**9. Conclusion**

The existing evidence reveals the importance of adequate vitamin D status during pregnancy for the mother, fetus, and child, although more studies are needed to clarify the exact mechanisms. In a situation where optimal vitamin D status cannot be achieved through diet and sun exposure, food fortification and supplementation seem to be proper approaches. Policies for vitamin D fortification vary across the globe, while more countries are recognizing the importance of vitamin D. The current evidence indicates the need for vitamin D supplementation in pregnant women in a situation that fortification alone cannot address the needs [262]. To our knowledge, only a few countries have free supplementation policies during pregnancy and early life. Effective systematic approaches by relevant agencies and governments are required to synthesize evidence-based recommendations for vitamin D supplementation during pregnancy and customize interventions considering cultural factors to ensure the optimal vitamin D status for pregnant women and their newborns.
