Barbara TritzShe was eight months pregnant. I collected a sample of her oral biofilm, placed it under the microscope, and started looking. What I saw immediately changed the way I thought about the appointment.
The field was filled with highly motile spirochetes. White blood cells were visibly active. At one point, I watched what appeared to be a spirochete interacting closely with a red blood cell. Was it playing with the red blood cell or attacking it?
I want to be very careful about what a chairside microscope can and cannot tell us. I cannot identify the species of a spirochete simply by looking at its shape and movement under the microscope. I cannot look at one slide and conclude that an organism has entered this woman’s bloodstream, crossed the placenta, or caused a pregnancy complication. Nor can I predict from one biofilm sample whether her baby will be born early, small, or perfectly healthy.
But I can see something else. This oral ecosystem is communicating: loudly and emphatically. I can see dysbiosis. I can see an active host immune response. I can see a microbial environment that deserves more attention than a quick polish and a reminder to floss. And in this particular patient, I was not looking at just one person.
There were two patients in my chair.
Pregnancy changes the oral environment. Hormonal changes can amplify the gingival inflammatory response to biofilm, and gingival bleeding during pregnancy is common. But I worry that because it is common, we sometimes begin to treat it as inconsequential.
“Pregnancy gingivitis.”
“Your hormones are making your gums bleed.”
“It will settle down after the baby comes.”
Perhaps. But bleeding is still communication. Inflammation is still communication. And pregnancy is not the time to stop asking why.
Pregnancy Gingivitis Should Not Mean “Ignore the Bleeding”
The American College of Obstetricians and Gynecologists recognizes that periodontal disease is common during pregnancy and recommends oral-health assessment and appropriate dental care during pregnancy. Dental treatment, including periodontal care, is considered safe during pregnancy. So why are so many pregnant women still receiving what amounts to little more than a routine cleaning? I believe we can do better.
What Does the Research Say?
Periodontal disease has repeatedly been associated in observational research with adverse pregnancy outcomes. A 2022 systematic review and meta-analysis found a significant association between periodontitis and preeclampsia. Another systematic review involving more than 15,000 participants found associations between maternal periodontal disease and both preterm birth and low birth weight. An overview of multiple systematic reviews has also reported associations between periodontitis and outcomes including preterm birth, low birth weight, gestational diabetes, and preeclampsia.
That does not mean periodontal disease has been proven to cause these complications. Association does not equal causation, and we should never tell a pregnant woman that periodontal disease will cause preeclampsia or that treating her gums will guarantee a full-term, healthy baby.
The clinical-trial evidence is more complicated. Periodontal treatment during pregnancy improves maternal oral health and is considered safe, but trials have not consistently demonstrated reductions in preterm birth or low birth weight. Some more recent reviews suggest periodontal treatment may reduce certain adverse outcomes, while others remain uncertain.
To me, that uncertainty does not make oral inflammation less important. It makes early identification more important.
The Mouth Does Not Operate in Isolation
The mouth is not an isolated compartment. Inflamed periodontal tissues are highly vascular. Everyday activities such as chewing, brushing, flossing, and periodontal instrumentation can transiently introduce oral bacteria or bacterial products into the bloodstream, particularly when gingival tissues are inflamed.
Researchers have proposed two major pathways that may help explain the association between periodontal disease and pregnancy complications. One is hematogenous dissemination, in which oral microorganisms or their components enter the circulation and potentially reach distant tissues. The other is systemic inflammation, in which periodontal disease contributes inflammatory mediators that may influence tissues beyond the mouth.
Oral organisms have also been detected in placental tissues in research studies. Fusobacterium nucleatum has been reported in placental samples, and other research has explored organisms including Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Prevotella intermedia in pregnancy and periodontal disease.
Pregnancy hormones do more than make gingival tissues “sensitive.” Rising estrogen and progesterone alter vascular permeability, connective-tissue metabolism, immune signaling, and the microbial environment of the gingival sulcus. Certain organisms appear to benefit directly from these hormonal changes. Prevotella intermedia, for example, can use pregnancy-associated steroid hormones as growth-promoting factors, and research has demonstrated increases in this organism during pregnancy. Laboratory studies also suggest that estradiol can enhance biofilm-related behaviors such as polysaccharide production and bacterial coaggregation. In other words, pregnancy does not simply change the gums—it can change the ecological terrain in which the oral microbiome lives.
That may help explain why an oral biofilm that was previously tolerated can provoke a much more inflammatory response during pregnancy—and why looking closely at the microbiome matters.
Again, finding oral organisms or bacterial DNA in placental tissues does not prove that those organisms caused an adverse pregnancy outcome. But it certainly challenges the outdated idea that the mouth and the rest of the body function as separate systems.
They do not.
What the Microscope Can—and Cannot—Tell Us
When I look at this patient’s slide, I am not diagnosing Treponema denticola by sight. Spirochetes share characteristic corkscrew morphology and movement, but species identification requires molecular testing or another validated laboratory method. I am also not claiming that the organism I watched beside a red blood cell was literally “attacking” that cell in a way that predicts systemic disease.
What I can say is that I saw a biofilm containing an unusually active spirochetal population alongside substantial immune-cell activity.
And that tells me one thing very clearly: Look deeper.
The microscope is not the final diagnosis. It is information. It is a reason to examine periodontal probing depths, bleeding, attachment levels, plaque maturity, medical history, blood-pressure history, nutrition, airway, home care, and systemic risk. It may also be a reason to consider validated microbial or inflammatory testing when clinically appropriate.
This is what I mean when I say:
Seeing the unseen changes the conversation.
Every Pregnant Patient Deserves More Than a Cleaning
I would like dental hygiene to rethink the phrase “pregnancy cleaning.”
A pregnant woman deserves a comprehensive periodontal assessment. Look at the bleeding pattern. Complete periodontal charting. Assess attachment loss. Evaluate biofilm burden and maturity. Ask about previous periodontal disease. Ask about smoking, diabetes, hypertension, nutrition, reflux, sleep, airway, and home care. Ask whether her gums were bleeding before pregnancy or whether something has changed.
Testing does not necessarily mean that every pregnant woman needs a commercial salivary PCR panel or chairside microscopy. But every pregnant patient does deserve to be evaluated for periodontal health, not simply scheduled for a cleaning. And if you don’t test, you are truly guessing…
Why Wait Until the Third Trimester?
And ideally, this conversation should begin before pregnancy.
If periodontal inflammation and dysbiosis may influence pregnancy biology, why wait until the eighth month to discover them?Preconception oral health deserves a place beside folate, blood pressure, glucose control, nutrition, smoking cessation, and other conversations we already consider essential to pregnancy preparation.
Expand the Lens
Dental hygienists spend more time looking directly at gingival tissues than any other healthcare professional. We see bleeding. We see suppuration. We see biofilm. We see inflammation. We hear about medications, pregnancy, menopause, diabetes, sleep, reflux, stress, diet, and systemic health. What if we stopped viewing those pieces as unrelated?
What if periodontal charting were not simply documentation for insurance? What if bleeding were not something we normalized? What if a microscope, microbial assay, inflammatory marker, or careful medical history sometimes gave us the clue that caused us to look deeper? What if dental hygiene appointments became genuine health assessments of the mouth as part of the body?
Because periodontal pathogens do not know where dentistry ends and medicine begins. Neither does inflammation.
Two Patients. One Opportunity to Look Deeper.
That microscope slide belongs to one woman. But when she sat in my chair eight months pregnant, I could not help thinking about the other patient I could not see.
Her baby.
I cannot promise that identifying and treating oral inflammation will prevent preeclampsia. I cannot promise that it will prevent preterm birth. I cannot promise that it will prevent a low-birth-weight infant. The science does not give us permission to make those promises.
But I also refuse to believe that the appropriate response to an inflamed, dysbiotic oral environment during pregnancy is:
“Don’t worry. Pregnancy makes gums bleed.”
We can do more than that.
We can identify disease earlier. We can reduce oral inflammatory burden. We can educate. We can collaborate. We can communicate with obstetric providers. We can encourage periodontal health before conception, not just during the final months of pregnancy. And we can stop thinking of dental hygiene as simply cleaning teeth.
The mouth is connected to the body.
And when a pregnant woman sits in our chair, we are caring for two patients. Sometimes expanding our lens may be one of the most important things we do.
Warmly,
Barbara
Queen of Dental Hygiene
Connecting the Mouth to the Body—One Patient at a Time
References
- American College of Obstetricians and Gynecologists. Oral Health Care During Pregnancy and Through the Lifespan. Committee Opinion No. 569.
- Iheozor-Ejiofor Z, Middleton P, Esposito M, Glenny AM. Treating periodontal disease for preventing adverse birth outcomes in pregnant women. Cochrane Database Syst Rev. 2017;6:CD005297.
- Arbildo-Vega HI, Padilla-Cáceres T, Caballero-Apaza L, et al. Effect of Treating Periodontal Disease in Pregnant Women to Reduce the Risk of Preterm Birth and Low Birth Weight: An Umbrella Review. Medicina. 2024;60(6):943.
- Le QA, Akhter R, Coulton KM, et al. Periodontitis and Preeclampsia in Pregnancy: A Systematic Review and Meta-Analysis. Maternal and Child Health Journal. 2022.
- Ye C, Katagiri S, Miyasaka N, et al. Oral bacteria in placental tissues: increased molecular detection in pregnant periodontitis patients. Oral Diseases. 2015.
- Usin MM, Tabares SM, Parodi RJ, Sembaj A. Periodontal conditions during pregnancy associated with periodontal pathogens. Journal of Investigative and Clinical Dentistry. 2013.
- Figueiredo MGOP, Takita SY, Dourado BMR, et al. Periodontal Disease and Adverse Neonatal Outcomes: A Systematic Review and Meta-Analysis. Frontiers in Pediatrics. 2022.
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