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
Which of the following drug crosses placenta 
Select and explain. 
A. Heparin, B. Warfarin, C. Dicumarol, D. Nicoumalone
B: Warfarin
Answer: B: Warfarin 
Explanation: (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.