The Correlation Between Vitamin D Levels and Thyroid Functions in Early Pregnancy

INTRODUCTION: Vitamin D deficiency (serum vitamin D <10 ng/ml) and thyroid dysfunctions
are prevalent issues globally, particularly during pregnancy. Evidence suggests a potential link
between thyroid function and vitamin D levels. This study aims to investigate the correlation
between serum vitamin D levels and thyroid functions in women during the first trimester of
pregnancy.

METHODS: The study was conducted retrospectively at a University Education and Research Hospital’s pregnancy clinic, covering data from August 2023 to March 2024. The sample group consisted of first-trimester pregnant women who attended routine pregnancy check-ups and had complete vitamin D levels and thyroid function tests (n = 185). The sociodemographic data form and blood serum level assessment forms were used as data collection tools. The data were analyzed using descriptive statistics and correlation analysis.
RESULTS: The average age of the pregnant women participating in our study was 27.6±4.9 years,
and the Body Mass Index (BMI) was 25.4±4.8 (overweight). The mean number of pregnancies
was 1.13±0.3, and the gestational week was 8.19±1.8. Of the participants, 35 had subclinical
hypothyroidism, 37 had thyroiditis, and 113 had normal thyroid functions. The study identified
36 women with normal/adequate vitamin D levels (≥20 ng/ml), 113 with vitamin D
insufficiency (10–20 ng/ml), and 36 with vitamin D deficiency (<10 ng/ml). The correlation
analysis revealed no significant relationship between the thyroid function tests and vitamin D
levels of the pregnant women.

DISCUSSION AND CONCLUSION: It was determined that vitamin D levels do not affect thyroid gland function in the first trimester.