• Decrease font size
  • Return font size to normal
  • Increase font size
U.S. Department of Health and Human Services

Medical Devices

  • Print
  • Share
  • E-mail

Ovulation (Saliva Test)

What does this test do? This is a home-use test kit to predict ovulation by looking at patterns formed by your saliva. When your estrogen increases near your time of ovulation, your dried saliva may form a fern-shaped pattern.

What type of test is this? This is a qualitative test -- you find out whether or not you may be near your ovulation time, not if you will definitely become pregnant.

Why should you do this test? You should do this test if you want to know when you expect to ovulate and be in the most fertile part of your menstrual cycle. This test can be used to help you plan to become pregnant. You should not use this test to help prevent pregnancy, because it is not reliable for that purpose.

How accurate is this test? This test may not work well for you. Some of the reasons are

  • not all women fern
  • you may not be able to see the fern
  • women who fern on some days of their fertile period, don't necessarily fern on all of their fertile days
  • ferning may be disrupted by
    • smoking
    • eating
    • drinking
    • brushing your teeth
    • how you put your saliva on the slide
    • where you were when you did the test

How do you do this test? In this test, you get a small microscope with built-in or removable slides. You put some of your saliva on a glass slide, allow it to dry, and look at the pattern it makes. You will see dots and circles, a fern (full or partial), or a combination depending on where you are in your monthly cycle.

You will get your best results when you use the test within the 5-day period around your expected ovulation. This period includes the 2 days before and the 2 days after your expected day of ovulation. The test is not perfect, though, and you might fern outside of this time period or when you are pregnant. Even some men will fern.

Is this test similar to the one my doctor uses? The fertility tests your doctor uses are automated, and they may give more consistent results. Your doctor may use other tests that are not yet available for home use (i.e., blood and urine laboratory tests) and information about your history to get a better view of your fertility status.

Does a positive test mean you are ovulating? A positive test indicates that you may be near ovulation. It does not mean that you will definitely become pregnant.

Do negative test results mean that you are not ovulating? No, there may be many reasons why you did not detect your time of ovulation. You should not use this test to help prevent pregnancy, because it is not reliable for that purpose.