Work, in general, does not increase the risks of pregnancy complications. Work that is stressful, physically, psychologically, or both, has deleterious effects on pregnancy. Stressful work increases the risks of miscarriage, preterm labor, preterm birth, low birth weight, and preeclampsia. The greater the stress, the greater the risks of pregnancy complications. Women with a history of pregnancy complications should be counseled about reducing stressful work before pregnancy. Women with stressful jobs should be followed closely during pregnancy, and if signs of preterm labor or delayed fetal growth develop, then occupational stress should be decreased or eliminated. Some occupations expose pregnant women to teratogens such as organic solvents, heavy metals, or pesticides. A careful work history should be part of every preconception and early pregnancy visit.