Heartburn is very common during pregnancy so the woman and her physician should discuss this problem and the best method and antacid that would be helpful. Antacids can be used indefinitely if they are only taken occasionally. However, when they are necessary several times a day, medical attention is required. Excessive antacid use in the short-term may indicate an underlying disorder that needs different care. The long-term, heavy use of any antacid can produce medical problems and should not be done without a physician's input.
Most antacids produce only minor side effects, especially if they are used infrequently.
Minor side effects are usually relieved by reducing the dose or frequency. For major side effects, contact the physician immediately. Calcium carbonate is a good antacid and provides calcium, which is desirable. Adults need 1500 mg a day and post menopausal females even more. Unless you drink a quart of milk a day, you likely do not get enough calcium from your food.