Mouthwash Use in Pregnancy Linked to Better Outcomes

You’ve heard of mouthwash to fight bad breath. But what about mouthwash to fight preeclampsia and preterm birth?

Scientists at the Ohio Collaborative, a March of Dimes Prematurity Research Center (PRC) encompassing Cincinnati Children’s Hospital Medical Center, Case Western University, and Vanderbilt University, have presented preliminary findings linking the use of over the counter, non-alcoholic mouthwash in pregnancy with a reduction in several dangerous prenatal complications, from preeclampsia to preterm birth.

The research found that mouthwash use throughout pregnancy dramatically reduced rates of hypertensive disorders in pregnancy, including preeclampsia, and rates of a serious prenatal bacterial infection called chorioamnionitis. Mouthwash use was also linked with modest reduction of preterm birth. All the reductions were seen in women with low socioeconomic status at risk of having oral health disorders, including gingivitis or periodontitis.

Ohio PRC investigator Dr. Braxton Forde, who is also a maternal-fetal medicine specialist at the Cincinnati Fetal Center, collaborated on the study with PRC principal investigator Dr. Sing Sing Way, PRC scientist Dr. Elizabeth Kelly, and Dr. Samuel Perry, who co-leads the March of Dimes PRC at the University of Pennsylvania (UPenn).

Dr. Forde said the reductions may result from the mouthwash’s elimination of oral bacteria that can stimulate inflammation in the mouth and other tissues in expecting mothers.

Presenting the data last month at the annual meeting of the American College of Obstetricians & Gynecologists (ACOG) in Washington, D.C., Dr. Forde said the intervention showed remarkable success.

Offering more than 1,200 pregnant women attending prenatal visits in Cincinnati free bottles of Crest Pro-Health, an over-the-counter mouthwash containing a bacteria killing ingredient called cetylpyridinium chloride, reduced preeclampsia rates by 25%, neonatal intensive care unit admission rates by 35%, chorioamnionitis rates by over 40%, and shifted average gestational age at delivery by two days, he said.

The reductions were observed after Dr. Forde’s team compared the outcomes of the women who received mouthwash at their prenatal visits with the outcomes of pregnant women who visited the same clinics the year prior and were not offered free mouthwash.

Specifically, the mouthwash cohort had a preeclampsia rate of 12% compared to 16% in the non-mouthwash cohort at the same clinics the year prior. The chorioamnionitis rate in the study group was 4% compared to 7% in the group that was not given mouthwash the previous year. While the preterm birth rate was only modestly reduced, a closer look showed babies whose mothers were given mouthwash stayed in the womb for on average two additional days.

Dr. Forde acknowledged that though the trial was not a randomized controlled trial, and more of a “real-life healthcare initiative” whose results still need validation through rigorous future trials. He said the preliminary signal was striking and “the reductions were quite staggering.”

“To have these types of reductions in hypertensive pregnancy disorders and chorioamnionitis are huge, and moving the gestational age at delivery curve by two days is an extremely meaningful and beneficial shift for neonatal outcomes and for the healthcare system,” he said. “The savings garnered from avoiding the neonatal intensive care unit for just one day could supply an obstetrical clinic with free mouthwash for a year.”

Study participants, the vast majority of which were receiving Medicaid and were at high risk for hypertensive pregnancy disorders, gestational diabetes, and oral disease like gingivitis and periodontitis, were recruited before 20 weeks of pregnancy.

Patients were told to use the mouthwash twice daily, given instructions on brushing their teeth and maintaining healthy hygiene habits, and handed additional mouthwash at each subsequent visit, with all participants receiving mouthwash for at least one full trimester, and many for the entire pregnancy.

“We flooded the clinics with free mouthwash, and patient interest was extremely high,” Dr. Forde said, adding that in their highest volume clinic, the average study participant used about five bottles of mouthwash during their pregnancy.

“In analyzing the results, no matter which patient population we looked at in terms of clinic location, we saw a similar trend: a very large reduction in hypertensive pregnancy disorders and preeclampsia, a reduction in chorioamnionitis, and an improvement in gestational age at delivery, which we think was driven by the reduction in hypertensive pregnancy disorders and preeclampsia.”

Dr. Forde said the study was the first to probe whether mouthwash could help reduce adverse pregnancy and birth outcomes by targeting patients at risk of dental disease in pregnancy on a population level, rather than waiting for expecting mothers to be diagnosed with severe gingivitis and periodontitis.

All previous research on this subject, he said, involved patients after a diagnosis of periodontitis or severe gingivitis, and the vast majority involved dental cleaning as part of the intervention. Interestingly, he said, mechanical dental cleaning sometimes showed worsening adverse pregnancy outcomes, which were mitigated in studies that incorporated concurrent use of mouthwash. This inspired the current mouthwash project investigating the effects of mouthwash use alone.

“Every study done so far has included the dentist, which for Medicaid patients, is often logistically and practically difficult for a variety of reasons,” Dr. Forde said. “So we looked at the data, which shows that more than 80% of low socioeconomic status pregnant women are going to have dental disease, and reasoned that if a lot of our patients will have their baby before they can even get in to the dentist, and we know this mouthwash is safe, we should find ways to just give it to them.”

Dr. Forde said more research is needed, but a possible reason that mouthwash is more effective than plaque removal at reducing adverse pregnancy outcomes in women at risk of dental disease might be counter intuitive.

“You might think that removing plaques through a dental procedure called root scaling would be more effective than mouthwash, but one consideration is that larger amounts of bacteria in our mouths are likely dislodged and seed into our bodies when dental plaques and decay are mechanically removed, potentially causing increased inflammation throughout the body,” he said. “With an antimicrobial, you are killing that bacteria on the spot.”

The mouthwash project was conducted in collaboration with the UPenn PRC, which is currently in the process of finalizing data analysis from a parallel study that also showed reductions in adverse pregnancy outcomes. Dr. Forde said he, together with Ohio PRC Drs. Kelly and Way, and UPenn PRC Dr. Perry, plan to submit the data and findings for peer review and publish both sets of data soon. The scientists are also planning their future work to further investigate how something simple like mouthwash can cause such profound reductions in adverse outcomes.