Publication:

Trimester specific changes in nutritional and iron related biomarkers among pregnant women in Calabar, Nigeria: a longitudinal study

Background Nutritional deficiencies are common in pregnant women in developing countries and contribute to poor pregnancy outcomes. This longitudinal study assessed trimester‑specific trends in nutritional and iron‑related biomarkers in Calabar, Nigeria.

Methods Seventy‑two pregnant women (18-41 years) were enrolled in the first trimester and followed to the third trimester at the University of Calabar Teaching Hospital. Fifty age‑ and parity‑matched non‑pregnant women served as controls. Blood samples were collected at 10, 24 and 36 weeks of gestation. Total protein, albumin, iron, unsaturated iron‑binding capacity (UIBC), ferritin, folate, vitamin B12 and soluble transferrin receptors (sTfR) were analysed; total iron‑binding capacity (TIBC) and transferrin saturation (TS) were calculated.

Results Albumin, folate and vitamin B12 were significantly lower in pregnant women by the second trimester compared to non‑pregnant controls. Within the pregnant cohort, albumin (39.6±7.7 to 24.3±2.7 g/L, p=0.001), ferritin (65.7±54.8 to 30.3±20.4 ng/mL, p=0.01) and total protein (74.4±12.4 to 60.5±4.1 g/L, p=0.01) declined progressively. Folate dipped in the second trimester (14.8±8.2 ng/mL) before rising in the third. Serum iron and TS% increased significantly in the third trimester. Over 90% of participants had abnormal total protein or albumin levels by the third trimester.

Conclusions Key nutritional biomarkers decline significantly in the second and third trimesters, supporting enhanced targeted nutritional monitoring and interventions in later pregnancy.