Many expectant mothers need medication during pregnancy for one reason or another. For the health of your child, please pay attention to the effects of different drugs on the fetus. The U.S. Food and Drug Administration (FDA) classifies drugs into five categories based on their different degrees of teratogenic risk to animals and humans, called the pregnancy classification of drugs, or FDA classification for short. category A: drugs used during early pregnancy that have not been seen to be harmful to the fetus in controlled clinical studies and whose risk is minimal, such as multivitamins. category B: drugs that have not been seen to be harmful to the fetus in animal studies, but for which controlled clinical studies are lacking; or Harmful to the fetus has been observed in animal experiments, but has not been confirmed in clinical controlled studies. The fetus is not affected by these vitamins, but there are no controlled studies in humans. Class D: If there is evidence of harm to human fetus, but there is no clinical alternative, it should be used after weighing the pros and cons. Class X: The harmful effects of these drugs on animals and humans far outweigh any beneficial effects they may have, and their use during pregnancy is contraindicated. Such as anti-cancer drugs, birth control pills, etc.