Haematological and Haemostatic Alterations in Women Using Hormonal Contraceptives at a Reproductive Health Clinic in Calabar, Cross River State

Hormonal contraceptives influence multiple physiological pathways including haematopoiesis and coagulation, and their safety profiles require evaluation within specific population contexts. This study assessed haematological and haemostatic alterations associated with hormonal contraceptive use among women attending a reproductive health clinic in Calabar, Cross River State, South South Nigeria. A cross-sectional comparative design recruited 120 women comprising four groups: combined oral contraceptive users, progestin-only pill users, injectable contraceptive users, and non-contraceptive-using controls. Full blood count, prothrombin time, activated partial thromboplastin time, fibrinogen, and D-dimer were measured using standard laboratory methods. Duration of contraceptive use, smoking status, and family history of thrombosis were documented. ANOVA and logistic regression were applied. Results showed that combined oral contraceptive users had significantly elevated fibrinogen and D-dimer concentrations, with shortened prothrombin time compared to controls, indicating a prothrombotic tendency. Haemoglobin levels were mildly reduced in injectable contraceptive users. Progestin-only users showed intermediate haemostatic profiles. Duration of use was positively correlated with prothrombotic marker concentrations. This study provides empirical data supporting contraceptive-specific haemostatic monitoring, a gap in routine reproductive health practice in Nigeria. Pre-prescription coagulation screening and periodic haematological assessment are recommended, particularly for combined hormonal contraceptive users. Keywords: hormonal contraceptives, haemostasis, coagulation, D-dimer, Calabar.