teratogen

teratogen /ter·a·to·gen/ (ter´ah-to-jen) any agent or factor that induces or increases the incidence of abnormal prenatal development.teratogen´ic

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te·rat·o·gen (t-rt-jn, tr-t-)

n.

An agent, such as a virus, a drug, or radiation, that can cause malformations or functional damage to an embryo or a fetus.

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Teratogen

Any substance, agent, or process that interferes with normal prenatal development, causing the formation of one or more developmental abnormalities of the fetus.

Mentioned in: Congenital Amputation, Congenital Bladder Anomalies, Fetal Alcohol Syndrome

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teratogen

[ter′ətəjen′]

Etymology: Gk, teras + genein, to produce

any substance, agent, or process that interferes with normal prenatal development, causing the formation of one or more developmental abnormalities in the fetus. Teratogens act directly on the developing organism or indirectly, affecting such supplemental structures as the placenta or some maternal system. The type and extent of the defect are determined by the specific kind of teratogen, its mode of action, the embryonic process affected, genetic predisposition, and the stage of development at the time the exposure occurred. The period of highest vulnerability in the developing embryo is from about the third through the twelfth week of gestation, when differentiation of the major organs and systems occurs. Susceptibility to teratogenic influence decreases rapidly in the later periods of development, which are characterized by growth and elaboration. Among the known teratogens are chemical agents, including such drugs as thalidomide, alkylating agents, and alcohol; infectious agents, especially the rubella virus and cytomegalovirus; ionizing radiation, particularly x-rays; and environmental factors, such as the age and general health of the mother or any intrauterine trauma that may affect the fetus, especially during the later stages of pregnancy. Also called teratogenic agent. Compare mutagen. teratogenic, adj.

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teratogen (t·raˑ·t·gn),

n a process, a substance, or an agent that interferes with regular, thus causing developmental abnormalities within a fetus. Examples include alkylating agents, thalidomide, and alcohol; infectious microbes like cytome-galovirus or the rubella virus; ionizing radiation such as x-rays; and environmental aspects such as the mother's age and overall health or trauma to the fetus during the gestational period.

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teratogen

an agent or influence that causes physical defects in the developing embryo.

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teratogen

Genetics Any agent, chemical, or factor that causes a physical defect in a developing embryo or fetus; maternal medications with known teratogenic effects include aminopterin–spontaneous abortion, malformations; anticoagulants; anticonvulsants; cytotoxic drugs; mepivacaine–bradycardia, death; methimazole & propylthiouracil-goiter; 131I–destruction of fetal thyroid; ♂ sex hormones–methyltestosterone, 17-α-ethinyl-testosterone, 17-α-ethinyl-19-nortestosterone–causes masculinization of ♀, tetracycline–hypoplasia and pigmentation of tooth enamel; trimethadione–abortion, multiple malformations, mental retardation; ♀ sex hormones cause virilization with defective external genitalia, transplacental carcinogenesis by DES. See Fetal warfarin syndrome, Fetal hydantoin syndrome, Thalidomide. Cf Litogen.