teratology

Teratology is the branch of medicine and biology that studies congenital anomalies—structural or developmental abnormalities that arise during prenatal development. The term derives from Greek teratos, “monster,” and -logy, “study of.” Teratology investigates the causes, mechanisms, and outcomes of abnormal development in humans and other organisms, integrating embryology, genetics, obstetrics, pediatrics, and toxicology.

Causes of developmental abnormalities are diverse and include genetic factors, environmental exposures known as teratogens, maternal health conditions, and interactions between these influences. Teratogens encompass drugs (for example, certain medications and their dosages), infections during pregnancy, chemicals, radiation, and nutritional deficiencies. The risk and type of malformation depend on the timing of exposure relative to developmental stages, especially during organogenesis. Outcomes span a spectrum from minor anomalies to major congenital malformations, growth restriction, functional deficits, or fetal loss.

History and practice: formal teratology emerged from early embryology and clinical observations, with a major catalyst in the mid-20th century and the thalidomide tragedy, which spurred changes in drug regulation, prenatal screening, and public health policy. Today teratology informs risk assessment, pregnancy counseling, preventive strategies, and regulatory frameworks; it also underpins preclinical testing and surveillance programs to identify and mitigate teratogenic risks.

Methods and scope: research uses animal models, in vitro systems, epidemiology, and genetics to understand mechanisms of disrupted development. Model organisms and cellular assays help elucidate pathways of morphogenesis, while human registries and cohort studies aid in documenting outcomes and refining prevention and management strategies.