Mimicry in Maternal Medicine: Distinguishing Thrombotic Thrombocytopenic Purpura from HELLP Superimposed on Immune Thrombocytopenia

Background: Severe thrombocytopenia in late pregnancy poses significant diagnostic dilemmas, particularly when features of immune thrombocytopenia purpura (ITP), HELLP syndrome, and thrombotic thrombocytopenic purpura (TTP) converge.In such cases, obstetricians must maintain a high index of suspicion for overlapping hematological disorders and preeclampsia mimickers-especially when patient fails to improve after delivery but responds to immunomodulatory therapies.Case presentation: A 32-year-old gravida 4, para 3 woman presented at 37 + 5 weeks with profound thrombocytopenia (15,000/μL) and a history of unexplained neonatal deaths following prior full-term vaginal deliveries.Despite prior transfusions and documentation of a "bleeding defect, " she had never undergone formal hematologic evaluation.A PLASMIC score of seven suggested high-risk for TTP.However, her clinical course revealed HELLP syndrome superimposed on undiagnosed chronic ITP.She responded dramatically to intravenous immunoglobulin (IVIG) followed by corticosteroids, and recovered without plasma exchange (PLEX).Conclusions: This case underscores the limitations of diagnostic scoring systems like the PLASMIC score in pregnancy and highlights the importance of a trajectory-based, multidisciplinary approach.Missed ITP diagnosis across multiple pregnancies resulted in high maternal and perinatal morbidity-emphasizing the need for systematic hematologic evaluation in antenatal care.