Objective: To examine the risk of developing gestational diabetes mellitus (GDM) in women with twin compared with singleton pregnancies.
Research design and methods: We examined a cohort of 23,056 pregnant women who gave birth to a live infant between 1 September 1998 and 31 December 2006, 553 of whom had twin pregnancy. The primary exposure was twin versus singleton pregnancy, and the primary outcome was the development of GDM. Standard univariate analyses were performed, as were multivariable analysis with logistic regression to control for potential confounding variables. GDM was diagnosed using criteria of the National Diabetes Data Group.
Results: Patients with twin pregnancies had a higher rate of GDM when compared with singleton pregnancies (3.98% vs. 2.32%; p = 0.01). In a multiple regression analysis after adjusting for age, race/ethnicity, body mass index, maximal systolic and diastolic blood pressure, smoking and parity, twin pregnancy was associated with an approximately two-fold increase in risk for developing GDM (OR 2.2, 95% CI 1.4-3.6). In a stratified analysis, women between the ages of 25 and 30 years and African-American women had the highest risk of developing GDM in twin pregnancies. When compared with twins of non-diabetic mothers, twins of gestational diabetics had a higher rate of admission to the neonatal intensive care unit (37%vs. 52%; p = 0.05), had longer hospitalisation (8 +/- 0.5 vs. 16 +/- 4 days; p = 0.01) and higher rate for respiratory distress syndrome (7% vs. 27%; p = 0.001).
Conclusion: There is a significant increase in the incidence of GDM in twin pregnancies versus singleton pregnancies. The risk is highest in African-American and young women.