Abstract
Vitamin D insufficiency is prevalent among pregnant women and infants worldwide. Expectant mothers with a heightened risk of vitamin D deficiency may have notably low levels of 25-hydroxyvitamin D (25(OH)D) in their newborns, raising the likelihood of nutritional rickets. Numerous observational studies suggest a link between inadequate vitamin D levels during pregnancy and various adverse perinatal outcomes such as hypertensive disorders (like preeclampsia), restricted fetal growth, and premature birth. Nevertheless, the limited number of large-scale randomized controlled trials (RCTs) conducted so far have produced conflicting findings regarding the effectiveness of vitamin D supplementation in enhancing perinatal outcomes.