Prothrombotic Genetic Mutations Are Associated with Sub-Clinical Placental Vascular Lesions: A Histopathological and...

Inherited thrombophilia is increasingly recognized as a contributing factor to placental vascular pathology and adverse pregnancy outcomes. While the clinical implications are well-established, fewer studies have systematically explored the histopathological changes associated with specific genetic mutations in thrombophilic pregnancies.

This retrospective observational study included two cohorts of placental samples collected between September 2020 and September 2024 at a tertiary maternity hospital. Group 1 included women diagnosed with hereditary thrombophilia, and Group 2 served as controls without known maternal pathology. Placentas were examined macroscopically and histologically, with pathologists blinded to group allocation. Histological lesions were classified according to the Amsterdam Consensus and quantified using a composite score (0-5) based on five key vascular features.

Placental lesions associated with maternal vascular malperfusion-including infarctions, intervillous thrombosis, stromal fibrosis, villous stasis, and acute atherosis-were significantly more frequent in the thrombophilia group (p < 0.05 for most lesions). A combination of well-established thrombophilic mutations (Factor V Leiden, Prothrombin G20210A) and other genetic polymorphisms with uncertain clinical relevance (MTHFR C677T, PAI-1 4G/4G) showed moderate-to-strong correlations with histopathological markers of placental vascular injury. A composite histological score ≥3 was significantly associated with thrombophilia (p < 0.001). Umbilical cord abnormalities, particularly altered coiling and hypertwisting, were also more prevalent in thrombophilic cases.

Thrombophilia is associated with distinct and quantifiable placental vascular lesions, even in pregnancies without overt clinical complications. The use of a histological scoring system may aid in the retrospective identification of thrombophilia-related placental pathology and support the integration of genetic and histologic data in perinatal risk assessment.