Physiological impact of pregnancy on renal function; a prospective cohort study

Introduction: Pregnancy induces substantial physiological adjustments that extend to renal function, driven by changes in blood volume, hormonal activity, and metabolic demands that alter the normal behavior of key biochemical markers. Understanding how these renal parameters evolve across gestation is essential for distinguishing healthy physiological adaptation from early signs of renal impairment. Objectives: This study aimed to examine trimester‑specific changes in renal function within a prospective cohort of pregnant women to clarify the expected trajectory of renal biomarkers during normal pregnancy. Materials and Methods: The study employed a prospective cohort design conducted at a maternity teaching hospital in Nasiriyah, Iraq, enrolling 49 first‑trimester singleton pregnant women who were followed from January 2024 to January 2025 to assess longitudinal renal changes. Eligible participants were singleton pregnant women who provided informed written consent. Demographic and obstetric data were collected at enrollment, and venous blood samples were obtained at the end of each trimester to measure blood urea and serum creatinine using standardized biochemical procedures. Renal biomarkers were compared across trimesters to evaluate alterations in kidney function during pregnancy. Results: The study included 49 pregnant women with a mean age of 30.22 ± 8.25 years. The results demonstrated progressive alterations in renal biomarkers across pregnancy, with both blood urea and creatinine levels indicating a steady and statistically significant rise from the first to the third trimester (P<0.05). Conclusion: Pregnancy is associated with a steady and significant increase in renal biomarkers across trimesters. These findings highlight the importance of considering trimester‑specific changes when evaluating maternal renal function.