embryotoxic

Embryotoxic is an adjective used in toxicology to describe substances, exposures, or effects that harm an embryo. Embryotoxicity refers to adverse outcomes during early development, including impaired growth, fetal resorption, or structural abnormalities. It is a component of reproductive toxicity and is related to, but not identical to, teratogenicity, which specifically denotes malformations that occur during development.

Embryotoxic effects depend on timing and dose. Early embryonic stages are often most sensitive to toxic insults, and the extent of harm frequently depends on the level and duration of exposure. In some cases, exposure may cause developmental arrest or reduced viability; in others, it may lead to malformations or functional impairment. The distinction between embryotoxicity and other developmental toxicities (such as teratogenicity) can be fluid, as some agents produce both embryotoxic and teratogenic effects depending on context.

Mechanisms underlying embryotoxicity are diverse. Substances can disrupt cell proliferation, differentiation, or apoptosis, interfere with signaling pathways, or impair placental development and nutrient transport. Oxidative stress, metabolic disruption, and interference with gene expression during critical windows of development are common avenues of harm.

Assessment and regulation: Embryotoxicity is evaluated through prenatal development studies in animals and through in vitro assays designed to model early development. Regulatory frameworks often require investigation of potential embryotoxic effects for drugs and chemicals, using a combination of in vivo and in vitro methods. Examples of such approaches include whole embryo culture techniques and embryonic stem cell assays, alongside standard animal reproduction studies.

See also: teratogenicity, teratogens, fetal development, reproductive toxicity.