Pretty much every mom has experienced the unpleasantness of acid reflux during pregnancy, thanks to progesterone. The hormone relaxes muscles during pregnancy—meaning the stomach valve can become relaxed too—and that’s what can cause heartburn. That, and your growing baby crowding your stomach, pushing acid toward your esophagus.
But should you think twice before reaching for the heartburn medication while pregnant? Maybe, says a new study published in the Journal of Allergy and Clinical Immunology.
Researchers from the Asthma UK Center for Applied Research at the University of Edinburgh in Scotland pooled and analyzed data from eight studies, including more than 1.3 million kids, and found that the ones whose moms were prescribed medications for acid reflux while pregnant were one-third more likely to develop asthma symptoms.
Medications typically prescribed to treat the heartburn, known as H2-receptor antagonists and proton pump inhibitors, are part of the same drug classes that include Pepcid, Prilosec, Nexium, Zantac and Tagamet, to name a few. These medications aimed at treating acid reflux are cleared as safe for pregnant moms because previous research has found they do not affect a baby’s development in utero.
Although researchers say this study doesn’t prove the medicine is what caused asthma, it does mean there’s a need for more research to explore the link. They don't know if there's some other undiscovered link that could cause both acid reflux during pregnancy and a tendency for the baby to develop symptoms of asthma later on. Other research in the past has also suggested a link but more research could help establish whether the link is casual coincidence or something else.
Heartburn medications might not be the only variable, though. A 2016 study released by the Norwegian Institute of Public Health also found that even limited amounts of over-the-counter painkillers such as Tylenol taken during pregnancy increased risk by 13 percent of their child developing asthma by age 3.
For now, pregnant women who have been prescribed medication for acid reflux by their doctors should continue doing so, according to the study's authors, and consult with their physician about what's best for them to treat their pregnancy heartburn.