Assessment of Serum Concentrations of Vitamin B12, Folic Acid, and Vitamin D in Women of Reproductive Age to Determine Recommended Supplementation Doses in the Preconception Period and During Pregnancy

Micronutrient intake-particularly vitamin B12, folic acid, and vitamin D-is essential during the preconception period and pregnancy to support fetal growth and reduce the risk of adverse outcomes such as preterm birth, low birth weight, and congenital anomalies. However, excessive intake may carry potential risks, including epigenetic changes, insulin resistance, and increased incidence of childhood asthma and obesity. Additionally, folic acid may mask underlying vitamin B12 deficiency, delaying diagnosis and increasing the risk of neurological complications.

This cross-sectional study addresses the lack of region-specific data on micronutrient status among women of reproductive age in Herzegovina. Although international guidelines provide general recommendations, they may not reflect the actual needs of this population. The study aims to evaluate the prevalence of micronutrient deficiency, adequacy, or excess to guide the development of evidence-based, locally adapted supplementation strategies.

A total of 360 women aged 18 to 49 will be enrolled between December 1, 2024, and December 1, 2025, after providing informed consent. Blood samples will be collected and centrifuged, and serum concentrations of vitamin B12, folic acid, and vitamin D will be measured using chemiluminescent microparticle immunoassays (CMIA) on the Alinity ci platform (Abbott Diagnostics). The study will be conducted in three phases: (1) participant recruitment and sample collection, (2) laboratory analysis and statistical evaluation using MedCalc software, and (3) preparation and publication of results in a peer-reviewed journal. The findings are expected to support more personalised and rational approaches to micronutrient supplementation in women planning pregnancy or who are already pregnant.