Depending on your position and work environment, you might have to alter your duties temporarily or request a change in location or accommodations. If your job involves any of the following conditions, talk with your human resources department about your options:

Weight lifting. Lifting heavy packages, boxes, or other items is not recommended in pregnancy, especially past week 20 (for example, shipping and receiving clerks, warehouse work).

Secondhand smoke. Women who work in the hospitality industry (for example, bartenders, waitresses) expose their fetus to toxins in secondhand smoke.

High heat. Excessive temperatures can be harmful to fetal development, particularly in the first trimester (for example, summer construction, factory environment).

Teratogen exposure. Jobs that involve working with certain chemicals and hazardous substances (for example, welders and lead exposure, dry cleaners and benzene exposure) are linked to birth defects.

Standing and repetitive movement. Line work or other jobs that keep you on your feet all day (for example, factory jobs, assembly work, piece work) can exacerbate circulatory problems.

Ionizing radiation exposure. Pregnant pilots and flight crew may be exposed to excessive ionizing radiation, another known teratogen. Radiographic imaging technicians who work with X-rays, CT scanning equipment, and nuclear medicine are also at risk.