Antacids in Pregnancy: Safe Options and What to Avoid

When you're pregnant, heartburn isn't just annoying—it can feel relentless. Antacids in pregnancy, over-the-counter medications that neutralize stomach acid to relieve heartburn and indigestion. Also known as acid reflux remedies, they’re one of the most common go-to solutions for expectant mothers dealing with daily discomfort. But not all antacids are created equal. Some contain ingredients that could affect your baby or interfere with nutrient absorption. Knowing which ones are safe—and which to skip—can make a real difference in how you feel day to day.

Heartburn during pregnancy happens because hormones relax the valve between your stomach and esophagus, and your growing uterus pushes upward. This isn’t just a third-trimester problem—many women start feeling it as early as the first trimester. The good news? You don’t have to suffer. Calcium carbonate, a common active ingredient in Tums and other brands, is widely recommended because it’s effective, doesn’t cross the placenta, and even adds a little extra calcium to your daily needs. Magnesium hydroxide, found in Milk of Magnesia, is another option, but it’s best used sparingly, especially late in pregnancy, because too much magnesium can trigger contractions. On the flip side, avoid antacids with sodium bicarbonate, also called baking soda. It can cause fluid retention and high blood pressure, both risky during pregnancy. Aluminum-based antacids? Skip those too—they can lead to constipation and aren’t well studied in pregnant women.

It’s not just about picking the right pill. How you take it matters. Chewable tablets often work faster than liquids, and taking them 1 hour after meals and at bedtime gives the best relief. Don’t overdo it—more isn’t better. Too many antacids can mess with iron and other mineral absorption, which you need more of during pregnancy. If you’re still struggling after trying safe options, talk to your provider. Sometimes lifestyle changes—eating smaller meals, staying upright after eating, avoiding spicy or fatty foods—do more than any pill ever could.

Below, you’ll find real-world insights from women who’ve navigated this, along with clear breakdowns of what’s safe, what’s risky, and how to manage heartburn without guessing. No fluff. Just what works.