Efficacy of heparin on in-vitro fertilization outcomes: a systematic review and SWOT analysis

INTRODUCTION: Embryo implantation is a crucial step in pregnancy that requires interaction between the embryo and the endometrial lining, facilitated by cytokines, growth factors, and adhesion molecules. Failures in this process are a leading cause of implantation failure and miscarriage in in-vitro fertilization (IVF) treatments. Heparin has shown potential to improve outcomes by enhancing endometrial receptivity, promoting angiogenesis, and modulating inflammatory responses. This study aims to provide an overview of the main characteristics of existing research on the role of heparin adjuvant therapy in IVF cycles. EVIDENCE ACQUISITION: A comprehensive bibliographic search was systematically conducted from inception to 2024, focusing on studies that evaluated the impact of heparin adjuvant therapy in IVF cycles and compared clinical outcomes between case and control groups. EVIDENCE SYNTHESIS: A total of 31 studies were included. Most of the studies have focused on patients with recurrent implantation failure, defined using highly heterogeneous criteria across studies, as well as patients with both congenital and acquired thrombophilic disorders. Additionally, most of the studies involved small sample sizes. CONCLUSIONS: Current evidence does not adequately support the routine use of heparin in IVF cycles. To date, the research is plagued by methodological inconsistencies, which undermine both the reliability and the applicability of the findings.