Approximately 100 million women worldwide who use birth control pills as contraceptives may be putting themselves at risk for having their long-term sexual drive decrease, according to a study released in January.

The study, featured in the January issue of The Journal of Sexual Medicine, finds that oral contraceptive may negatively affect female sexual hormones.

The study found that women taking the pill had four times the amount of a sex hormone that decreases testosterone than women who are not on the pill, which may be linked to a decreased sex drive, according to the research conducted by Dr. Claudia Panzer, Dr. Irwin Goldstein and colleagues from the Boston University Medical Center.

Researchers also found that women, even six months after they had stopped using the pill, still had higher hormonal levels than women who had never taken the pill, suggesting that oral contraceptives may have lasting effects.

Panzer said, in her study, she believes a woman’s testosterone level greatly affects her sex drive.

“Lowered levels of … free testosterone were believed to play a major role in women’s sexual health that could place women at risk for decreased sexual desire, arousal, decreased lubrication and increased sexual pain,” she said.

Dr. Jennifer Bass, spokeswoman for the Kinsey Institute, a research center for sex, gender and reproduction, said researchers at the Institute challenge the study’s claim that oral contraceptives may have permanent effects on a woman’s sex drive.

“In our research we support the idea that some women are less interested in sex as a side effect of the pill, but we don’t see any changes in the production of hormones in a permanent way,” Bass said.

Bass added that while the pill can lower a woman’s libido, the effects will go away once the patient switches to different hormones.

“It’s all very unclear because it is difficult to say that a particular hormone is directly related to sexual desire,” she continued. “There is no direct cause and effect that we know of.”

Dr. Marcie Richardson, an obstetrician-gynecologist and co-director of the Menopause Consultation Service also said she is also skeptical of the controversial study.

But Richardson did say she does not dispute that oral contraceptives increase testosterone levels.

“There are doctors that speculate that this may explain the reduced libido that women experience in birth control pills,” she said.

Still, Richardson added that a study in the Journal of Medical Society showed that testosterone levels do not always correlate with a woman’s sexual desire or satisfaction.

“[The ambiguity of research] is the difficult area about this,” Richardson said. “For women, the most important sex organ is the brain. It is very difficult to study sexuality at all in women and have it be clean data.”

Since the birth control pill’s advent in 1960, countless tests have been conducted to determine the pill’s side effects, Richardson said. However, female sexuality hasn’t been on the radar screen until recently.

“Female sexuality is very hard to study,” Richardson said. “You can give women a diary and ask if or whether they had orgasms, but there are several variables.”

Such variables, pointed out by both Richardson and Bass, include the type of relationship a woman is in and her emotions and psychological effects that sexual intercourse may have.

Panzer also noted in the journal that the most important aspect of testing the birth control pill involves informing patients of all side effects.

“It is important for physicians prescribing oral contraceptives to point out to their patients potential sexual side effects,” Panzer wrote. “Also if women present these complaints, it is crucial to recognize the link between sexual dysfunction and the oral contraceptive and not to attribute these complaints solely to psychological causes.”

College of Communication sophomore Sara Jacobi said she also thinks it is imperative for doctors to mention decreased sex drive as a potential side effect before prescribing the pill.

“It is important to know that loss of sexual desire is a possible side effect of taking birth control because there are so many other factors,” she said.