It is generally safe to take Tums (calcium carbonate) during pregnancy to relieve heartburn and indigestion, as long as it is used according to recommended dosages and guidance from a healthcare provider. Tums not only helps neutralize stomach acid but also provides supplemental calcium, which is beneficial during pregnancy. However, it is important not to exceed the recommended maximum daily dosage (usually up to about 10-15 tablets of regular strength per day) and avoid long-term use without doctor supervision. It is also advised to separate Tums from iron supplements by at least 1-2 hours to avoid interference with iron absorption. Potential side effects of excessive Tums use include constipation, risk of kidney stones, and possible interference with other mineral absorption.