The purposes of the project are to determine the effects of abnormal glucose tolerance on outcome of the pregnancy, to determine long term prognosis for the women and their offspring, and to identify diabetes and impaired glucose tolerance during pregnancy in women in the Gila River Indian Community. By means of a glucose tolerance test as well as chart review, the diabetes status of women are determined at two-yearly intervals and during the third trimester of pregnancy. Offspring are followed from age 5 years and the effects of the diabetic intrauterine environment are evaluated in conjunction with other risk factors for obesity and diabetes. Glucose concentration measured 2 hours after a 75 g load in 60 young pregnant Pima women (age at pregnancy=18.2 years, range 12.4-27.2) was evaluated as a function of the glucose concentration measured in their mothers during pregnancy. Controlled for age and body mass index (BMI), a woman's 2-hour glucose was strongly associated with her mother's 2-hour glucose during pregnancy (p=0.003). Among women whose mothers had normal glucose tolerance the age- BMI-adjusted mean 2-hour glucose concentration (103.9+/-2.7 mg/dl; mean +/- s.e.) was significantly lower (p=0.012) than among those whose mothers had IGT and those whose mothers had diabetes (p=0.048). The latter two were not significantly different (p=0.831). During pregnancy glucose concentrations during an oral glucose tolerance test are strongly associated with the glucose concentrations measured in the mothers. Glucose concentrations among daughters of women with gestational IGT are just as high as among women with NIDDM and significantly higher than among the daughters of women with normal glucose tolerance.