15.7 vs. 96.5 +/- 22.4 mg/dl; BMI 29.0 +/- 5.5 vs. 31.5 +/- 8.2 kg/m(2) pregnancy weight gain 29.2 +/- 12.7 vs. 30.9 +/- 20.5 lb; and parity 1.8 +/- 1.5 vs. 1.6 +/- 1.4, respectively. CONCLUSIONS - We have demonstrated that Latino women wi th GDM are at higher risk for having macrosomic infants in comparison with African-American women. This ethnic variation in fetal growth may be due to varying influences of in utero growth promoters among these populations as well as underlying genetic factors.