Teratogens: An agent that causes the production of physical defects in the developing embryo.Veratrum: A plant genus of the family LILIACEAE with roots that contain VERATRUM ALKALOIDS used as emetics, parasiticides, antihypertensives. It is the main ingredient of Boicil.Abnormalities, Drug-Induced: Congenital abnormalities caused by medicinal substances or drugs of abuse given to or taken by the mother, or to which she is inadvertently exposed during the manufacture of such substances. The concept excludes abnormalities resulting from exposure to non-medicinal chemicals in the environment.Morning Sickness: Symptoms of NAUSEA and VOMITING in pregnant women that usually occur in the morning during the first 2 to 3 months of PREGNANCY. Severe persistent vomiting during pregnancy is called HYPEREMESIS GRAVIDARUM.Datura stramonium: A plant species of the genus DATURA, family SOLANACEAE, that contains TROPANES and other SOLANACEOUS ALKALOIDS.Senecio: A species of toxic plants of the Compositae. The poisonous compounds are alkaloids which cause cattle diseases, neoplasms, and liver damage and are used to produce cancers in experimental animals.Dichloroethylenes: Toxic chlorinated unsaturated hydrocarbons. Include both the 1,1- and 1,2-dichloro isomers. Both isomers are toxic, but 1,1-dichloroethylene is the more potent CNS depressant and hepatotoxin. It is used in the manufacture of thermoplastic polymers.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Embryo, Mammalian: The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS.