"Most commercial lubricants are toxic to sperm, and couples who want fertility should think about carefully choosing the lubricant they want," said study author Dr. William H. Kutteh, a reproductive endocrinologist at the University of Tennessee, in Memphis.

For the study, Kutteh and his team tested four commercially available lubricants against a new "fertility-friendly" lubricant developed by the researchers.

Their lubricant, called ConceivEase, didn't adversely affect sperm motility, Kutteh said, although the other four lubricants did. The new lubricant, with a patent pending, is made by Reproductive Laboratory Inc. in Memphis. Kutteh is an owner of the company and the product is distributed by Sepal Reproductive Devices in Boston, he said.

Kutteh was to present the findings Monday at the American College of Obstetricians and Gynecologists annual meeting, in New Orleans.

The test results could be good news for couples having difficulty conceiving, he said. "People are afraid of going to a fertility doctor because they think they will have to spend $10,000 on IVF [in vitro fertilization]," he said. "Sometimes all you need is a $14.99 oil change."

If sperm aren't moving properly, fertility is affected, Kutteh said. "The sperm have to move through the vagina, through the cervical mucus and out to the fallopian tube. Anything that decreases the motility of the sperm will make the pregnancy rate decline. Sperm can live for 48 to 72 hours."

For the study, five men who had initial sperm counts above 65 percent motility donated sperm. Kutteh's team then exposed the sperm to four commercially available lubricants -- K-Y Jelly, Replens, Touch and Astroglide, along with ConceivEase.

The effects on sperm motility were evaluated at 1 minute, 15 minutes, 30 minutes and one hour. While the ConceivEase maintained sperm motility at 65 percent, the others did not. At one hour, the motility of the sperm exposed to Touch was down to 10 percent, while sperm exposed to the other three lubricants was down to zero, the study found.

Kutteh said he first began noticing the effect of lubricants on sperm more than a decade ago. While at the University of Texas Southwestern Medical Center at Dallas, he published a report in the International Journal of Fertility showing that commercial lubricants were harmful to sperm motility, he said.

Kutteh said he's been giving the lubricant to his own patients for years. Lubricant use during intercourse is common among couples undergoing fertility treatment, he said, partly because ovulation-inducing agents can cause vaginal dryness.

The new lubricant includes light mineral oil, Vitamin E, and glycerol buffered with a certified growth medium. It protects the sperm from pH changes and other factors that can decrease fertility, according to literature from the company.

Dr. Jennifer Wu, an obstetrician-gynecologist at Lenox Hill Hospital in New York City, called the new study interesting, adding that it "holds promise because it doesn't alter sperm motility at one hour."

But, she added, she'd like to see results beyond the one hour, up to 72 hours.

Wu said she typically advises couples trying to conceive not to use commercial lubricants at all, and she thinks that's common advice from doctors. "We don't want to do anything that narrows the window of opportunity for sperm to meet the egg."

And, while the commercially available lubricants were found to kill off sperm, Kutteh added a caveat for those couples not trying to conceive: Don't trust them as contraceptives.

More information

To learn more about infertility, visit the American Society for Reproductive Medicine.