Can women have birth defects or anything bad if they get a virus?

Depends on virus: Some localized viral issues like colds are very limited in their penetration into the body & don't have a blood phase. These are unlikely to affect a fetus.Those that have a blood phase, like german measles, can cause fetal loss, hearing & vision loss, cataracts & more. Effect is often influenced by the timing (before or after organs finished forming) & aggressive nature of the virus.