We examined the association between work during pregnancy and pregnancy-induced hypertension in a prospective cohort study of 717 women. We classified cases, whom we identified by uniform review of blood pressures and proteinuria in prenatal records, into two categories: gestational hypertension (N = 16, 2.5%) and preeclampsia (N = 11, 1.7%). All cases of pregnancy-induced hypertension occurred among the 575 subjects who worked during the first trimester of pregnancy. The association with employment was not explained by primiparity or other known risk factors, or by physical work demands, long work hours, or total hours of paid work, housework, and child care. Stressful job characteristics, however, did show associations with pregnancy-induced hypertension. In particular, gestational hypertension was associated with low decision latitude and low job complexity among women in lower-status jobs [standardized odds ratio (SOR) = 2.4 for low latitude, 95% confidence interval (CI) = 1.1-5.2; SOR = 2.1 for low complexity, 95% CI = 1.0-4.6]. Among women in higher-status jobs, gestational hypertension was associated with job pressures/low control (SOR = 3.6, 95% CI = 0.9-15.1). Psychosocial job stressors, not studied previously, might explain earlier reports of a raised risk of pregnancy-induced hypertension among pregnant workers.