5. Conclusions
In conclusion, 800 IU/day of vitamin D3 supplementation effectively increased the 25OHD levels and improved the vitamin D sufficiency status in pregnant women with OW/OB in pregnancy. However, we found no effect on lipid profiles or pregnancy outcomes. Larger trials with varying higher vitamin D3 supplement doses and increased sample sizes are warranted to examine the impact on maternal and birth outcomes in this population. In subsequent studies, it would also be valuable to delve deeper into the effects of vitamin D3 supplementation on long-term maternal and foetal outcomes beyond delivery timepoint.