Is calcium safe during pregnancy?

What does the evidence say about calcium during pregnancy?

1. 1,000 mg a day is the recommended dietary allowance for pregnancy at ages 19 to 50, and 1,300 mg at ages 14 to 18. Unlike most nutrients, calcium needs do not increase during pregnancy. 1
2. The tolerable upper intake level in pregnancy is 2,500 mg a day at ages 19 to 50 and 3,000 mg at ages 14 to 18, covering total intake from all sources. 1
3. Calcium supplementation may reduce the risk of preeclampsia, with the clearest signal in people whose baseline calcium intake is low. 1
4. Supplemental calcium, as opposed to calcium from food, has been associated with a higher risk of kidney stones, which is one reason the guidance favors food first. 1
5. About 21.2 percent of pregnant women in the United States fall below the estimated average requirement for calcium from food, and most prenatal supplements carry only a median of 200 mg per serving, far short of the daily target. 2

Is calcium safe in each trimester?

• First trimester. The target is the same all pregnancy, and it is the one number that does not rise when you conceive. If dairy is off the table because of aversions, fortified plant milks and canned fish with soft bones close the gap without a supplement.
• Second trimester. Fetal skeletal growth picks up now, drawing more calcium across the placenta. Your body adapts by absorbing more of what you eat, so meeting the same target still works.
• Third trimester. Bone mineralization is at its heaviest in the third trimester. Calcium also competes with iron for absorption, so if you take both as separate supplements it is worth spacing them apart in the day.