Gestational diabetes is on the rise. The finding is not surprising given the dramatic increases in obesity and type 2 diabetes, but few studies have examined trends in gestational diabetes mellitus, reported Dana Dabelea, M.D., of the University of Colorado, Denver, and her associates.
The findings from Kaiser Permanente of Colorado's perinatal database include 36,403 pregnancies among 30,216 initially nondiabetic women who delivered singleton infants from 1994 to 2002 and had been screened at 24–28 weeks by the same protocol: a 1-hour 50-g oral glucose tolerance test, followed by a diagnostic 3-hour 100-g test in those with glucose values of at least 140 mg/dL on the 50-g test (Diabetes Care 2005;28:579–84).
A total of 1,183 pregnancies were complicated by gestational diabetes mellitus (GDM). The prevalence of GDM almost doubled—from 2.1% in 1994 to 4.1% in 2002. The rate increased by an average of 12% per year during that period.
The rise in GDM occurred in all ethnic groups, from 1.9% to 3.4% in non-Hispanic whites, 2.8% to 5.1% in Hispanics, 2.5% to 4.6% in African Americans, and 6.3% to 8.6% in Asians. However, throughout the study period, the combined prevalence of GDMin women of all the minority ethnic groups was consistently twice that of white women.
When broken down by the mother's birth period, the prevalence of GDM was about 40% higher for each successive birth decade from 1946 to 1990. This finding probably reflects women's exposure to increasing rates with time. Obesity is one of the strongest risk factors for GDM, the researchers said. Even in Colorado, with the lowest estimated prevalence of obesity of any state, obesity among women more than doubled from 1990 to 2001, they noted.