A Predictive Model for Treatment Effectiveness in Severe Primary Immune Thrombocytopenia during Pregnancy: A Retrospective Study in a Tertiary Critical Maternity Referral Center.

Objectives: The study aimed to identify factors influencing the severity of primary immune thrombocytopenia (ITP) during pregnancy, develop a predictive model for treatment response, and report maternal and neonatal outcomes associated with severe ITP.

Design: A retrospective analysis was conducted on 155 pregnancies with severe ITP between January 2018 and April 2023 at a tertiary critical maternity referral center in Shanghai, China. Participants/Materials: The study included 155 pregnancies diagnosed with severe ITP, divided into groups based on the lowest platelet count (<30 × 109/L vs. 30-50 × 109/L) and first-line treatment response (non-response vs. response).

Setting: The study was conducted at Renji Hospital, Shanghai Jiao Tong University School of Medicine, a tertiary critical maternity rescue referral center.

Methods: Clinical characteristics and outcomes were compared between groups. A multivariable logistic regression model was used to identify factors associated with the severity of ITP. A prediction model for treatment response was established using LASSO-logistic regression and internally validated.

Results: ITP severity was found to be correlated with low maximum amplitude of thromboelastography (OR 5.43, 95% CI: 1.48-16.00, p = 0.002), bleeding events (OR 4.91, 95% CI: 1.62-14.86, p = 0.005), and low reticulocytes (OR 2.40 × 10-7, 95% CI: 1.06 × 10-13 to 0.55, p = 0.04). Of the 118 patients who received first-line therapy, 52 (44%) responded. The dataset was randomly split into a training (N = 99) and test (N = 23) set with a ratio of 8:2. A predictive nomogram was created and internally validated showing good discrimination. The model yielded an area under receiver operating characteristic curve of 0.78 (0.69-0.87) and 0.85 (0.67-1.00) in the training and validation cohort, respectively. Earlier delivery and high rate of neonatal intensive care unit admission occurred with severe ITP and treatment failure.

Limitations: The study was limited by a relatively small sample size and the retrospective observational design, which imposed limitations on the assessment of treatment efficacy.

Conclusions: We identified clinical predictors of ITP severity and treatment resistance during pregnancy. A nomogram predicting first-line response was validated. These findings can facilitate clinical decision-making and counseling regarding this challenging pregnancy complication.