Ovulation is the release of an egg from the ovary, when the egg reaches the fallopian tube it is ready to be fertilized. In order for pregnancy to occur the egg must be fertilized by sperm within 24 hours after its release. Immediately prior to ovulation the body produces a surge of Luteinizing hormone (LH) – this usually takes place in the middle of the menstrual cycle. LH triggers the release of the egg from the ovary. Clear & Simple Ovulation tests detect the LH surge in urine, signalling that ovulation is likely to occur in the next 24-48 hours. During this period of ovulation you are at your peak fertility. It is during this most fertile time that pregnancy is most likely to occur if you have sex.
Most people use ovulation tests to track ovulation so that they know when the best time is to try for a baby. Some people use ovulation testing as a natural form of contraception so that they know when to avoid sex. It is not a totally reliable form of contraception but is recommended by some religions opposed to contraception and is sometimes called the rhythm method.
To determine when to start testing you must first determine the length of your Menstrual Cycle. This is the length in number of days from the first day of your period to the last day before your next period starts. Once determined over a number of months refer to the Cycle Chart to the right on which day to start testing.
If you are unsure about your cycle length you may begin the test 11 days after the first day of your period as the average cycle length is 28 days. Perform 1 test each day over a 5 day period or until the LH surge has been detected.
The Clear & Simple ovulation test works by detecting the monthly surge in a key fertility hormone (Luteinising hormone or LH). This hormone is produced 1 to 2 days prior to ovulation so tells you when you are at your most fertile.
If you don’t know your cycle length you are advised to wait for at least one menstrual cycle and note the length of the cycle before using this test. If you want to start without knowing your cycle length you may begin the test 11 days after the first day of your period as the average cycle length is 28 days. Perform 1 test at approximately the same time each day over a 5 day period or until the LH surge has been detected. If your cycle length is irregular and varies by more than 3 days then use the shortest cycle length you have had over the last 6 months to calculate when to test. In both cases it is possible that you either miss your LH surge because you started testing too late or you may need to buy another pack to continue testing after the 5 days because your LH surge was later.
If no lines appear within 10 minutes or if only a test line appears, this is usually due to the strip not being wet enough. Repeat the test ensuring that the strip is immersed in the urine sample for the full 10 seconds.
A positive test result (as in diagram A or B) shows that the LH surge has been detected. Your 2 most fertile days are today and tomorrow so if you have sex in the next 48 hours you will maximise your chance of getting pregnant.
If your result looks like diagram C or D, retest at the same time each day until you detect your LH surge. If your cycle length varies by more than 3 days, it is possible that you will need to start a new pack to detect your LH surge. Some women do not ovulate each cycle and will not have a LH Surge. If you are concerned about your results talk to your doctor.
No, you can stop testing once you have detected your LH surge.
Testing too soon after using fertility drugs that contain HCG (Human Chorionic Gonadotropin) or LH can give misleading results.
If you have recently stopped taking hormonal contraception or are using fertility treatments such as clomiphene citrate, your periods may be irregular leading you to start testing on the wrong day. In this case you may need to use another pack of tests to detect your LH surge.
If you are pregnant or have recently been pregnant (even if not carried to full term) you may get misleading results.
Ectopic pregnancy, ovarian cysts, menopause and some very rare medical conditions may give misleading results.
If you get unexpected results you should talk about them with your doctor.
There are several reasons why you have not become pregnant even though you have been having sex at your most fertile time. In some cases, it can take many months to become pregnant but if you have tried for several months without success you should talk to your doctor.
You may wish to discuss your results with your doctor or call our helpline on: UK 0333 320 2072
Advisors available Mon – Fri 9-5
Call charges vary, please check with your provider. Please be ready to quote the LOT number.
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