ABSTRACT
Fetal bone mineralization Beginning around the middle of the second trimester, the fetus requires about 200 to 300 mg of calcium every day to mineralize its bones. This might not seem like a lot for an adult woman to provide her fetus, but it is! Young adults are generally in calcium balance. That means that they are neither gaining nor losing calcium from their skeleton. Typically, that means that a young adult nonpregnant woman who has 1000 mg of calcium in her daily diet will absorb about 30% of that (300 mg), and that she will be losing that amount in her urine or from other sites, in sweat, for example, so that, overall, she is neither gaining nor losing any calcium from her body.
