Causes and relative incidence of thrombocytopenia in pregnancy
| Pregnancy-specific |
| Isolated thrombocytopenia |
| Gestational thrombocytopenia (70%-80%) |
| Thrombocytopenia associated with systemic disorders |
| Preeclampsia (15%-20%) |
| HELLP syndrome (< 1%) |
| Acute fatty liver of pregnancy (< 1%) |
| Not pregnancy-specific |
| Isolated thrombocytopenia |
| Primary immune thrombocytopenia–ITP (1%-4%) |
| Secondary ITP (< 1%)* |
| Drug-induced thrombocytopenia (< 1%) |
| Type IIb VWD (< 1%) |
| Congenital (< 1%) |
| Thrombocytopenia associated with systemic disorders |
| TTP/HUS (< 1%) |
| SLE (< 1%) |
| Antiphospholipid antibody syndrome (< 1%) |
| Viral infections (< 1%) |
| Bone marrow disorders (< 1%) |
| Nutritional deficiency (< 1%) |
| Splenic sequestration (liver diseases, portal vein thrombosis, storage disease, etc; < 1%) |
| Pregnancy-specific |
| Isolated thrombocytopenia |
| Gestational thrombocytopenia (70%-80%) |
| Thrombocytopenia associated with systemic disorders |
| Preeclampsia (15%-20%) |
| HELLP syndrome (< 1%) |
| Acute fatty liver of pregnancy (< 1%) |
| Not pregnancy-specific |
| Isolated thrombocytopenia |
| Primary immune thrombocytopenia–ITP (1%-4%) |
| Secondary ITP (< 1%)* |
| Drug-induced thrombocytopenia (< 1%) |
| Type IIb VWD (< 1%) |
| Congenital (< 1%) |
| Thrombocytopenia associated with systemic disorders |
| TTP/HUS (< 1%) |
| SLE (< 1%) |
| Antiphospholipid antibody syndrome (< 1%) |
| Viral infections (< 1%) |
| Bone marrow disorders (< 1%) |
| Nutritional deficiency (< 1%) |
| Splenic sequestration (liver diseases, portal vein thrombosis, storage disease, etc; < 1%) |
Secondary ITP includes isolated thrombocytopenia secondary to some infections (HIV, HCV, H pylori) and to other autoimmune disorders, such as SLE.