Heparin-induced thrombocytopenia is rare in pregnancy

Objective: The indications for heparin use during pregnancy are expanding; however, heparin is associated with serious adverse effects including heparin-induced thrombocytopenia. Low-molecular-weight heparin is expensive but is associated with less frequent occurrences of heparin-induced thrombocytopenia in the nonpregnant population. However, the incidence of heparin-induced thrombocytopenia during pregnancy is unknown. The purpose of this study was to compare the incidence of heparin-induced thrombocytopenia in pregnant and nonpregnant women. Study Design: This is a retrospective cohort comparison. Pregnant and nonpregnant women were identified by means of diagnosis related group and Current Procedural Terminology code searches at three medical centers in Utah; the incidence of heparin-induced thrombocytopenia in the two groups was compared. Results: There were 10 (4%) cases of thrombocytopenia among 244 heparin-treated pregnant patients and 26 (11%) cases among the 244 nonpregnant controls. There were no cases of heparin-induced thrombocytopenia in the pregnant group, but there were 10 (4%) cases in the control group (P = .0014). Conclusion: Heparin-induced thrombocytopenia is extremely rare in pregnant women. (Am J Obstet Gynecol 2001;185:148-52.)