Journal of Biology and Nature

Pregnancy is associated with progressive physiological changes in haematological and haemostatic systems that support maternal and foetal wellbeing but may also influence susceptibility to pregnancy-related complications. This study assessed trimester-specific haematological and haemostatic changes, determined the predictive value of these parameters for pregnancy-related complications, and examined correlations among selected haematological and haemostatic parameters in pregnant women attending antenatal care at State Specialist Hospital, Maiduguri, Borno State, Nigeria. A hospital-based analytical study was conducted among 79 pregnant women recruited in the second trimester (13–26 weeks) and followed into the third trimester (≥27 weeks to term). Venous blood samples were collected into EDTA and sodium citrate containers and analysed for white blood cell count, haemoglobin, haematocrit, platelet count, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, differential leukocyte counts, prothrombin time, international normalised ratio, activated partial thromboplastin time and D-dimer. Paired comparisons for trimester-specific changes were performed, and Pearson correlation and binary logistic regression were used to assess relationships and predictors. Receiver operating characteristic analysis was used to assess predictive discrimination. WBC increased significantly from 8.28 ± 2.62 ×10⁹/L in the second trimester to 10.39 ± 2.69 ×10⁹/L in the third trimester (p < 0.01). Haematocrit decreased from 30.69 ± 2.92% to 28.70 ± 7.74% (p = 0.033), while MCV and MCHC decreased significantly and MCH increased significantly. Platelet count decreased markedly from 281.1 ± 66.37 ×10⁹/L to 175.4 ± 45.35 ×10⁹/L (p < 0.01). PT, INR, APTT and D-dimer increased significantly across trimesters. In the prediction model, second-trimester HCT was negatively associated with complications (OR = 0.55, p = 0.017), whereas third-trimester HCT was positively associated (OR = 1.09, p = 0.024). Second-trimester APTT was also significant (OR = 0.95, p = 0.027), while second-trimester haemoglobin approached statistical significance (OR = 3.95, p = 0.055). The ROC model yielded an AUC of 0.780 (95% CI: 0.705–0.855; p < 0.001), indicating acceptable-to-good discrimination. Correlation analyses demonstrated significant relationships among selected leukocyte, red-cell and haemostatic parameters. The findings demonstrate important trimester-specific haematological and haemostatic adaptations and suggest that selected routine laboratory parameters may contribute to antenatal risk assessment.