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A new study looked at OTC drugs and their impact on pregnancy. Getty Images
  • An OTC drug used for acid reflux may help pregnant women.
  • Lansoprazole, a proton pump inhibitor (PPI) sold under the brand name Prevacid, is commonly used during pregnancy and generally deemed safe.
  • More experimental and animal studies need to be done to gain a better understanding of how drugs may reduce the risk of preterm labor.

A popular over-the-counter (OTC) drug used to treat acid reflux and heartburn may have the potential to reduce preterm birth.

Lansoprazole, a proton pump inhibitor (PPI) sold under the brand name Prevacid, is commonly used during pregnancy and generally deemed safe.

Lansoprazole is listed as a Category B drug by the Food and Drug Administration. It’s said not to cause fetal harm, but there is limited research on it in human pregnancies.

A recent study in JCI Insight examined 13 FDA-approved drugs believed to be safe during pregnancy.

The drugs work different ways in the human body, but researchers looked at them because the biological pathway in them in affects the body’s immune response — a factor in preterm birth.

“Inflammation clearly plays a role in initiating labor and preterm birth,” said Marina Sirota, PhD, senior author and an assistant professor of pediatrics at University of California San Francisco.

“Immune pathways are very significantly dysregulated in women who end up delivering preterm, and they’re also dysregulated in babies who are born early.”

The researchers looked at which genes were up- or downregulated (increased or decreased) in the blood cells of women who had a spontaneous preterm birth. That helped them identify a gene expression “signature.”

Then they searched for the opposite signature in cells that had been exposed to 1,309 different drugs. They believed that a drug that could correct the effects that preterm birth had on the women’s blood cells may also be able to prevent preterm birth.

They whittled the list down to 13 drugs that weren’t found to have pregnancy risks in human or animal trials.

Next, they ranked the medications to develop what they called a reversal score. The reversal score was a measure of the extent that the drugs could reverse the gene expression associated with preterm birth.

The other drugs identified included progesterone, which is used to treat recurrent spontaneous preterm birth, and folic acid, which can prevent birth defects.

Three antibiotics, and an antifungal, an antidepressant, an antidiabetic, and a blood pressure medication were also on the list.

The team chose to further test lansoprazole due to its high reversal score and the fact that it’s available OTC. They knew it affected a stress-response protein — heme oxygenase-1 — that has been linked with pregnancy disorders.

To better understand that link, the scientists gave pregnant mice a bacterial component to induce inflammation, which causes some fetuses to die in utero.

But when the mice were given lansoprazole, they had more viable fetuses. In fact, lansoprazole worked better in these mice than progesterone, the other preterm birth treatment.

Does this mean that popping some Prevacid may prevent preterm birth? That hasn’t been proven, the researchers emphasize. More research, especially in humans, would need to be done to prove that it could prevent preterm birth, the authors say.

“This was done in mice only, and results may not be generalized to humans,” noted Dr. Ziyad Al-Aly, an assistant professor at Washington University in St. Louis. He has researched PPIs but wasn’t involved in the study.

More experimental and animal studies need to be done to gain a better understanding of how PPIs may reduce the risk of preterm labor.

If those are successful, human studies would then be needed to determine if the medication worked in humans to prevent preterm birth.

“We really don’t know if this is going to be effective in humans,” Al-Aly added.

Another issue surrounding the buzz from the study is that some people aren’t sure that lansoprazole is safe for pregnant women to take.

Jean Golding, PhD, a pediatric and perinatal epidemiology professor at University of Bristol (she wasn’t affiliated with the study), told Healthline it’s unclear if lansoprazole is safe during pregnancy. Some research has called for more studies to confirm that PPIs can be taken while pregnant without causing harm to the fetus.

There are very few longitudinal studies that have followed up on a sufficient number of children whose mothers took lansoprazole while pregnant.

This means there’s little data available to assess whether they aren’t at risk of disorders, such as autism or asthma or other cognitive or behavioral difficulties, if their mothers had taken the medication in pregnancy, Golding said.

“I suggest that women should be advised that taking any medication in pregnancy, even acetaminophen, has risks for the unborn child’s development,” Golding said. Acetaminophen is another drug — not a PPI — that has come into question for use by pregnant women.

Dr. Tina M. Dumont, an OB-GYN specializing in maternal and fetal medicine at UMassMemorial Health Care in Massachusetts, told Healthline that existing data hasn’t shown that lansoprazole causes significant harm to fetuses.

“For any drug, however, there is always the possibility of risks that have just not yet been identified. It is always important to weigh the benefits of taking a medication against any risk it might have,” she said.

“Results, while encouraging, are still several steps away before we know if this will be an effective and safe treatment in human pregnancy and which patients are likely to benefit,” Dumont added.