For women, a bigger brood brings a bigger risk of dental problems, new research reports.

The study found that U.S. women who had more children were more likely to have periodontal disease, more missing teeth and more untreated cavities.

In an interview, study author Dr. Stefanie Russell of New York University in New York explained that these findings persisted even when she factored in the influence of mothers’ social class, income, education and age.

Russell suggested that pregnancy may have a biological effect on oral health, making women prone to dental difficulties. “It’s possible that women who have multiple pregnancies could have lasting effects” regarding their oral health, she told Reuters Health.

Women with many children are also often forced to lead “different lives” from other women, she added. A big and busy household is stressful, and may leave mothers with less time to take care of themselves by visiting the dentist, Russell suggested. Women who are busier may also have less energy to put into eating well or quitting smoking, the researcher said.

An alternative explanation for why having children may take a toll on women’s oral health is that dentists are often “very conservative” when treating pregnant women, Russell said. Many dentists worry about what X-rays and anesthesia could do to unborn children, she said, and may consequently ask women to postpone treatment for dental problems until after childbirth.

However, as every parent knows, newborns are very time-consuming, and new mothers may simply feel they can’t squeeze in a dentist appointment to deal with an earlier problem, Russell noted.

All of these factors likely contribute to mothers’ poor oral health, she added. “I think it’s multiple causes.”

To investigate how a bigger brood influences oral health, Russell reviewed data collected from 2,635 women between the ages of 18 and 64 who had been pregnant at least once.

She reported her findings last week during the 83rd General Session of the International Association for Dental Research in Baltimore.

Russell noted that these findings suggest that women need to make sure they take good care of their teeth after having children. But it’s not just their responsibility, she said. As a society, we need to provide mothers with more support, so that they have time to go to the dentist, Russell declared.