In what is thought to be the first study to directly link prenatal stress hormones with primary tooth eruption, US researchers have said that, among mothers from socio-economically disadvantaged backgrounds, those with high prenatal levels of the stress hormone cortisol tended to have children whose primary teeth erupted earlier.
The findings suggest early tooth eruption may be an early indicator of accelerated biological ageing associated with socio-economic deprivation and prenatal stress, reports Dental Tribune.
“We show that a mother’s higher levels of stress-related hormones, particularly of cortisol, during late pregnancy are associated with the earlier eruption of primary teeth in her infant,” lead author Dr Ying Meng, an associate Professor in the University of Rochester School of Nursing, said of the research findings.
Meng and her colleagues analysed data from a birth cohort of 142 socio-economically disadvantaged mothers in the US who were pregnant between 2017 and 2022 and enrolled through the University of Rochester Medical Centre.
All infants were born at full term.
In the late second and third trimesters of pregnancy, each woman provided a saliva sample, and levels of cortisol, oestradiol, progesterone, testosterone, triiodothyronine and thyroxine were measured. The researchers then assessed the timing and number of erupted primary teeth at two, four, six, 12, 18 and 24 months of age.
Tooth eruption showed high variability across the first 24 months. By six and 12 months of age, respectively, 15.2% of the children had between one and six erupted teeth, and 97.5% had between one and 12.
All children had between three and 20 erupted teeth by 18 months of age, and by 24 months, just 25% had a full primary dentition.
In 2.7% of children, a sudden spurt in eruption occurred between 12 and 18 months, whereas the remainder showed a more continuous, although irregular, eruption pattern.
Early eruption did not reliably predict the number of teeth present at later visits.
During pregnancy, 36.6% of the women had a diagnosis of depression or anxiety. However, the researchers found that this diagnosis was not associated with their hormone levels or with the number of erupted teeth in their children at any time point.
Importantly, higher salivary cortisol levels in late pregnancy were associated with a greater number of erupted teeth by six months of age. Infants of mothers with the highest cortisol levels had, on average, four more erupted teeth at this age than infants of mothers with the lowest cortisol levels.
“High maternal cortisol during late pregnancy may alter foetal growth and mineral metabolism, including the regulation of levels of calcium and vitamin D, both essential for mineralisation of bone and teeth. Cortisol is also known to influence the activity of so-called osteoblast and osteoclast cells, responsible for building up, shaping and remodelling bone,” Meng said.
She aded that these results were further evidence that prenatal stress can speed up biological ageing in children.
‘Premature eruption of teeth could thus serve as an early warning sign of an infant’s compromised oral development and overall health, associated with socio-economic deprivation and prenatal stress.”
The authors also reported an association between maternal levels of the sex hormones oestradiol and testosterone and a greater number of erupted teeth at 12 months of age, although this relationship appeared weaker.
Similarly, weak yet statistically significant positive associations were found between maternal progesterone and testosterone levels and the number of erupted teeth at 24 months and between maternal triiodothyronine levels and the number of erupted teeth at 18 and 24 months.
Oestradiol, progesterone and testosterone play key roles in foetal development and birth weight. The authors suggested that this may explain how higher levels of these hormones could influence the timing of tooth eruption.
“We still have key questions that need answering, for example which maternal hormones or downstream developmental pathways drive the change in the timing of tooth eruption, what the exact relationship is between accelerated eruption of teeth and biological ageing and development, and what such speeding up says about a child’s general health,” Meng concluded.
The study was published in Frontiers in Oral Health.
Study details
Prenatal maternal salivary hormones and timing of tooth eruption in early childhood: a prospective birth cohort study
Ying Meng, Ruqian Yang, Nora Alomeir et al.
Published in Frontiers in Oral Health on 18 November 2025
Background
Although the mechanisms underlying tooth eruption are not fully understood, the prenatal maternal milieu, particularly stress exposures, appears to play an important role in dental development. Yet, limited research has investigated the influence of prenatal stress and stress-related hormones on tooth eruption.
Methods
This study included 142 mother-child dyads from a birth cohort to examine associations between prenatal stress, stress-related hormones, and primary tooth eruption. The number of erupted teeth was assessed by dentists at child visits through 24 months of age. Maternal prenatal depression and anxiety diagnoses were extracted from medical records as a proxy for stress. Stress-related hormone concentrations, including cortisol, estradiol, progesterone, testosterone, triiodothyronine (T3), and thyroxine (T4), were measured from salivary samples collected in late pregnancy. Generalized linear models were used to assess associations between prenatal stress, stress-related hormones, and tooth eruption, adjusting for relevant covariates.
Results
Eruption timing varied within our cohort: 15.2% of children had at least one erupted tooth by 6 months, and 25% had all 20 primary teeth by 24 months. Correlations in tooth counts across visits ranged from 0.15 to 0.57. Several prenatal maternal hormones, including cortisol, estradiol, progesterone, testosterone, and T3, were significantly and positively associated with the number of erupted teeth at individual visits (p < 0.05). Particularly, higher prenatal cortisol levels were associated with more erupted teeth at 6 months, corresponding to an average difference of ∼4 teeth between the lowest and highest cortisol levels.
Conclusion
Maternal salivary hormone levels in late pregnancy may contribute to variations in primary tooth eruption during the first two years of life.
Dental Tribune article – Prenatal stress linked to earlier tooth eruption (Open access)
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