How To Use Ovulation Test Strips

Ovulation test strips, or ovulation predictor kits, are used to determine when a person is ovulating. These tests are helpful for those hoping to become pregnant (or avoid pregnancy) because they're about 99% accurate in identifying a person's fertile window.

While these tests are regarded as the easiest and most trustworthy method to track ovulation, they may not work for everyone.

Read on to learn about how to use ovulation test strips and how they can help track the menstrual cycle.

What Are Ovulation Strips?

Ovulation predictor tests are strips a person pees on to help identify their most fertile time of the month.

An ovulation test kit may come with several paper test strips, or the test may look more like a pregnancy test stick. You either pee on the extended tip of the pregnancy-test-like version, or you pee in a cup and then carefully dip the test strip into your urine.

The tests measure luteinizing hormone (LH) in urine, which is released at low levels throughout the menstrual cycle and surges right before ovulation, explains DeAnna Young, M.D., regional medical director of obstetrics and gynecology with Scripps Coastal Medical Center in San Diego. This increase in LH prompts the ovary to release the egg and ovulate.

People can use ovulation test strips to track their cycle and plan intercourse for the best chances of conceiving. Alternatively, if the user's goal is to avoid pregnancy, they can plan to abstain during that time.

How Ovulation Tests Work

Ovulation predictor kits work by detecting the levels of luteinizing hormone (LH) in the urine. As ovulation approaches, LH spikes to push the egg into the final stages of maturity. This spike of LH is called the LH surge. It happens about 36 hours before ovulation.

The chance of pregnancy is highest when sperm are present in the fallopian tubes at the time of ovulation. So it's ideal to have sex during the 3 to 5 days before ovulation if you're trying to get pregnant (to give the sperm time to travel from the cervix to the fallopian tubes).

Since OPKs detect the LH surge that occurs 12 to 36 hours before ovulation, you'll know when to start having sex at just the right time for conception or when to avoid it.

When Is the Best Time to Use Ovulation Test Strips?

Experts recommend testing for ovulation sometime in the morning, as LH levels are typically highest then.

But Dr. Young warns against testing too early. "I typically recommend using urine from the second morning urination," says Dr. Young. The first trip to the bathroom contains very concentrated urine, which can give a false positive.

Further, Rachel Barr, M.D., a board-certified gynecologist at Maiden Lane Medical in New York City, stresses the importance of reading the instructions on the ovulation test package and notes that some ovulation tests have been calibrated to be taken at the same time each day.

What Does a Positive Ovulation Test Strip Look Like?

Dr. Young notes that "digital tests make it pretty easy to identify when the test is positive," referring to the tests that will indicate a positive or negative result in the display window, such as a happy face or a blank circle. "Non-digital tests will usually show two lines if it is positive and one line if it's negative," she adds.

However, Dr. Barr acknowledges that interpreting the results isn't always as simple as it may seem. She notes that many people will find a faint line even when not ovulating. "LH is present throughout a person's cycle, so most of the time you're going to see a small level of positive," Dr. Barr says.

She recommends taking multiple tests a month to see when the line appears or gets darkest. "In a 30-day cycle, most people will typically ovulate around day 14 to 16," says Dr. Barr. "I typically instruct my patients to start checking every day around day nine or 10 of their cycle—day one being the first day of their period. That way, you're most likely to detect the increase."

What Does a Positive Ovulation Test Strip Mean?

When a test is positive, it usually means that ovulation will occur in approximately 12 to 48 hours. If the user is hoping to conceive, Dr. Barr recommends having sex the day of the positive test and a day afterward.

However, some people have trouble reading a positive ovulation test result. If you don’t get a very strong LH surge, it can be difficult to tell whether the test line is as dark as the control line. Plus, ovulation tests may not work well for people with polycystic ovarian syndrome (PCOS), who can have several LH surges or high levels of LH throughout their cycles.

How Accurate Are Ovulation Test Strips?

When used correctly, ovulation predictor kits are approximately 99% accurate.

However, these tests won't work properly for some people. Here are reasons a person may get a false positive:

• If a user is pregnant or has recently been pregnant since the beta hCG hormone, a hormone the body secretes during pregnancy, is similar to LH
• Users who have reached menopause or are taking fertility drugs containing LH
• Those with polycystic ovary syndrome (PCOS) since they have an increased level of LH all month

How Important Is It To Track Ovulation?

There is only a small window each month in which a person can get pregnant, so if a person wants to conceive through sex, tracking ovulation allows them to identify this window and take full advantage of it.

On the other hand, if users are trying to avoid pregnancy, identifying ovulation and abstaining from sex during that time could be used as a form of birth control.

What Other Ways Can You Track Ovulation?

Ovulation strips are "the easiest and cheapest at-home method" to test ovulation," says Dr. Barr. However, she notes that there are other ways to identify a person's fertile window.

While ovulation predictor kits cannot confirm that ovulation took place, body basal temperature (BBT) charting can. However, unlike charting your BBT, you don’t have to remember to have a thermometer right by your bed or avoid moving too much when you wake up.

One big advantage of ovulation predictor kits, unlike BBT charting, is that they tell you when ovulation is approaching, not that it's already passed. Unless you're also checking your cervical mucus, a BBT chart can’t tell you when you should have sex.

"You can track your cycles with the standard old-school paper and pencil method or you can use one of the many apps that are available now," she says, adding that these methods may involve basal body temperature monitoring and/or documenting symptoms of ovulation such as "feeling cramping or having a change in your cervical mucus."

While perhaps less convenient than the home tests, Dr. Barr adds that progesterone levels can be checked at a doctor's office. A high level of progesterone, she says, is consistent with ovulating.

You can also use an ovulation calculator like the one below.

What To Look For in an Ovulation Predictor Kit

There are plenty of brands and styles of ovulation tests, including ones that test for both LH and estrogen or progesterone. Testing for these other hormones can give users a better idea of when to expect ovulation: When estrogen is detected in urine, it means ovulation is coming up, when progesterone is detected, ovulation has already happened.

However, Dr. Barr recommends keeping it simple when shopping for tests. "Most people will be fine buying the inexpensive dipstick version and not spending a lot of money on the fancier ones," she says. You can buy one at your local drugstore or pharmacy.

The Bottom Line on Ovulation Test Strips

Ovulation tests are helpful for those who are hoping to become pregnant, or hoping to avoid pregnancy, as they can help identify a person's fertile window. These tests should be used for multiple days in a row, during the morning, for the most accurate result. While the tests are generally easy to use, experts acknowledge that they may not work for everyone.