Are calcium-carbonate antacids safe during pregnancy?

What does the evidence say about calcium-carbonate antacids during pregnancy?

1. Calcium-carbonate antacids taken at normal over-the-counter doses have not been linked to a higher risk of birth defects. 1
2. Getting more than 2,500 to 3,000 mg of calcium a day during pregnancy can strain your kidneys and, over time, lead to a condition called milk-alkali syndrome. 2
3. This safety summary is specifically about plain calcium carbonate: antacids with aluminum, magnesium trisilicate, or bismuth have a different pregnancy profile. 1
4. Try smaller meals and staying upright after eating first, then a calcium-carbonate antacid, with an H2 blocker as a next step if you still need more relief. 3

Is calcium-carbonate antacids safe in each trimester?

• First trimester. Using antacids now and then for reflux is fine. Just remember your prenatal vitamin already has some calcium in it, so keep an eye on your total.
• Second trimester. Same as the first trimester. Reflux often gets worse now as your growing belly and hormones add more pressure.
• Third trimester. Reflux usually peaks in the third trimester. If you're reaching for antacids every day, talk with your provider, since adding an H2 blocker might work better for you.