NEW YORK (Reuters Health) - Pregnant women can be reassured that cleaning with a bidet after using the toilet will not throw off their vaginal bacteria balance or increase the risk their baby will be born early, a new study suggests.
One cause of premature birth is inflammation around the fetus, which can stem from a vaginal infection. Researchers have been unsure whether various forms of genital washing, including bidet use and douching, might clear out healthy bacteria and increase the risk of vaginosis, or vaginal bacterial infections.
The new findings are "reassuring," according to Dr. John Thorp, an obstetrician-gynecologist at the University of North Carolina at Chapel Hill, who has studied prevention of premature birth.
"This is an important study given the common practice of bidet use outside the U.S. and the potential harms (that) alterations in the vaginal microflora might have on the risk of preterm birth," Thorp, who was not involved in the new research, told Reuters Health in an email.
In Japan, according to the study authors, 72 percent of households have electric bidets installed. Modern models are typically incorporated into standard toilets, rather than separate fixtures.
For the new study, the researchers led by Dr. Keiko Asakura from the Keio University School of Medicine in Tokyo surveyed 1,300 women who had a baby between 2006 and 2010 about their past bidet use. About 63 percent of them reported using a bidet shortly before and during pregnancy.
Regardless of whether they had used a bidet, 16 percent of women gave birth prematurely - defined as before 37 weeks. That proportion is higher than average, the researchers noted, because their hospital is known for treating infertility and pregnancy problems.
A similar proportion of bidet and non-bidet users - 20.3 percent and 20.7 percent, respectively - also tested positive for bacterial vaginosis, according to samples taken at their prenatal exams, the study team wrote in Obstetrics & Gynecology.
Thorp said women and their doctors now have evidence that can help them make decisions about bidet use in pregnancy. Some of his own work has tied douching before pregnancy to a higher risk of premature birth - but douching may be more internal than bidet baths, he noted.
Asakura's team said it would be useful going forward to see if bidet use does affect outcomes for women with compromised immune systems, for example.
But for now, the researchers wrote, it seems safe.
"Normal use of the bidet toilet by pregnant women poses no clinical health risk for preterm birth and bacterial vaginosis," they concluded.