Family history of diabetes mellitus as an independent risk factor for macrosomia and cesarean delivery

Objective.To test the association between familial history of diabetes mellitus and birth-weight as well as mode of delivery stratified for the presence of the disease. Methods.A population-based study, comparing birth outcome of patients with and without familial history of diabetes mellitus was conducted. Patients lacking prenatal care were excluded from the analysis. Multiple logistic regression models were used to control for confounders. The MantelHaenszel procedure was used to obtain the weighted odds ratios while controlling for the presence of diabetes mellitus (either gestational or pre-gestational). Results.Out of 181,479 deliveries, 7.6% (n=13,813) were in patients with familial history of diabetes mellitus. These patients had higher rates of diabetes mellitus (either gestational or pre-gestational) as compared with patients without familial history of diabetes mellitus (13.7% vs. 6.3%, OR=2.3; 95% CI 2.2-2.5, p<0.001). Patients with familial history of diabetes mellitus had higher rates of macrosomia (birth-weight >4kg; 5.7% vs. 4.6%, p<0.001). Also, a 1.3-fold increase in the risk for cesarean delivery (CD) was found in patients with familial history of diabetes mellitus as compared with the comparison group (17.1% vs. 13.8%, p<0.001). Using two different multiple logistic regression models, one with CD and the second with macrosomia as the outcome variable, the association between familial history of diabetes mellitus and these complications remained significant (OR=1.2; 95% CI 1.1-1.2; p<0.001 and OR=1.2; 95% CI 1.03-1.2; p=0.005, respectively). The two models controlled for important confounders such as diabetes mellitus and the year of delivery, in order to control for ascertainment bias. Conclusion.Family history of diabetes mellitus has a significant, independent association with the risk for macrosomia and CD during pregnancy, regardless the presence of the disease.