Pubic hair grooming is linked to a heightened risk of acquiring a sexually transmitted infection, finds research published online in the journal Sexually Transmitted Infections.

The association seems to be strongest among those who groom their pubic hair frequently and intensively—a practice dubbed 'extreme grooming' by the researchers—the findings show.

Pubic hair removal is becoming increasingly common among men and women worldwide amid changing perceptions of the role of body hair in attractiveness, cleanliness, and feelings of masculinity/femininity, say the researchers.

To find out what impact this growing trend might be having on rates of , the researchers polled a nationally representative random sample of US adults about their intimate grooming habits.

Among the 14,000+ sample of 18-65 year olds, some 7580 (56% men) completed the survey, responding to questions about the intensity (trimming or complete removal) and frequency (from daily to annually) of their public hair grooming, as well as the tools they typically used.

'Extreme' groomers were classified as those who removed all their public hair more than 11 times a year, and 'high frequency' groomers as those who trimmed their pubic hair daily or weekly.

Participants were also asked about their sexual history. Some 7470 said they had had at least one sexual partner.

Almost three out of four (74%) respondents said they had groomed their pubic hair before, with more women (84%) than men (66%), saying they had done so.

Among the groomers, 17% were classified as 'extreme' and 22% as 'high frequency', with one in 10 falling into both categories.

Overall, groomers tended to be younger, more sexually active, and to have had more annual and total lifetime sexual partners than those who said they didn't groom their pubic hair.

And the number of sexual partners among extreme groomers was higher than it was for any other category of groomer.

An electric razor was the most common grooming tool among men (42%), while a manual razor was more common among women (61%). Around one in five men and women used scissors.

In all, 13% (943) respondents said they had had at least one of the following: herpes; (HPV); syphilis; molluscum; gonorrhoea; chlamydia; HIV; or pubic lice.

After factoring in age and the number of lifetime , any type of grooming was associated with an 80% heightened risk of having a sexually transmitted infection compared with no grooming.

Intensity and frequency of grooming also seemed to be linked to the magnitude of risk. Among and extreme groomers, the practice was associated with a 3.5 to 4-fold heightened risk, particularly for infections that arise through skin on skin contact, such as herpes and HPV.

By contrast, low intensity/frequency grooming was associated with a doubling in risk of a lice infestation, suggesting that grooming might make it harder for lice to breed successfully.

This is an observational study, so no firm conclusions can be drawn about cause and effect, added to which the researchers were not able to determine the timing of grooming relative to acquisition of infection, or account for either safer sex practices or indeed risky sexual behaviours.

To explain their findings, the researchers suggest that grooming might be a proxy for higher levels of sexual activity and associated infection risk, or that it might cause tiny skin tears, through which bacteria and viruses can easily pass.

Further research is needed to shed some light on these possibilities, say the researchers. Either way, evidence of could be a useful prompt for clinicians to ask about safer sex practices, or to suggest delaying sex to allow the skin to heal, they add.

More information: Correlation between pubic hair grooming and STIs: results from a nationally representative probability sample, sti.bmj.com/lookup/doi/10.1136 … sextrans-2016-052687

Journal information: Sexually Transmitted Infections