ABSTRACT
INTRODUCTION: The purpose of the research was to explore the relationship between pathology and pregnancy outcomes with serum 25-hydroxycholecalciferol levels and vitamin D supplementation. METHODS: A literature search was performed for systematic literature reviews published between January 2018 and February 2023. Forty-two publications were selected for further analysis. RESULTS: This study demonstrates that elevated maternal serum 25(OH)D levels are associated with a decreased risk of preterm labour and various pregnancy-related health issues, highlighting the protective benefits of adequate vitamin D during pregnancy. CONCLUSION: Vitamin D supplementation during pregnancy at a dose of 2,000 IU or higher is preventive for pre-eclampsia, insulin resistance, and the development of bronchial asthma in early childhood. Vitamin D screening is indicated for all pregnant women. Dosages of vitamin D preparations should be determined individually, considering laboratory tests and risk factors.