Risk Factor Classifications
Federal agency of the United States Department of Health and Human Services on control of food and drugs (U.S. Food and Drug Administration; FDA) has developed the scale of possible risks for childbirth because of application of medicinal products by pregnant women, including the following categories:
Appropriate researches haven't revealed risk of an unfavorable effect on the foetus during the first trimester of pregnancy and there are no knowledge of risks in the second and third subsequent trimesters.
Experiments on animals haven't revealed risks of negative impact on the foetus. Pregnant women had no appropriate researches.
Experiments on animals have revealed negative impact of medicine on the foetus, but pregnant women had no appropriate researches. Nonetheless, the potential advantage connected with application of this medicine for pregnant women can justify its use, despite the available risk.
The evidence of risk unfavorable effect of medicine on the human foetus is obtained, however the potential advantage related to the application of medicine for pregnant women can justify its use, despite the risks.
This medicine isn't classified by FDA yet.
Violations of development of the foetus are revealed or there are proofs of risk of negative effect of this medicine for the human foetus, and, thus, risks for the foetus attached to such medicine exceeds possible advantage for a pregnant woman.