Principles of teratology : lecture notes of embryology

Principles of Teratology: ( capacity of an agent to produce birth defects)

1. Susceptibility to teratogenesis depends on the genotype of the conceptus
2. Susceptibility to teratogens varies with the developmental stage at the time of exposure
3. Manifestations of abnormal development  depend on dose and duration of exposure to a teratogen
4. Teratogens act in specific ways on developing cells to initiate abnormal embryogenesis
5. Manifestations of abnormal development are death, malformation, growth retardation & functional disorders