Prophylactic Unfractionated Heparin in Antepartum Hospitalizations: A Randomized Controlled Trial

After a thorough analysis of Dr. Mok and colleagues’ study in the July 2024 issue, we are encouraged by its conclusions, which indicate that, during extended prenatal hospital stays, unfractionated heparin (UFH) dosages adjusted based on gestational age are associated with a significantly higher rate of increased activated partial thromboplastin time compared with standard UFH dosages. This suggests that close monitoring of coagulation parameters is necessary when administering higher UFH dosages for thrombosis prophylaxis in late pregnancy.1 However, we believe there are key issues within the study that could affect the accuracy and interpretation of the results. Firstly, the study did not detail the recording of critical variables such as preeclampsia or eclampsia, postpartum hemorrhage, or HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome; history of renal disease or creatinine levels; stillbirth; or ovarian hyperstimulation syndrome (OHSS). Severe preeclampsia, eclampsia, and postpartum hemorrhage are known to significantly increase the risk of venous thromboembolism (VTE),2,3 and HELLP syndrome is closely associated with coagulopathy. The lack of recording renal disease history or creatinine levels may limit the study's understanding of UFH pharmacodynamics and dosage adjustment needs. Additionally, stillbirth is considered a strong predictor of VTE during pregnancy,4 and OHSS increases the risk of VTE by up to 100 times in patients undergoing in vitro fertilization due to the potential for ovarian enlargement, fluid shift to the third space, hemoconcentration, hypovolemia, renal failure, serous effusions, and hypercoagulability.2 The recording of these variables is therefore crucial for the study's results. Secondly, the study did not specifically consider other drugs that could affect activated partial thromboplastin time, such as antihistamines, ascorbic acid (vitamin C), chlorpromazine, and salicylates, which have been considered significant in previous studies for their potential effects on the assessment of UFH dosages.5 Overlooking these medications could significantly affect the accurate assessment of the effects of UFH dosages, thereby affecting the reliability of the study's conclusions. Therefore, although Dr. Mok and colleagues’ research provides valuable insights, addressing the aforementioned issues is essential to enhancing the scientific validity and credibility of these conclusions.