Pregnancy is commonly associated with dental problems, but the underlying reasons have remained unclear. New research suggests that significant changes in a woman’s oral microbiome – the community of bacteria in the mouth – during pregnancy may contribute to increased risk of tooth decay and gum disease. These shifts happen rapidly, compressing years of natural microbiome evolution into just nine months.
Microbiome Disruption During Pregnancy
Researchers at Bar-Ilan University in Israel, led by Yoram Louzoun, analyzed saliva samples from 346 pregnant women across all three trimesters. The study found a consistent decline in oral microbiome diversity as pregnancy progressed. Specifically, there was a reduction in Akkermansia muciniphila, often considered a beneficial bacterium, alongside an increase in species linked to inflammation, such as Gammaproteobacteria and Synergistota.
The study was corroborated by similar findings from an independent cohort of 154 pregnant women in Russia, reinforcing the robustness of the observed microbiome shifts. The changes aren’t necessarily new, but compressed: “Pregnancy is like a fast-forward of that very slow evolution,” Louzoun explains.
Factors Influencing Microbiome Changes
Multiple factors likely drive these changes. Hormonal fluctuations, increased inflammation, dietary shifts, and cessation of certain medications all play a role. The study found correlations between microbiome composition and lifestyle factors such as gluten-free diets, antibiotic use, stress levels, and smoking history (even if the woman quit smoking during pregnancy). These influences highlight the complex interplay between the body and its bacterial environment during this critical period.
Implications for Maternal and Infant Health
The connection between oral microbiome changes and pregnancy-related dental issues isn’t fully understood, but researchers suggest that saliva acidity may also increase during pregnancy, further altering bacterial species. Experts at King’s College London note that these microbial shifts could have broader implications for both maternal and fetal health. The oral microbiome interacts with the immune system, potentially influencing long-term inflammatory status, allergy risk, and susceptibility to infections in both the mother and child.
Future Research and Preventive Measures
Louzoun suggests that establishing a baseline for a healthy pregnancy microbiome could allow early detection of deviations. Better understanding how to maintain a balanced oral microbiome through diet, hygiene, and lifestyle choices could have lasting benefits. “Changes to the microbiome might determine a parent’s inflammatory status and help prime the child’s immune system,” says Lindsey Edwards.
Ultimately, these findings underscore the importance of oral health during pregnancy, not just for the mother’s teeth but also for the well-being of her developing child.
