Women with caries who deliver babies by cesarean section should pay special attention to their newborns’ oral health, according to a study published in the September issue of Journal of Dental Research.
Researchers at New York University conducted a four-year study of 156 mother-infant pairs; 127 women had vaginal delivery and 29 had cesarean delivery. The women were predominantly African-American, from an inner-city area of Birmingham, Ala., and included in the study beginning in their third trimester of pregnancy.
Women in the study who had cesarean delivery had high levels of Streptococcus mutans infection, as well as caries on an average of one-third of their teeth. A majority of these women had an annual family income of $10,000 or less—a potential barrier to accessing dental care—and a history of sexually transmitted disease.
The study’s principal investigator, Dr. Yihong Li, associate professor, Basic Science and Craniofacial Biology, NYU College of Dentistry, and colleagues from NYU and University of Alabama at Birmingham found that babies delivered by cesarean section were infected by S. mutans almost a year earlier than were infants delivered vaginally. The first signs of the bacterium appeared at an average of 17.1 months of age in babies delivered by cesarean section, compared with 28.8 months in infants delivered vaginally. Researchers said this was a significant finding, since previous studies have linked earlier bacterial infection with a higher rate of dental caries in children.
"Vaginally delivered infants offer oral bacteria a less hospitable environment," said Dr. Li. "They develop more resistance to these bacteria in their first year of life, in part because of exposure to a greater variety and intensity of bacteria from their mothers and the surrounding environment at birth. C-section babies have less bacterial exposure at birth, and therefore less resistance."
The findings suggest that mothers who have dental caries should inform their dentists if they have cesarean delivery because of the potentially higher risk that the child also will develop caries, said Dr. Li.
Researchers say further study is needed to determine if cesarean births can be linked to earlier acquisition of S. mutans and other oral bacteria in a broader cross-section of the population, and if a higher incidence of caries follows.
