Calcium blocks the absorption of iron, a mineral important for all pregnant women and their babies. Obtaining a sufficient amount of iron during pregnancy is essential to the health of both you and your developing baby. Also, prenatals that include calcium have less than 20% of the recommended daily amount needed during pregnancy, so 80% or more of the calcium requirement must be obtained from other sources. Learn more here more about calcium benefits to pregnancy, foods that are a good source of calcium and more detail of why there is no calcium in TriCare Prenatal™ DHA ONE® with Folate.