Is rennies safe during pregnancy?

Sounds fine: Rennies are calcium carbonate and magnesium carbonate, which neutralize stomach acid as a treatment for heartburn. Normal use of Rennies should be fine in pregnant women, but one can check with her Ob-Gyn doctor. Most doctors who do prenatal care have a printed handout (or online) that lists the common medications allowed for treating common symptoms at home... such as heartburn.