Supplementary Material for: Neonatal Thymic Hemorrhage Secondary to Vitamin K Deficiency: A Case Report

Abstract
Introduction
Vitamin K deficiency bleeding (VKDB) in newborns remains a preventable yet potentially devastating condition. Maternal malabsorption disorders such as Crohn’s disease may place infants at increased risk of coagulopathy due to impaired transplacental vitamin K transfer. This report describes a rare and severe case of VKDB in a preterm infant and his postpartum mother, highlighting the potential consequences of undiagnosed maternal vitamin K deficiency and emphasizing the importance of heightened awareness in high-risk pregnancies.
Case Report
A 32-year-old woman with Crohn’s disease presented at 34+6 weeks’ gestation with preeclampsia and was delivered via urgent cesarean at 35+3 due to non-reassuring fetal testing. Her newborn son required resuscitation and developed severe coagulopathy with bruising, bleeding, and a large anterior mediastinal mass, later confirmed as hemorrhagic thymic tissue without neoplasm. Laboratory evaluation revealed markedly elevated INR and PIVKA-II, which improved with vitamin K and plasma transfusions. The mother experienced significant postpartum hemorrhage with a pelvic hematoma and coagulopathy, requiring transfusions, embolization, and vitamin K supplementation. Both mother and infant recovered following appropriate interventions. At 13 months, the infant had mild left-hand weakness but normal neurodevelopmental scores.
Conclusion
This case highlights a rare but serious complication of maternal vitamin K deficiency resulting in neonatal coagulopathy and thymic hemorrhage. Given the increased risk in mothers with malabsorptive disorders such as Crohn’s disease, screening and supplementation protocols should be considered. Further studies are needed to guide optimal management of at-risk pregnancies to prevent VKDB in both mother and newborn.