Twin gestation ups risk of gestational diabetes mellitus

(HealthDay)—Twin gestation is associated with increased risk of gestational diabetes mellitus (GDM), according to an article published online May 23 in Diabetes Care.

Ravi Retnakaran, M.D., from Mount Sinai Hospital in Toronto, and Baiju R. Shah, Ph.D., from the University of Toronto, examined the impact of twin gestation and the sex of both fetuses on maternal risk of diabetes during and after pregnancy. A total of 775,707 women with singleton pregnancies and 13,521 women with twins (female/female, 31.7 percent; female/male, 36.0 percent; male/male, 32.3 percent) were included in the study.

The researchers found that per 100 pregnancies, the crude rate of GDM was 5.63 in twin gestation and 3.79 in singletons. The incidence of GDM was higher in twin pregnancies after adjustment for age, income, and region of residence (adjusted odds ratio, 1.30; P < 0.001). In twin gestation, the crude rate of GDM per 100 pregnancies was 5.56, 6.08, and 5.20 for female/female, female/male, and male/male twins. Neither male/male nor male/female carried greater risk of GDM than female/female in adjusted analyses. After adjustment for confounding variables, women who had GDM with twins had lower risk of progression to diabetes than those who had GDM with singletons (adjusted hazard ratio, 0.76; P = 0.001).

"Overall, these data suggest that the impact of the twin gestation itself on maternal glucose metabolism supersedes that of fetal sex," the authors write.