How do scientists identify teragogens? Scientists conduct animal
studies or rely on observation to determine if a substance is a
teratogen. - Animal studies - Animal studies are the primary way
a medication is determined to be safe for humans. It's important
to keep in mind, however, that a drug does not always affect an
animal the same way it will affect a human. - Observations from
human exposure - In the past, there have been medications that
caused birth defects. One example is thalidomide, which was
removed from the market in the 1960s when it was found to cause
babies to be born with missing and malformed limbs to mothers
who took the drug early in pregnancy. How are medications rated
for their safety? Before 1980, most medications included
literature that stated that their use in pregnancy had not been
approved. Since that time, the US Food and Drug Administration
(FDA) has created five drug categories to designate the safety
of medications for their use during pregnancy, with A being the
safest and X