Ovulation Predictor Kit
An ovulation predictor kit (OPK) is a home fertility test which indicates when you are ovulating. The test is designed to detect a surge in the hormone called LH (luteinizing hormone). Levels of this hormone rise just before the point in each menstrual cycle at which the ovaries release an egg. After this happens, you have a 2 to 3-day fertile window in which you have a chance of getting pregnant.
Where To Buy OPKs
You don't need a prescription from a doctor to purchase an OPK. They are available at grocery stores, pharmacies and online. Sometimes ordering via the internet is the cheapest option. In each kit there are approximately 5 to 9 tests, although this varies from manufacturer to manufacturer. Typical prices per individual test range from $3 to $7, whereas prices per kit vary from $20 to $70.
How To Use OPKs
An OPK is a urine testing kit, similar to a pregnancy test. You should always read the manufacturer's instructions and follow them to the letter.
The manufacturer will probably advise that you pee directly onto the strip protruding from the end of the test device, or into a sterile cup. If you use a cup then you'll have to dip the strip into the urine for 15 to 20 seconds.
The test will then indicate whether you have a positive or negative reading for the LH surge. If you have a positive reading, you know that ovulation is likely to take place within the next 24 hours. You now have a window of 2 to 3 days in which unprotected sexual intercourse is more likely to result in pregnancy.
When To Use OPKs
In a typical menstrual cycle, ovulation occurs at about the half-way mark. So if your menstrual cycle lasts 28 days, then ovulation may occur on or around day 14. In this case, your OPK manufacturer will probably recommend that you begin testing on day 11, and continue to test daily for a few days. The manufacturer's instructions always take precedence over any information written here. Often the manufacturer takes into account the fact that women's cycles vary - they may provide instructions for what to do if your cycle is shorter or longer than average.
A Few Cautionary Words
Not everyone is convinced of the usefulness of OPKs, and even the manufacturers admit that that for some women, this type of fertility test is not helpful. Such women include:
- Women with very irregular cycles - such women would use a very large number of tests throughout the month and would therefore spend a lot more money than women with predictable menstrual cycles.
- PCOS patients - women who are affected by polycystic ovarian syndrome may have elevated levels of LH generally, which can produce false positive readings on an OPK.
- Women who are taking fertility drugs - some fertility medications can interfere with the results of an OPK. If you are taking these drugs you should consult your fertility doctor about how to use the OPK, and follow the manufacturer's instructions carefully. In the case of discrepancy between what the manufacturer says and what your doctor recommends, we advise you to always follow your doctor's advice.