There are no sufficient and well-organized studies on the use of heparin by pregnant women. In available reports, exposure of heparin to pregnant women did not reveal any proof of an augmented risk of hostile fetal or maternal results in humans. With regard to studies carried out on humans as well as animals, it has been revealed that heparin sodium does not penetrate the placenta membrane (Miyashita, Hayashi & Kuro, 2000). Heparin administration to expectant animals at higher doses than the maximum daily dose for humans, with regard to body weight, leads to improved resorptions. Heparin sodium ought to be utilized during pregnancy only when the potential advantage validates the probable danger to the fetus.