Pregnant and breastfeeding women get a lot of advice from just about everyone on just about everything– what to eat, medications to avoid, how much exercise they should do. When it comes to their jobs, though, the advice seems to dry up. That’s because occupational exposure limits are based on studies of healthy, non-pregnant workers and many early studies of occupational hazards were limited to men. These recommended exposure limits might not be sufficient to protect a developing fetus. We are trying to find out whether things people were exposed to at work like chemicals, noise, shift work, radiation, or germs affect their pregnancy outcomes and health of their children. One of the outcomes we study is birth defects.