women (N = 486) worked normal shifts and hours in their assigned jobs (Thomas et al., 1991). There was some evidence that pregnant women would be transferred off ships before 20 weeks. Frequently mentioned hazards included toxic chemicals, fuels, fumes from paints, and other products. Less frequently mentioned hazards were noise, x rays, electric shock, and radiation.

The risk of radiation exposure of the fetus during high-altitude or space flight poses the single biggest medical concern in allowing women access to all aviation and space careers. Orthostatic intolerance during flight may contribute to lower gravitational tolerance during pregnancy. There is a chance of incapacitation due to spontaneous abortion, nausea and vomiting, weight gain, and unsteadiness. Spontaneous fetal loss was increased in flight attendants compared with the general population (relative risk, RR = 1.9) (Lyons, 1992).