Overall, the most common specific causes of thrombocytopenia include Pregnancy (gestational thrombocytopenia; HELLP syndrome [h emolysis, e levated l iver enzymes, and l ow p latelets]) Drugs that cause immune-mediated platelet destruction (commonly, heparin, trimethoprim / sulfamethoxazole, rarely quinine [cocktail purpura] or abciximab), and rarely vaccinations (eg, influenza, shingles, measles, mumps, and rubella, A COVID-19) Drugs that cause dose-dependent bone marrow suppression (eg, chemotherapeutic agents, ethanol) Systemic infection Immune disorders (eg, immune thrombocytopenia [ITP], antiphospholipid antibody syndrome, systemic lupus erythematosus) Platelet dysfunction Platelet dysfunction may stem from an intrinsic platelet defect or from an extrinsic factor that alters the function of normal platelets.