ANNOUNCER: Amy Patterson from Fairfax, Virginia, asks: Why do women suffer morning sickness when they're pregnant?</s>ELIZABETH COHEN, CNN MEDICAL CORRESPONDENT: Well, the quick answer to that question is no one knows why pregnant women suffer from morning sickness, but there are a lot of theories. One prevailing theory is that the rapidly increasing amounts of hormones during the first trimester trigger nausea. There are also theories that changes in blood pressure and in a pregnant woman's digestive system may be the culprit. And there's one controversial theory that says morning sickness is actually nature's way of protecting the fetus. The idea here is that even just the sight of foods that could cause harm to the fetus makes a woman feel so sick she doesn't eat them. Since there are almost no studies on morning sickness, it's hard to say what the culprit is, but some scientists say chances are there's probably more than one cause.
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