Predictors of platelet count response following intravenous immunoglobulin use for maternal thrombocytopenia

BACKGROUND: Thrombocytopenia in pregnancy may require administering intravenous immunoglobulin (IVIG), particularly when immune thrombocytopenia is suspected. However, the effectiveness of IVIG is not well-defined, creating a gap in optimal treatment strategies. This study aims to evaluate the efficacy of IVIG and identify predictors of platelet response in pregnant persons with moderate-to-severe thrombocytopenia, aiming to optimize clinical decisions and resource use. METHODS: We conducted a single-center retrospective cohort study of 79 pregnant persons with moderate-to-severe thrombocytopenia (platelets [PLT] <100 ×10⁹/L) who received IVIG between 2007 and 2020. Data on maternal demographics, PLT counts, immature platelet fraction (IPF), and IVIG administration were collected. Logistic regression identified predictors of achieving a PLT ≥ 80 × 10⁹/L and an increment ≥ 20 × 10⁹/L following IVIG administration. RESULTS: The median incremental PLT response following IVIG administration was 16 × 10⁹/L, with 49.4 % achieving PLT ≥ 80 × 10⁹/L and 46.8 % achieving an increment ≥ 20 × 10⁹/L. Predictors of a favorable response included nadir PLT < 30 × 10⁹/L (OR = 6.29), IPF < 16 % (OR = 4.85), and pre-IVIG PLT < 50 × 10⁹/L (OR = 8.67). Higher pre-IVIG PLT counts (70-100 ×10⁹/L) were associated with lower odds of achieving a significant PLT increment. DISCUSSION: IVIG effectively increases PLT counts in pregnant persons with severe thrombocytopenia, especially in those with a nadir PLT < 30 × 10⁹/L, IPF < 16 %, or pre-IVIG PLT < 50 × 10⁹/L. This study highlights the importance of careful patient selection for IVIG to enhance outcomes and conserve resources. Future research should focus on prospective studies to refine treatment guidelines and resource stewardship of IVIG for maternal thrombocytopenia.