Final answer:
A woman contracting rubella during pregnancy can lead to birth defects and developmental issues in the fetus.
Step-by-step explanation:
The effect of a woman contracting rubella (or German measles) during her pregnancy can lead to birth defects and developmental issues in the fetus. Rubella is a teratogenic virus, meaning it can cause developmental defects if it crosses the placenta during pregnancy. The incidence of birth defects is highest if the mother is infected before 11 weeks of pregnancy, and decreases after that time.