Final answer:
Warfarin is the drug in question; it is a teratogen that can negatively impact fetal development and even lead to fetal bleeding in later stages of pregnancy.
Step-by-step explanation:
The drug that is a teratogen in early pregnancy and will cause fetal bleeding in later pregnancy is Warfarin. Teratogens are environmental agents that cause harm to a developing fetus, resulting in birth defects or developmental malformations. Warfarin, used for its anticoagulant properties, is associated with risks, including mental, growth restriction, nasal hypoplasia, and ophthalmic abnormalities when taken during pregnancy. Thalidomide is another classic teratogen known to cause severe limb defects when taken by women during pregnancy.
Teratogens come in various forms, including some prescription drugs, illicit drugs like heroin, cocaine, and methamphetamine, alcohol, and even environmental exposures such as some chemicals in pesticides or plastics. The effects of a teratogen on a fetus depend on several factors, including its potency as a mutagen, the dose, and the stage of pregnancy during which exposure occurs.