The role of hormonal and immune changes in oral health during pregnancy

By Maria-Nefeli Tsoukatou and Petros Nasimpian

Introduction

Pregnancy induces significant physiological and hormonal changes that can profoundly affect oral health. During pregnancy, elevated levels of estrogen and progesterone affect a variety of oral health factors, including gingival tissue responsiveness, salivary composition, and the oral flora. These alterations may increase susceptibility to oral disorders such as gingivitis, periodontitis, and dental caries, affecting both maternal and fetal health. These findings underscore the importance of integrating oral health care into prenatal care routines.

This paper aims to deliver a comprehensive review of the physiological alterations impacting oral health during pregnancy, the related dangers, and the significance of preventive and therapeutic dental treatment. By comprehending these aspects, healthcare providers can enhance maternal and fetal health through integrated care methodologies.

Physiological Changes in Oral Health During Pregnancy

Pregnancy engenders a distinctive physiological condition characterized by significant hormonal, immunological, and metabolic alterations. These systemic changes significantly affect oral health, frequently aggravating existing disorders or leading to new diseases such as pregnant gingivitis, periodontitis, and dental caries. Understanding the mechanisms underlying these changes is critical for both medical and dental professionals aiming to protect maternal and fetal health.

Gingivitis and Periodontitis due to Hormonal Changes

When pregnancy occurs in a woman’s life, it brings about hormonal shifts that may significantly impact the physiology of her body. The reason many tissues undergo specific changes during pregnancy is the increased production of estrogen and progesterone by the placenta. Epithelial cells respond to the signaling of both steroid hormones through their receptors, which is why they exert profound effects on the growth, differentiation, and function of reproductive tissues (Arendt et al., 2015) (Diel P, 2002).

A) Pathophysiology of Gingivitis

The rising levels of estrogen and progesterone in the bloodstream are also responsible for increased vascular permeability and capillary dilation within tissues by affecting the endothelial cells lining the blood vessels. In addition to vascular permeability—particularly concerning oral health during pregnancy—progesterone contributes to the suppression of local immune defenses by reducing the effectiveness of macrophages and neutrophils against bacterial plaque. This weakened immune response encourages bacterial accumulation and gingival inflammation, increasing the risk of periodontal disease (Sachelarie et al., 2024).

B) Clinical manifestations of Gingivitis

Pregnant women often have gingival tissues that are more prone to inflammation. As a result, they may experience red and swollen gum papillae, which can sometimes bleed and be painful. In more rare cases, they may develop a localized, non-cancerous growth on the gums (pregnancy tumor), also known as a pyogenic granuloma (Yenen et al., 2019). Generally, gingivitis is a common condition during pregnancy. According to studies, it is estimated that 60–75% of pregnant women experience gingivitis—significantly more than postpartum or non-pregnant women (Hartnett et al., 2016). It usually appears around the second month of gestation, worsens over time, and resolves spontaneously after childbirth. However, this is the best-case scenario. If gingivitis remains untreated, it may progress to periodontitis—a more severe gum infection that can lead to tooth mobility and, eventually, tooth loss.

Tooth Damage due to Salivary Composition and Flow Rate

Saliva plays a crucial protective role in oral homeostasis, aiding in the remineralization of enamel, neutralizing acids, and controlling microbial populations. During pregnancy, several studies have reported alterations in salivary composition, including reduced flow rate and pH, particularly during the third trimester. These changes are thought to be hormonally driven and contribute to increased caries susceptibility due to prolonged acid exposure and diminished buffering capacity (Yang et al., 2024).

A) Tooth Decay

A critical issue women may face during pregnancy is tooth decay. More specifically, they may experience dental caries, cavities, and tooth erosion. Dental caries and cavities can result from several factors, including elevated estrogen levels and reduced saliva flow. Another contributing factor, especially during the early months of pregnancy, is the increased craving for specific foods such as carbohydrates, along with poor oral hygiene habits like infrequent brushing and flossing—often due to prioritizing the baby’s health over their own (Yenen et al., 2019).

B) Tooth Erosion

Tooth erosion is also commonly observed during pregnancy, primarily due to vomiting. Studies have shown that nausea and vomiting occur in approximately 70% of pregnancies, increasing the acidity in the oral cavity. The maternal enamel layer, when exposed to such an acidic environment, can be eroded, making teeth even more susceptible to caries. While saliva typically helps neutralize acid in the mouth, the decreased flow of saliva during pregnancy makes this protective mechanism less effective, rendering the problem difficult to avoid (Yenen et al., 2019) (Sachelarie et al., 2024).

Immune system modulation

Pregnancy induces a shift in the maternal immune system to favor fetal tolerance. Specifically, there is a transition from a Th1 (pro-inflammatory) to a Th2 (anti-inflammatory) cytokine profile, which impairs the body’s ability to mount effective immune responses to bacterial pathogens in the oral cavity. Regulatory T cells (Tregs) are upregulated, further diminishing the pro-inflammatory defense mechanisms required to control subgingival biofilms.

In addition to T cell modulation, innate immune responses are also affected. Polymorphonuclear leukocytes (PMNs), which are the first line of defense in periodontal tissues, exhibit reduced chemotactic activity and phagocytosis during pregnancy. This suppression compromises the host’s ability to respond to bacterial invasion, facilitating progression from gingivitis to periodontitis (Wen et al., 2023).

Microbial Shifts in the Oral Cavity

Hormonal fluctuations during pregnancy alter the oral microbiota, favoring the growth of specific pathogenic species. Notably, Prevotella intermedia, a gram-negative anaerobe associated with periodontal disease, utilizes estrogen and progesterone as growth factors. Consequently, its prevalence increases significantly during pregnancy, often in correlation with worsening gingival inflammation. Additional pathogens like Porphyromonas gingivalis and Treponema denticolahave also been shown to flourish in the altered immunohormonal environment of pregnancy, contributing to tissue destruction through the secretion of virulence factors such as gingipains and lipopolysaccharides (Wen et al., 2023).

Poor oral health’s effect on pregnancy

Pregnancy can trigger a range of physiological changes that, if left unaddressed, may lead to significant pathological conditions affecting both the mother and the fetus. Among these, periodontal disease—particularly pregnancy-associated periodontitis—appears to have a notable impact on the course and outcome of gestation.

Preterm Birth and Low Birth Weight

Multiple studies have demonstrated a significant association between periodontal disease and adverse pregnancy outcomes, such as preterm birth and low birth weight. Although the precise mechanisms underlying this correlation remain unclear, several plausible biological pathways have been proposed. One such mechanism involves hematogenous dissemination of periodontal pathogens to the uterine environment, potentially leading to intrauterine infection. This condition is implicated in approximately 25–40% of preterm births.

Another contributing factor is the systemic elevation of pro-inflammatory mediators, including tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6). Elevated concentrations of these cytokines in the feto-placental unit may induce premature rupture of membranes and stimulate uterine contractions, ultimately resulting in spontaneous or medically indicated preterm delivery.

A more controversial hypothesis suggests that increased levels of maternal IgM antibodies—produced in response to periodontal pathogens—may also play a role in preterm birth. This theory is supported by findings of elevated IgM concentrations in cord blood samples from preterm infants (Nannan et al., 2022).

Pre-eclampsia due to Systemic Inflammation

Another serious pregnancy complication potentially linked to poor oral health is pre-eclampsia, a hypertensive disorder characterized by new-onset high blood pressure, often accompanied by proteinuria, after 20 weeks of gestation. Pre-eclampsia can progress to more severe conditions such as eclampsia and HELLP (Hemolysis, Elevated Liver enzymes, Low Platelet count) syndrome. (Karrar et al., 2024) It is the third leading cause of maternal mortality, accounting for an estimated 76,000 maternal deaths globally each year. Similar to preterm birth, the pathophysiology of pre-eclampsia is believed to involve elevated levels of inflammatory cytokines originating from periodontal tissues. These inflammatory mediators can enter the maternal circulation, leading to systemic inflammation, oxidative stress, and vascular endothelial damage—processes that contribute to the development of pre-eclampsia, often described as an acute atherosis-like condition (Varashney et al., 2014).

Gestational Diabetes Mellitus

Furthermore, emerging evidence suggests a potential association between periodontitis and gestational diabetes mellitus (GDM). A meta-analysis conducted by Abariga and Whitcomb reported that women with periodontitis have a significantly increased risk of developing GDM compared to those without periodontal disease. However, despite these findings, the evidence remains inconsistent, and the proposed mechanism—chronic systemic inflammation—has yet to be conclusively established (Poulsen et al., 2019).

Given these associations, it is essential that pregnant individuals maintain optimal oral health as part of their prenatal care. Early diagnosis and management of periodontal disease may reduce the risk of adverse pregnancy outcomes and improve overall maternal and fetal health.

Maintaining Oral Health During Pregnancy: Guidelines and Safe Practices

Oral Hygiene Recommendations

Maintaining good oral hygiene is crucial during pregnancy to prevent gingivitis and periodontitis. The American College of Obstetricians and Gynecologists (ACOG) recommends the following practices: 

●      Brushing: Use toothpaste with fluoride to brush teeth twice daily.

●      Flossing: Floss daily to remove plaque between teeth.

●      Diet: Limit sugary foods and beverages to reduce plaque formation.

●      Dental Visits: Schedule regular dental check-ups.

Safe Dental Procedures During Pregnancy

Dental care is both safe and essential during pregnancy. Preventive, diagnostic, and restorative procedures, including dental radiographs (with suitable shielding) and local anesthesia (e.g., lidocaine with or without epinephrine), can be provided safely. Essential operations, like extractions, root canals, and fillings, should not be deferred, since delaying treatment may result in more intricate complications (Favero et al., 2021).

Medications Considered Safe During Pregnancy

Certain medications are deemed safe for use during pregnancy:

●      Pain Management: Acetaminophen is generally considered safe.

●      Antibiotics: Penicillin, amoxicillin, and clindamycin can be prescribed when necessary.

●      Anesthetics: Local anesthetics like lidocaine are safe when used appropriately.

However, all medications must be prescribed wisely, weighing the advantages against potential hazards.

Management and Prevention

Effective management of gingivitis and periodontitis during pregnancy includes:

●      Regular Dental Check-ups: Routine dental visits for professional cleaning and early detection of oral health issues.

●      Good Oral Hygiene Practices: Brushing three times daily with fluoride toothpaste and flossing to remove dental plaque.

●      Dietary Considerations: Consuming a balanced diet rich in vitamins and minerals to support oral health.

●      Smoking Cessation: Avoiding tobacco use, which can exacerbate periodontal disease.

●      Timely Treatment: Addressing any signs of gingivitis promptly to prevent progression to periodontitis.

In conclusion, preventing and treating gingivitis and periodontitis during pregnancy requires an understanding of their pathogenesis. Good oral hygiene habits and routine dental care are essential for preserving oral health and guaranteeing successful pregnancies.

The Impact of Diet on Oral Health During Pregnancy

Diet plays a crucial role in maintaining oral health during pregnancy, influencing both the maternal oral cavity and the developing fetus. Nutritional intake affects the oral microbiome, salivary composition, and the structural integrity of teeth and gums (Santonocito et al., 2022). The mechanisms by which diet affects oral health during pregnancy are examined in this part, with a focus on the value of a balanced diet in preventing dental conditions such gingivitis, periodontitis, and dental caries.

Nutritional Factors Affecting Oral Health

A) Macronutrients

●      Carbohydrates: High consumption of fermentable carbohydrates, particularly sugars, supplies substrates for cariogenic bacteria such as Streptococcus mutans, which produces acid and causes enamel demineralization. This effect is exacerbated by frequent use of sugary snacks and beverages, which increases the risk of dental caries during pregnancy.

●      Proteins and Fats: Adequate protein intake promotes tissue regeneration and immunological function, whereas healthy fats, such as omega-3 fatty acids, have anti-inflammatory characteristics that may improve periodontal health.

B) Micronutrients

●      Calcium and phosphorus: These minerals are essential for dental enamel stability. Dairy products, nuts, and seeds are abundant sources.

●      Vitamin D: Improves calcium absorption and bone health. Deficiency can reduce enamel development and increase vulnerability to dental cavities.

●      Vitamin C: Required for collagen synthesis and gum health. Deficiency can cause gingival bleeding and an increased risk of periodontal disease.

●      Vitamin A and E: Contribute to mucosal integrity and possess antioxidant characteristics that shield oral tissues from oxidative stress.

●      B Vitamins (e.g., Folate, B6, B12): Promote cellular metabolism and tissue healing. Folate ,in particular, is essential for fetal development and may alter dental health outcomes in offspring.

Dietary Recommendations for Optimal Oral Health During Pregnancy

To maintain good dental health throughout pregnancy, numerous evidence-based dietary and behavioral measures are recommended. A nutrient-dense diet rich in fruits, vegetables, whole grains, lean proteins, and low-fat dairy products strengthens the maternal immune system and ensures adequate intake of essential micronutrients like calcium, vitamin C, and vitamin D—factors important for periodontal health and fetal development. Concurrently, restricting sugary snacks, acidic foods, and sweetened beverages is critical to lowering the risk of enamel demineralization and dental caries, both of which are exacerbated during pregnancy by hormonal changes that impact the oral flora and salivary composition.  Maintaining appropriate hydration improves dental health by increasing salivary flow, which is essential for buffering acids and promoting remineralization. Regular dental check-ups are also vital since they allow for the early detection and treatment of problems such pregnancy gingivitis and periodontitis. Both the American Dental Association (ADA) and the American College of Obstetricians and Gynaecologists (ACOG) emphasize the safety and efficacy of preventive, diagnostic, and restorative dental care throughout pregnancy.

Intergenerational Impact of Maternal Nutrition on Offspring Oral Health

The maternal nutritional status during pregnancy has been connected to the dental health of the kids. Insufficient intake of important nutrients during pregnancy, such as vitamin D and folate, may raise the incidence of dental cavities in offspring. Providing proper diet throughout pregnancy can have long-term benefits for the oral health of the child (Rafisa et al., 2023).

Conclusion

Pregnancy introduces complex hormonal, immunological, and microbial changes that significantly impact oral health. These alterations increase the risk of conditions such as gingivitis, periodontitis, dental caries, and tooth erosion, which can affect both maternal and fetal outcomes. Evidence suggests a strong link between poor oral health and complications such as preterm birth, pre-eclampsia, and gestational diabetes. Maintaining oral hygiene, regular dental care, and adequate nutrition are essential components of prenatal care. An interdisciplinary approach involving dental and obstetric professionals is critical to improving both maternal and fetal health outcomes. Future research should aim to clarify mechanistic pathways and optimize preventive strategies.

References

American College of Obstetricians and Gynecologists. Oral Health Care During Pregnancy and Through the Lifespan: Committee Opinion No. 569. Obstetrics & Gynecology. 2013 Aug;122(2, Part 1):417–422.

Arendt, LM, and Kuperwasser, C. Form and function: how estrogen and progesterone regulate the mammary epithelial hierarchy. J Mammary Gland Biol Neoplasia. 2015 Jun;20(1-2):9-25.

Diel, P. Tissue-specific estrogenic response and molecular mechanisms. Toxicol Lett. 2002 Feb 28;127(1-3):217-24.

Favero, V., et al. Pregnancy and Dentistry: A Literature Review on Risk Management during Dental Surgical Procedures. Dent J (Basel). 2021 Apr 19;9(4):46.

Hartnett, E., et al. Oral Health in Pregnancy. Journal of Obstetric, Gynecologic & Neonatal Nursing. 2016;45(4):565–573.

Karrar, SA., et al. Preeclampsia. In: StatPearls [Internet]. 2024.

Nannan, M., et al. Periodontal disease in pregnancy and adverse pregnancy outcomes: Progress in related mechanisms and management strategies. Front. Med. 2022;9:963956.

Poulsen, H., et al. Oral Health in Women with a History of High Gestational Diabetes Risk. Dent J (Basel). 2019 Sep 3;7(3):92.

Rafisa, A., et al. The Association Between Maternal Nutritional Status During Pregnancy and Caries Experience in Their Offspring: A Literature Review. European Journal of Medical and Health Research. 2023;1(2):85-90.

Sachelarie, L., et al. Impact of Hormones and Lifestyle on Oral Health During Pregnancy: A Prospective Observational Regression-Based Study. Medicina (Kaunas). 2024 Oct 30;60(11):1773.

Santonocito, S., et al. A Cross-Talk between Diet and the Oral Microbiome: Balance of Nutrition on Inflammation and Immune System's Response during Periodontitis. Nutrients. 2022 Jun 11;14(12):2426.

Varshney, S., and Gautam, A. Poor periodontal health as a risk factor for development of pre-eclampsia in pregnant women. J Indian Soc Periodontol. 2014 May;18(3):321-5.

Wen, X., et al. The Bidirectional Relationship Between Periodontal Disease and Pregnancy. Frontiers in Microbiology. 2023;14

Yenen, Z., and Ataçağ, T. Oral care in pregnancy. J Turk Ger Gynecol Assoc. 2019 Nov 28;20(4):264-268.

Yilmaz, F., et al. The effects of pregnancy on oral health, salivary pH and flow rate. BMC Oral Health. 2024 Oct 25;24(1):1286.