Generic Name: Antacids – magnesium hydroxide or calcium carbonate.
Indications: Acid indigestion, heartburn, sour stomach, constipation or calcium deficiency.
FDA Drug Category: B – magnesium hydroxide; C – calcium carbonate.

Summary Recommendations
Antacids are over-the-counter medications used to treat indigestion and heartburn during pregnancy. The medications can also be suggested to treat constipation and sour stomach. Calcium carbonate can be used to increase calcium intake if calcium deficiency exists. The brand name for magnesium hydroxide is Maalox. The brand name for calcium carbonate is Tums.

General Precautions
Magnesium hydroxide and calcium carbonate are generally considered safe for use during pregnancy. It is best to use the medications only as prescribed and only when directed by your physician. Magnesium is not readily absorbed during pregnancy, so calcium-based antacids are often suggested in place of magnesium-based products. However, calcium carbonate – also known as Tums is in the pregnancy safety category C, which means infrequent use is best due to lack of human-based studies proving safety during pregnancy.

If you are taking prescription medications, especially anticoagulants, consult your obstetrician or health care provider before taking an antacid.

Effect While Trying to Conceive
There is no known connection between antacids and infertility, but there is some question as to the effect of aspartame on fertility. Aspartame is a chemical sweetener commonly used in sugar-free antacids. It may be best to choose antacids that contain sugar to reduce any impact chemical sweeteners may have on fertility and chances of conception.

Effects on Pregnancy
Indigestion is common during pregnancy and most obstetricians openly suggest taking antacids for relief. There is no danger of birth defects associated with infrequent antacid use, but long-term, heavy use has not be studied during pregnancy, so women should use antacids as needed to treat symptoms unless calcium carbonate is suggested as a calcium supplement.

Safe During Breastfeeding
There are no precautions listed for antacid use during pregnancy. While levels of magnesium and calcium in the maternal body increase and some of the minerals pass to baby in breastmilk, there are no side effects associated with increased mineral intake from breastmilk. The amount of calcium and magnesium passed in breastmilk is no more than that found in infant foods, formulas and cereals.