Abstract
BACKGROUND: Thrombocytopenia in preterm infants born to mothers with systemic lupus erythematosus (SLE) is poorly characterized, despite its potential link to adverse outcomes. Our understanding of platelet dynamics, risk factors, and clinical outcomes in this population is limited, necessitating further investigation. PURPOSE: This study aimed to characterize the incidence, timing, and severity of thrombocytopenia in this population; to identify associated maternal and neonatal risk factors; and to evaluate its association with adverse outcomes. METHODS: We included 154 preterm infants born to mothers with SLE who were admitted to Shanghai Children's Medical Center within 24 hours of birth between 2014 and 2024. Logistic regression was used to identify risk factors and outcomes associated with neonatal thrombocytopenia. RESULTS: Thrombocytopenia (platelet count < 150 ×109/L) occurred in 32.5% of infants, and severe form (< 50 ×109/L) occurred in 4.6%. The condition peaked on postnatal days 4-5, and 16% of affected infants required intervention. Late preterm infants (adjusted odds ratio [aOR], 0.15; 95% confidence interval [CI], 0.05-0.42), moderate preterm infants (aOR, 0.26; 95% CI, 0.09-0.76), and maternal hydroxychloroquine use (aOR, 0.19; 95% CI, 0.07-0.52) were protective factors. In contrast, maternal hypertensive disorders of pregnancy (HDP; aOR, 3.41; 95% CI, 1.06-10.93) increased the risk. Infants with thrombocytopenia had significantly higher risks of intracranial hemorrhage (aOR, 4.27; 95% CI, 1.65-11.00) and late-onset sepsis (aOR, 11.00; 95% CI, 1.23-98.14). CONCLUSION: Preterm infants exposed to maternal SLE frequently developed thrombocytopenia, but most cases were self-limited. Key risk modulators included gestational age, maternal HDP, and hydroxychloroquine use. Furthermore, thrombocytopenia was significantly associated with neonatal morbidity.