Women with immune thrombocytopenia (ITP) do not have increased risk of severe bleeding during pregnancy, and neonatal ITP (NITP) is associated with NITP history and the severity of maternal ITP during pregnancy, according to a study published in Blood.
Researchers conducted a prospective, multicenter, observational cohort study to evaluate the risk of ITP worsening during pregnancy among women with a pregestational diagnosis of ITP.
The primary outcome was the first occurrence of ITP worsening, a composite end point that included bleeding events and/or severe thrombocytopenia (<30 × 109/L) or ITP treatment modification. The researchers also evaluated the recurrence of ITP worsening as well as the incidence of NITP and identified associated risk factors.
The study included a total of 348 women with ITP who were pregnant (n=180) or not pregnant (n=168). Of those, the investigators matched women by history of splenectomy, ITP status (no response, response, or complete response), and duration, yielding a group of 131 women with pregnancy (median age, 30.4 years) and a group of 131 women without pregnancy (median age, 31.4 years). They followed the groups for 15±3 months.
The team found the first occurrence of ITP worsening was not significantly different between women with ITP with or without pregnancy (53.4 vs 37.1 per 100 person-years; hazard ratio [HR], 1.35; 95% CI, 0.89-2.03; P=.16).
They observed women with pregnancy were more likely than those without pregnancy to have recurrence of severe thrombocytopenia (HR, 2.71; 95% CI, 1.41-5.23; P =.003) and treatment modification (HR, 2.01; 95% CI, 1.14-3.57; P =.017), but not recurrence of severe bleeding events (HR, 1.38; 95% CI, 0.6-2.9; P =.4).
The researchers found 14% of neonates showed NITP with a platelet count of <50 × 109/L. Using multivariable analysis, they discovered NITP was associated with maternal history of a previous offspring with NITP (adjusted odds ratio [aOR], 5.55; 95% CI, 1.72-17.89; P =.004) and maternal platelet count of <50 × 109/L within 3 months before delivery (aOR, 4.07; 95% CI, 1.41-11.73; P =.009).
“Our study demonstrates that the severity of ITP during pregnancy should now also be considered a risk factor. Nevertheless, women with ITP should not be discouraged if they want to become pregnant, because the prognosis for the newborn is reassuring when therapeutic measures proposed in international guidelines are observed,” concluded the researchers.
Limitations of the study included potential lack of power due to enrollment of fewer women than originally planned, use of a composite endpoint, absence of systematic testing for anti-platelet antibodies in the women with pregnancy/inability to study the
possible association between the presence of anti-platelet antibodies and risk of NITP, absence of testing antiplatelet alloantibodies in thrombocytopenic neonates, and absence of testing parental platelet phenotypes.
Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Guillet S, Loustau V, Boutin E, et al. Immune thrombocytopenia and pregnancy: an exposed/nonexposed cohort study. Blood. 2023;141(1):11-21. doi:10.1182/blood.2022017277