Introduction
Environmental factors play a crucial role in embryonic and fetal development, significantly influencing cellular processes, gene expression, and overall development. These factors include both external and maternal influences.
Teratogens:
- Teratogens are substances or agents that cause developmental abnormalities (teratogenesis) during critical periods of embryonic development.
- Drugs:
- Thalidomide (medication that was used to treat nausea in pregnant women in the 1950's before it got banned) causes limb deformities.
- Alcohol is associated with fetal alcohol spectrum disorders (FASD).
- Retinoic acid (Vitamin A derivatives) can lead to craniofacial and heart defects.
- Certain antibiotics (e.g., tetracyclines) affect bone and teeth development.
- Recreational substances:
- Cocaine increases the risk of miscarriage, growth restriction, and preterm birth.
- Tobacco is associated with low birth weight, prematurity, and placental problems.
- Environmental chemicals:
- Pesticides and herbicides are linked to neural and growth abnormalities.
- Heavy metals (e.g., lead, mercury) cause neurodevelopmental impairments.
- Endocrine disruptors (e.g., bisphenol A, phthalates) affect hormonal signalling and reproductive development.