Teratology

Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology caused by teratogens and also in pharmacology and toxicology. Teratogens are substances that may cause non-heritable birth defects via a toxic effect on an embryo or fetus.^[1] Defects include malformations, disruptions, deformations, and dysplasia that may cause stunted growth, delayed mental development, or other congenital disorders that lack structural malformations.^[2] These defects can be recognized prior to or at birth as well as later during early childhood.^[3] The related term developmental toxicity includes all manifestations of abnormal development that are caused by environmental insult.^[4] The extent to which teratogens will impact an embryo is dependent on several factors, such as how long the embryo has been exposed, the stage of development the embryo was in when exposed (gestational timing), the genetic makeup of the embryo, and the transfer rate of the teratogen.^[5][6] The dose of the teratogen, the route of exposure to the teratogen, and the chemical nature of the teratogenic agent also contribute to the level of teratogenicity.^[6]