Recombinant Human Thrombopoietin Therapy for Primary Immune Thrombocytopenia in Pregnancy: a Retrospective Comparative Cohort Study

Background: Treatment options for pregnant women with immune thrombocytopenia (ITP) who do not respond to first-line treatment are limited. Few studies have reported the use of recombinant human thrombopoietin (rhTPO) for this subset of patients.

Aims: To investigate the efficacy and safety of rhTPO in ITP during pregnancy and determine obstetric outcomes and predictors of treatment response.

Methods: From July 2013 to October 2022, the data of 81 pregnant women with ITP and a platelet count < 30 × 10/L who did not respond to steroids and/or intravenous immunoglobulin were retrospectively analysed. Of these patients, 33 received rhTPO treatment (rhTPO group) while 48 did not (control group). Baseline characteristics, haematological disease outcomes before delivery, obstetric outcomes, and adverse events were compared between groups. In the rhTPO group, a generalised estimating equation (GEE) was used to investigate the factors influencing the response to rhTPO treatment.

Results: The baseline characteristics were comparable between both groups (P > 0.05, both). Compared with controls, rhTPO patients had higher platelet counts (median [interquartile range]: 42 [21.5-67.5] vs. 25 [19-29] × 10/L, P = 0.002), lower bleeding rate (6.1% vs. 25%, P = 0.027), and lower platelet transfusion rate before delivery (57.6% vs. 97.9%, P < 0.001). Gestational weeks of delivery (37.6 [37-38.4] vs 37.1 [37-37.2] weeks, P = 0.001) were longer in the rhTPO group than in the control group. The rates of caesarean section, postpartum haemorrhage, foetal or neonatal complications, and complication types in both groups were similar (all P > 0.05). No liver or renal function impairment or thrombosis cases were observed in the rhTPO group. GEE analysis revealed that the baseline mean platelet volume (MPV) (odds ratio [OR]: 0.522, P = 0.002) and platelet-to-lymphocyte ratio (PLR) (OR: 1.214, P = 0.025) were predictors of response to rhTPO treatment.

Conclusion: rhTPO may be an effective and safe treatment option for pregnancies with ITP that do not respond to first-line treatment; it may have slightly prolonged the gestational age of delivery. Patients with a low baseline MPV and high baseline PLR may be more responsive to rhTPO treatment. The present study serves as a foundation for future research.