Is baking soda for heartburn safe during pregnancy?

What does the evidence say about baking soda for heartburn during pregnancy?

1. Antacids are meant for mild symptoms. NIDDK advises against using them every day or for severe symptoms except after discussing that use with your doctor, notes they can cause diarrhea or constipation, and puts head-of-bed elevation at 6 to 8 inches among the lifestyle changes for reflux. 1
2. Oral sodium bicarbonate is approved over the counter for heartburn, acid indigestion and upset stomach, sold as baking soda and effervescent granules, with standardized formulations of 325 mg powder and 650 mg tablets. The sodium load is measurable: one gram contains 11.9 mEq of sodium and bicarbonate ions and a single 650 mg tablet carries 7.7 mEq. It must be given judiciously to anyone with congestive heart failure, significant kidney disease, or sodium retention, because it worsens sodium retention and edema. 2
3. Pregnancy data is the gap. StatPearls advises clinicians to weigh the risks and benefits of sodium bicarbonate in pregnancy because comprehensive human data is unavailable, and notes a potential risk of fluid retention based on how the drug works. Excess bicarbonate can also produce metabolic alkalosis. 2
4. Heartburn in pregnancy has a worldwide incidence of 17 to 80 percent and can occur in all trimesters. Increased circulating progesterone relaxes the lower esophageal sphincter and the enlarging uterus raises intra-abdominal pressure, and the standard advice is smaller meals, chewing gum, not eating late at night, and elevating the head of the bed. 3
5. Calcium carbonate, the antacid most pregnant people reach for instead, is not expected to increase the chance of birth defects above the background risk when used as directed and within recommended amounts, though excessive intake can cause milk-alkali syndrome. 4

Is baking soda for heartburn safe in each trimester?

• First trimester. Heartburn can start early because rising progesterone relaxes the lower esophageal sphincter. A kitchen spoonful of baking soda is an unmeasured dose, which is the first problem with it: the pharmacy formulations are standardized at 325 mg powder and 650 mg tablets, and a spoon is neither.
• Second trimester. Symptoms usually climb as the growing uterus raises intra-abdominal pressure. This is the stage to build the non-drug habits the Cochrane review lists: smaller meals, chewing gum, not eating late at night, and elevating the head of the bed.
• Third trimester. The trimester where swelling is already on your mind, and the one where the sodium load matters most. Sodium bicarbonate has to be given carefully to anyone with sodium retention because it worsens edema, which is a conversation to have with your provider before making it a nightly habit.