Treatment for two rather than one may help prevent another bout of a common and unpleasant vaginal syndrome.For many women who develop bacterial vaginosis, the syndrome returns weeks or months after treatment. A clinical trial of women in monogamous relationships with male partners found that treating both partners significantly reduced the likelihood of recurrence, researchers report in the March 5 New England Journal of Medicine. When both partners were treated, 35 percent of the women developed bacterial vaginosis again, while in the women-only treatment group, it was 63 percent.The treatment approach builds on past research finding that sexual transmission may account for some repeat episodes of bacterial vaginosis. In the new trial, women received the standard treatment: either an oral antibiotic or an intravaginal antibiotic cream or gel. In the group in which both partners were treated, the male partner took the oral antibiotic and applied an antibiotic cream to the skin of the penis for seven days. In the women-only treatment group, 43 out of 68 developed bacterial vaginosis again within 12 weeks, while only 24 out of 69 did when both partners received treatment.Bacterial vaginosis affects roughly 30 percent of reproductive-aged women worldwide. The syndrome stems from an imbalance in the vaginas microbiota. In a healthy vagina, Lactobacillus bacteria dominate. In bacterial vaginosis, theres a decline in Lactobacillus and an overgrowth of certain pathogenic bacteria. The cause of the imbalance isnt known.One challenge in treating bacterial vaginosis is that its not the same thing in all people, says Caroline Mitchell, director of the Vulvovaginal Disorders Program at Massachusetts General Hospital in Boston. There may be a predominant abundance of a particular pathogenic bacteria or a mix of pathogenic bacteria without a dominant type, she says.Women with bacterial vaginosis can be asymptomatic. Those with symptoms have discharge and vaginal odor. Some women experience irritation, too. Bacterial vaginosis also increases the risk of several gynecological and pregnancy complications, including sexually transmitted infections, pelvic inflammatory disease and preterm birth.Its a big deal, says Mitchell, who was not involved in the trial. People think about this as a nuisance condition it is more than that. It is very disruptive for people.A survey of 62 women whove had recurrent bacterial vaginosis found that the conditionnegatively impacted sexual health for 70 percent, physical health for 68 percent and mental health for 75 percent, researchers reported in 2023 in BMC Womens Health.The syndrome is considered recurrent if it happens three or more times within a year. Its not known why it can be hard to cure bacterial vaginosis. Antibiotic resistance or the development of treatment-hindering biofilms by the pathogenic bacteria are possible explanations. Sexual transmission is another potential contributor. The pathogenic bacteria can reside on the skin of the penis and in the urethra. Past research has found that women with a regular sexual partner were twice as likely to experience recurrence compared with those without.We have so few tools to treat bacterial vaginosis the two classes of antibiotics recommended for treatment have remained the same since 1982, Mitchell says. She sees this new approach as another tool, and while its not relevant for all recurrent cases, I think for some people its going to be a great tool.