Question | Answer |
Embryotoxicity | When a substance given to a pregnant animal during any portion of gestation results in significant pregnancy loss, either by preventing implantation or by post-implantation death |
Fetotoxicity | When a substance given to a pregnant animal during any portion of gestation leads to offspring showing signs of delayed development compared to controls |
Maternal toxicity | When a substance given to a pregnant animal during any portion of gestation leads to deleterious effects on behavior, excretion, appearance, body weight, organ weights and/or organ function |
Intra-species variability | Within a single spcies, the teratogenic effects and frequencies may vary based on maternal and fetal genetic suspectibility, placental and hormonal factors and other maternal-fetal factors |
NOAEL | No Observable adverse effects levels, highest dose |
LOAEL | Lowest Observable adverse effects level (Equivalent to threshold dose) |
Advantages to interpreting animal studies | Easily controlled, usually provide large litters with short gestation period, provide models, occasional models for humans |
Disadvantages to interpreting animal studies | Different metabolism and physiology than humans, markest interspecies variation, dose equivalency is not always clearly calculated, animals are usually exposed to long term high doses, no one species has been found to be most predictive |