Heparin is the anticoagulant of choice during pregnancy. However, in cases of intolerance or adverse effects, another anti-coagulant agent should be administered. Here, we describe a case of hypersensitivity skin reaction seen in a 37-year-old pregnant patient at 11 weeks of gestation who used low-molecular-weight heparin (LMWH). Fondaparinux was used as an alternative during her pregnancy with a successful outcome.