Sufficient vitamin D concentrations are needed during pregnancy to address the increasing demand for calcium, by the fetus, during its growth and development (3, 4). Pregnant women who did not receive vitamin D supplementation showed a reduction in circulating 25(OH)D levels during the third trimester compared with the first trimester (4, 5). Several observational studies have reported that low maternal circulating 25(OH)D concentrations in pregnant women may have negative health consequences for both mothers and newborns (3, 6). Studies have suggested that lower levels of circulating 25(OH)D are associated with risks of recurrent pregnancy losses, preeclampsia, gestational diabetes, maternal infections, preterm birth, small-for-gestational-age (SGA) infants, and poor offspring health