Risk of thrombocytopenia in neonates of thrombocytopenic mothers

Maternal thrombocytopenia during pregnancy may occur due to several possible etiologies, with potential neonatal impact. The aim of the present study was to investigate whether there is a correlation between maternal and neonatal platelet count among women with thrombocytopenia during pregnancy.

A cross-sectional retrospective study (2012-2019) was conducted at a tertiary medical center. Complete blood count was routinely measured in all patients on admission to the delivery ward. Thrombocytopenia was defined as a platelet count below 150 K/μL. Clinical and outcome parameters of thrombocytopenic mothers and their newborns were collected from the electronic files and analyzed by severity of maternal thrombocytopenia.

Of 45 385 women with a documented platelet count at admission, 2841 (6.24%) had thrombocytopenia: 2623 (5.7%) mild (100-149 K/μL), 207 (0.45%) moderate (50-99 K/μL), and 11 (0.02%) severe (<50 K/μL). Eight newborns had thrombocytopenia; corresponding rates by severity of maternal thrombocytopenia were 0.11%, 1.43%, and 18.18% (P = 0.04). None of the thrombocytopenic neonates had an intraventricular hemorrhage or other bleeding complications. The correlation between maternal and neonatal platelet counts was weak (Pearson r = 0.038; P = 0.046).

We suggest that although the chances of neonatal thrombocytopenia are higher with worsening maternal thrombocytopenia, actual occurrence is rare, and the correlation is poor. Therefore, maternal thrombocytopenia cannot be regarded as a significant risk factor for neonatal thrombocytopenia. Neonatal platelet count should be obtained when maternal thrombocytopenia is autoimmune or less than 100 K/μL.