Scientific studies over the past two decades have shown that home urine luteinizing hormone tests are reliable indicators of ovulation. A landmark study from 1990 published in the Medical Journal of Australia compared the results of urine LH tests with daily LH measurements taken from the blood. The urine LH test was found to be more accurate than both cervical scoring and basal body temperature (BBT) at predicting ovulation.
Another study six years later in Obstetrics and Gynecology compared urine LH tests with the gold standard for determining ovulation, transvaginal ultrasound. The urine LH tests reliably predicted ovulation within 48 hours of the egg being released from the ovary, as seen on ultrasound.
A further study in 1999 in Fertility and Sterility compared urine LH tests, cervical mucus and salivary ferning with transvaginal ultrasound. Self-assessment of cervical mucus correlated less than 50 percent of the time with ovulation, while salivary ferning correlated less than 40 percent. By comparison, the urine LH tests correlated 100 percent with ovulation as seen by ultrasound.
Similar to pregnancy tests in design, urine LH tests work by wicking urine up a test strip to the testing areas. One line shows that the test is working correctly, and another line appears shows whether LH is present. When the second line is as dark as or darker than the control line, a woman's LH surge has arrived, and she will be ovulating within the next day. Having unprotected intercourse during the next 48 hours can maximize her chances of becoming pregnant.
All of this leads to a question: Which is the best urine LH test to use? The most tested and recommended in scientific studies is the Clearblue Easy Ovulation Test (*Est. $21 for 7 tests). The urine LH test used in the Medical Journal of Australia study mentioned previously was the Clearblue Easy Ovulation Test. A study in 2001 published in Obstetrics and Gynecology compared BBT with the Clearblue Easy Ovulation Test using transvaginal ultrasound to verify ovulation. In 100 percent of the cases, the LH peak as detected by the Clearblue test occurred within the three days prior to ovulation, whereas BBT was a poor indicator of ovulation. One consumer test cited often in the major scientific reviews compared various urine LH tests on their sensitivity to LH. The Clearblue Easy Ovulation Test was determined to be the easiest to read and the most sensitive at 22 milli-International Units (mIU) per milliliter (ml).
This brings up an important limitation with the Clearblue Easy Ovulation Test and all urine LH tests: Each has a minimum threshold of LH that must be met to give a positive reading. While most women peak between 20 mIU/ml and 100 mIU/ml of LH, there will be some women whose surges are not detected. So even though the Clearblue Easy Ovulation Test can detect LH levels as low as 22 mIU/ml, it will still miss the 12 percent of women's surges that fall below that threshold.
But it isn't just the scientific community who find the Clearblue Easy Ovulation Test reliable. Most consumers give it glowing reviews. At Amazon.com, Drugstore.com and Diapers.com, women say that the Clearblue Easy Ovulation Test was easy to use and helped them to conceive right away. However, some users found it difficult to determine if the test line was as dark as the control line -- a common complaint with all urine LH tests, not just with Clearblue. As a result, Clearblue offers a digital version of their ovulation test. Instead of trying to determine which line is darker, you feed the test strip into a test holder and it reads the test for you. If it detects a surge in your LH, a little smiley face appears on the display window. The Clearblue Easy Digital Ovulation Test (*Est. $35 for 20 tests) receives reviews that are as good as its nondigital counterpart, and it is the second most recommended urine LH test on the market. On Amazon.com, about 200 consumers give the Clearblue Easy Digital Ovulation Test more than 4 out of a possible 5 stars. Some reviewers say it's worth the extra money to alleviate the anxiety of trying to read the test themselves. Because the digital version of the Clearblue Easy Ovulation test is easy to read, we decided it should receive the distinction of Best Reviewed Ovulation Test Strips.
With both these Clearblue ovulation tests -- and all urine LH tests -- there are some important drawbacks. If a woman's menstrual cycle is very short, very long or irregular, she may have difficulty determining the best day to begin testing. As mentioned previously, women vary as to when they ovulate, and if a woman happens to ovulate later in her cycle, she may be going through 10 or more tests each month. The cost can quickly add up, so users may want to buy in bulk.
Though there aren't many reviews out there, Early-Pregnancy-Tests.com Ovulation Test Strips (*Est. $18 for 20 tests) receive good feedback from consumers at Amazon.com and AssociatedContent.com. Early-Pregnacy-Tests.com offers bulk discounts on their tests, with the price per unit dropping as quantity you order increases. The tests are approved by the Food and Drug Administration (FDA), and most reviewers say they work as well as the leading store brands. Though, some users report that they got inconsistent and inaccurate results.
Finally, some women cannot use urine LH tests. If a woman is on fertility medications, has polycystic ovarian syndrome (PCOS), is already pregnant or is in menopause, she can get false positive results. In addition, any health conditions, such as thyroid disorders or medications that affect her hormones can alter the test results. Of note, Clomid, also known as clomiphene citrate, may interfere with the test. If a woman is using this medication, she should consult with her doctor before using the test.
While the Clearblue Easy Ovulation Test (*Est. $21 for 7 tests) has received excellent reviews, the best ovulation predictor or fertility device is another one of the company's products: the Clearblue Easy Fertility Monitor (*Est. $170); replacement test strips cost about $38 for 30 test sticks. Urine luteinizing hormone (LH) tests predict the two most fertile days for a woman each cycle, but the Clearblue Easy Fertility Monitor can predict up to six fertile days. The difference is that the Clearblue Monitor tests not only for LH, but also for estrone-3-glucuronide (E3G). For the first month, a woman tests for 20 days to create a baseline for her cycle. The battery-operated monitor then tells her when to test over the next month, often 10 to 20 days, and informs her if she's at low, high or peak fertility.
Multiple scientific studies have demonstrated the reliability and effectiveness of the Clearblue Easy Fertility Monitor. A study published in 2000 in Human Reproduction compared its reliability with transvaginal ultrasound. Researchers found that during the two peak fertility days listed by the monitor, ovulation, as seen by ultrasound, occurred 91.1 percent of the time. Importantly, peak fertility was never indicated after ovulation had occurred.
A further study, published in Fertility and Sterility in 2007, tested the monitor's efficacy at helping couples to conceive. More than 300 women were provided with the Clearblue Easy Fertility Monitor, while another 300 women did not and acted as a control group. The couples were given no help or direction besides the manufacturer's instructions. The couples that used the monitor had a pregnancy rate of 22.7 percent during the first two menstrual cycles, while the control group's pregnancy rate was only 14.4 percent. That's an increased chance of pregnancy of more than 50 percent.
Beyond the scientific and medical community, the Clearblue Easy Fertility Monitor is one of the most popular fertility devices. Consumer testing found it to be one of the most sensitive tests to LH, second only to the Clearblue Easy Ovulation Test. JustMommies.com chooses it as one of the best fertility gadgets, and About.com's pregnancy guide, Robin Elise Weiss, gives it 4.5 stars out of a possible 5. Though Weiss finds the Clearblue Monitor accurate and easy to use, she notes that the greatest drawback is the high price of the monitor and test strips.
The Clearblue Easy Fertility Monitor costs $170, with test strips running about $38 for 30, plus the cost of the four AA batteries required to power it. In comparison, the Clearblue Easy Ovulation Test strips run about $21 for seven strips. Numerous reviewers at Amazon.com, Drugstore.com and Diapers.com, however, say that the Clearblue Easy Fertility Monitor is well worth the price. They found it easy to use and easy to read, and many say they conceived within the first few cycles of use.
As with the urine LH tests, the Clearblue Easy Fertility Monitor has its limitations. If you have an irregular menstrual cycle, you may have to use closer to 20 test sticks each month, effectively doubling your cost. If your menstrual cycle is less than 21 days or more than 42 days, it will not work for you. Polycystic ovarian syndrome (PCOS), impaired liver or kidney function, pregnancy and menopause can alter the results. In addition, fertility medications and any health conditions or medications that affect your hormones can change the test results. As always, if you have any health conditions or are on any medications, consult with your physician before using this or any other fertility device.