There are a few drugs that do not have any link with birth defects when taken by a pregnant woman. We say those drugs have little risk. Most drugs are between the two extremes of having great risk and little risk. Also, there are no studies of how most drugs affect pregnant women. As a result, we do not know if it is safe for a pregnant woman to take these drugs. Women who could get pregnant should talk with their doctor about any drugs they are taking. Together, they can decide if the benefit of the drug is worth the possible risk. If a woman finds out that she is pregnant while she is taking a drug, she should talk to her doctor soon. Some drugs are needed to keep the mother healthy. Not taking some drugs while she is pregnant may put both the woman's and her baby's health in danger. It is important for the woman and her doctor to talk about any drug she might need to take. The doctor can consider the woman's full medical history.