it is necessary to provide safer drug during the period of pregnancy , otherwise it may cause teratogenicity in the fetus . Teratogenic drugs: A teratogen is an agent that can disturb the development of the embryo or fetus. Teratogens halt the pregnancy or produce a congenital malformation (a birth defect). Classes of teratogens include radiation, maternal infections, chemicals, and drugs. this chart provide a clear idea about the drugs that can be used in pregnancy for endocrine system and renal system etc I've already done a detailed chart on safer drug choice in pregnancy , the link is available at last slide , this was prepared on my academic purpose ....... please comment thank u