The importance of vitamin D supplementation during pregnancy is easily overlooked. Many people think that they can get enough vitamin D from the sun; however, they often neglect the factors influencing vitamin D via sun exposure. According to the analysis of the national nutrition and health data of the Ministry of Health and Welfare by professor Mei-Xuan Li from the School of Public Health, National Defense Medical Center, up to 98% of people have insufficient vitamin D concentration in the blood (the standard is 33ug/mL).