This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematology, Subject name: Pharmacology
[{'content': 'Which of the following drug crosses placenta \nSelect and explain. \nA. Heparin, B. Warfarin, C. Dicumarol, D. Nicoumalone', 'role': 'user'}, {'content': 'Answer: B \nExplanation: (Warfarin) (601-KDT6th)* WARFARIN - It crosses placenta and is secreted in milk however quantity of active form is generally insufficient to affect the suckling infants* HEPARIN - does not cross BBB or placenta**- It is the anticoagulant of choice during pregnancy*** Bleeding due to overdose is the most serious complication of heparin therapy** other side effects are thrombocytopenia, * alopecia, * osteoporosis*, hypersensitivity reactions.', 'role': 'assistant'}]