The relationship between pregnancy weight gain and glucose tolerance status among black and white women in central North Carolina

Objective The objective of the study was to examine weight and its relationship to glucose intolerance during pregnancy. Study design Women were classified into mutually exclusive glucose tolerance groups; impaired glucose tolerance of pregnancy defined as 1 high value on the oral glucose tolerance test, gestational diabetes mellitus as 2 high values, and normal glucose tolerance as a normal value on the universal screen test. Logistic regression was used to examine the relationship between prepregnancy body mass index and weight gain, and glucose tolerance status and predicted probabilities were calculated. Results Weight gain ratio (observed/expected) was significantly higher for women with gestational diabetes mellitus, compared with women with normal glucose tolerance. The likelihood of developing gestational diabetes mellitus was significantly increased by both prepregnancy overweight (odds ratio 2.2, 95% confidence interval 1.1-4.3) and obese status (odds ratio 3.7, 95% confidence interval 2.2-6.3) but only marginally by weight gain ratio. In contrast, the likelihood of developing impaired glucose tolerance was increased by weight gain ratio for women who started pregnancy overweight. Conclusion Prepregnancy weight was strongly associated with gestational diabetes mellitus, whereas weight gain during pregnancy was associated with impaired glucose tolerance only among overweight women.