Women who suffer from frequent vaginal yeast infections show biochemical signs of being under chronic stress, a Swedish study has found.

Dr. Sophia M. Ehrstrom, of the Karolinska Institute, Stockholm, and colleagues, reporting in the American Journal of Obstetrics and Gynecology, note that the problem of recurrent yeast infections is on the rise.

To investigate any link to stress, the researchers studied 35 women who experienced at least four yeast infections during the preceding year and 35 healthy "controls."

The team collected saliva samples from the participants in order to measure levels of the stress hormone cortisol.

Cortisol levels usually rise in the morning, but Ehrstrom's team found that this rise was blunted among the patients with recurrent yeast infections compared with the control subjects.

A shallow rise in cortisol, somewhat paradoxically, indicates a state of ongoing stress, according to the researchers.

They also found that more patients than controls had a history of other vaginal infections, supporting "the hypothesis of a reduced local immunity" in women with recurrent yeast infections.

The authors conclude that "chronic stress may play a role" in the occurrence of frequent yeast infections, and "further studies are needed to elucidate the connection between" all their findings."

SOURCE: American Journal of Obstetrics and Gynecology, October 2005.