linguistic:translation
Routes of Exposure

Harmful substances can enter a woman's body through breathing in (inhalation), contact with the skin, or swallowing (ingestion). Pregnant workers and those planning to become pregnant should be especially concerned about exposure to reproductive hazards. Some chemicals (such as alcohol) can circulate in the mother's blood, pass through the placenta, and reach the developing fetus. Other hazardous agents can affect the overall health of the woman and reduce the delivery of nutrients to the fetus. Radiation can pass directly through the mother's body to harm her eggs or the fetus. Some drugs and chemicals can also pass through a mother's body into the nursing baby through the breast milk.

Reproductive hazards do not affect every woman or every pregnancy. Whether a woman or her baby is harmed depends on how much of the hazard they are exposed to, when they are exposed, how long they are exposed, how they are exposed, and personal factors like age, stage of menstrual cycle, stage of pregnancy or when exposure occurs. For example, exposure to a hazard could block ovulation and pregnancy only at specific times of the menstrual cycle. Exposure during the first 3 months of pregnancy might cause a birth defect or a miscarriage. Exposure during the last 6 months of pregnancy could slow the baby's growth, affect its brain development, or cause premature labor.

Workplace substances that affect female workers and their pregnancies can also harm their families. Without knowing it, workers can bring home harmful substances that can affect the health of other family members—both adults and children. For example, lead brought home from the workplace on a worker's skin, hair, clothes, shoes, tool box, or car can cause lead poisoning in family members, especially young children.