WASHINGTON (AP) _ Women wishing to become pregnant are about to get a new way to predict when they are fertile: The government has approved the sale of the nation's first saliva ovulation test.
Women's estrogen levels gradually rise each month, peaking with ovulation, the time each month that they can conceive.
A woman can predict ovulation by measuring her body temperature's rise with estrogen's rise, undergoing a blood test to check hormone levels, or _ more common _ using a urine test that detects a surge in an estrogen-related hormone 24 to 36 hours before ovulation.
The new TCI Ovulation Tester is a reliable alternative that women may find less messy to use, Food and Drug Administration reviewer Veronica Calvin said Friday.
Roughly 50 years ago, scientists realized that as estrogen surges, the salt content of saliva increases, too, Calvin explained. When the saliva of an about-to-ovulate woman dries, the salt leaves a crystal pattern called ferning _ it actually looks like a fern plant _ that can be seen under a microscope.
The new test is a round device that pairs tiny slides with a handheld microscope.
Touch a little brush to saliva in your mouth, then dab it onto one of the slides. Let it dry and look through the eyepiece. If there's only a little of the salt _ potassium chloride _ seen as little dots, then ovulation isn't near yet. Test the next day and you may see the dots starting to form chains. Once a true fern pattern appears, ovulation is imminent.
In studies comparing the saliva test to urine tests, the TCI Ovulation Tester proved more than 90 percent reliable in indicating ovulation, Calvin said.
In fact, ``one of the things that's interesting about this test is you may be actually getting a little bit of warning that you're getting close to ovulation'' by watching the pattern gradually appear, said FDA medical device chief Dr. David Feigal.
With urine tests, in contrast, women have a chance of missing ovulation depending on when they test, because the results are given as a simple yes or no instead of suggesting whether hormones are increasing, he said.
Manufacturer TCI Optics said it will begin selling the nonprescription test, for $59.95, in a few weeks. Sales will begin via the company's Internet site _ www.ovulationtester.com _ or by telephone at 1-866-OVULATION. But the company is negotiating with larger medical firms in hopes of beginning drugstore sales as well, a spokesman said.