LH (Luteinizing Hormone) is one of the hormones produced by the pituitary gland. It is secreted at very low levels throughout your menstrual cycle. Once a developing egg follicle reaches a certain size, LH secretion surges to high levels. This hormone surge is what triggers ovulation about 24 to 48 hours later. Your LH surge is important because it initiates the beginning of ovulation. Ovulation is the release of a mature egg from the ovary. It signals the beginning of your fertile period. A positive result indicates the presence of a high amount of LH or LH surge.
The amount of LH in your body will begin to decrease after ovulation, so you’ll only get a positive result during that crucial fertile period. Once the egg is released, it is only viable for about 24 hours. After that, your fertile window is over. This makes it very important to be able to identify this best time to conceive.
Ovulation may be irregular because of conditions, emotions and other factors in your life. You can’t presume that ovulation always occurs at the same time after menstruation. Therefore, you should test again in each menstrual cycle.
The length of the menstrual cycle is the duration from your first menstrual bleeding day to the day before the next bleeding begins. Determine the length of menstrual cycle before test. Please refer to the chart below to determine when you should start testing. If your cycle is shorter than 21 days or longer than 38 days, consult a physician. If you do not know your cycle length, you may begin the test 11 days after your first period since the average cycle length is 28 days.
When to collect urine for the test? Any urine specimen is appropriate for ovulation testing. The ideal time for ovulation test is in the afternoon, though testing may take place from 10am to early evening.
How long should I continue to perform the test?
At least 5 days or until the LH surge has been detected.
Once I see a positive result, when is the best time to have intercourse? Ovulation is likely to occur within 24-48 hours. This is the most fertile time. Sexual intercourse is advised within this time frame.
I have received a positive result and had intercourse during these fertile days. I have not become pregnant. What shall I do? Many factors can affect your ability to become pregnant. Often you may need to use the test kit for 3-4 months. You and your partner should consult your physician if pregnancy is not achieved after 3-4 months.
Will the amount of liquid I drink affect the result? We suggest that you limit your fluid intake for about two hours before you collect your urine. Because heavy intake of fluids prior to testing will dilute the hormone in your urine.
Can test results be interpreted after more than 5 minutes? No. Test results must be read at 5 minutes. Though a positive result should not change for several days, a negative result may change to a false positive within minutes after the end of the testing period, which would not be an accurate reading. It is always best to read the results at the 5 minute testing period and then discard the test to avoid confusion.
Can any medication or medical condition affect the result? Certain medical conditions and medications can adversely affect the performance of the test: for example if you are actually pregnant, have recently been pregnant, have reached menopause or have polycystic ovarian syndrome you may get a misleading result. This may also be true if you are taking fertility drugs containing Luteinizing Hormone or Human Chorionic Gonadotrophin (such as Pregnyl® and Profasi®). Clomiphene citrate (Clomid®) does not affect the tests, but may affect the length of your cycle and, therefore, when you should be testing.