Association of a woman's own birth weight with subsequent risk for gestational diabetes

Context Several studies have reported links between reduced fetal growth and subsequent risk for type 2 diabetes among older adults, but the association between indices of-fetal growth and gestational diabetes mellitus (GDM), a major complication of pregnancy and a strong predictor of type 2 diabetes, remains little explored. Objective To test the hypothesis that a woman's own fetal growth is inversely related to her later risk for GDM. Design and Setting Case-control study of linked hospital discharge and vital record data from the New York State Department of Health. Population Healthy women who completed their first pregnancies in New York State between 1994 and 1998 and who were also born in New York State, Records from each woman's first pregnancy were linked to those from her own birth (1970-1985). Cases were 440 women with a record of GDM. Controls were 22 955 remaining women with no indication of GDM. Main Outcome Measure A woman's own birth weight, alone and adjusted for gestational age. Results Birth weight showed a U-shaped relationship to a woman's risk of GDM in her first pregnancy, with the highest risks associated with low and high birth weights. Odds ratios (ORs) adjusted for gestational age were 2.16 (95% confidence interval [CI], 1.04-4.50) for birth weight of less than 2000 g and 1.53 (95% CI, 1.03-2.27) for a birth weight of 4000 g or more. Adjustment for potential confounding factors, particularly prepregnancy body mass index and maternal diabetes, increased the OR for low birth weight to 4.23 (95% CI, 1.55-11.51), but reduced the OR for high birth weight to 0.92 (95% CI, 0.54-1.57), leaving a strong inverse dose-response relationship between birth weight and risk of GDM (adjusted P for trend <.001). Conclusions In this large population-based study, a woman's own birth weight was strongly and inversely related to her risk of GDM, suggesting that early life factors may be important in the etiology of this disorder.