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
The anticoagulant of choice in pregnancy is: 
Select and explain. 
A. Heparin, B. Warfarin, C. Dicumarol, D. Phenindione
A: Heparin
Answer: A: Heparin 
Explanation: Heparin because of its large molecular size, heparin does not cross placental barrier therefore can be used in pregnancy. From medical pharmacology padmaja 4th edition Page no 335