Female condoms may be more prone to slipping or other technical difficulties than male versions are, but the two seem similarly effective at blocking semen, research suggests.

In a study of women who were given male condoms and female condoms to use during sex, researchers found that “mechanical problems” were four times as frequent with the female condoms as with the male versions.

Yet the women were about as likely to be exposed to semen when using female condoms as they were when using male condoms, according to findings published in the American Journal of Epidemiology.

Semen exposure offers a way of measuring a condom’s likelihood of protecting against sexually transmitted diseases (STDs) and pregnancy. So the current findings suggest that male and female condoms provide comparable protection, according to the researchers, led by Dr. Maurizio Macaluso of the U.S. Centers for Disease Control and Prevention in Atlanta.

The study involved 108 women who were given 10 male condoms and 10 female condoms; some were asked to use their male condoms first then switch, while the rest were asked to start with the female version. All of the women received instruction on how to properly use both types of condom.

The study participants were also given swabs to take samples of their vaginal fluid before and after having sex. The researchers then tested these samples for prostate-specific antigen (PSA), a protein found in semen.

Overall, Macaluso’s team found, the women had some type of mechanical problem with the female condoms one-third of the time, versus only 9 percent of the time with the male condoms.

One of the most common problems with the female condoms was that they tended to slip out. Other issues included “penis misrouting” around the side of the condom. However, there were only two reports of the female condom breaking.

Mechanical problems with male condoms were generally less common, but women frequently said that their partner used the condom incorrectly.

In the end, the study found, women’s semen exposure was comparable whether they used the male or female condom. Moderate-high levels of PSA were detected in 3.5 percent of male condom uses and 4.5 percent of female condom uses.

This minor difference, according to the researchers, suggests that while female condoms present certain mechanical problems, they are similar to the male version in protecting against STDs and pregnancy.

SOURCE: American Journal of Epidemiology, July 1, 2007.