Ovulation predictor kits (OPKs) are a wonderful way of discovering when you are about to ovulate. But, not all doctors and health professionals advocate them. There are many factors that affect the effectiveness of OPKs.
To some women, they are a godsend, helping them to know when to have intercourse or to plan Intrauterine Insemination (IUI). To others, it can be costly and misleading.
The main reason for OPKs is to predict when ovulation should occur within a 12-48 hour time span. An OPK detects a surge of luteinizing hormone – the hormone that prompts the ovaries to release an egg. However, some women may have days of luteinizing surges, and an OPK would continually show a surge. Most kits’ instructions advise to test until you see the first positive surge, then to have intercourse within the next 48 hours. Some women – I am one – will have a surge for 3 full days before actually ovulating. You need to keep these things in mind when using OPKs. Of course, charting is an excellent way of confirming when ovulation has occurred. It may take a month or two to find out how your body does and to correctly use OPKs.
The drawbacks to OPKs are if you are not sure about when ovulation occurs, you are advised to start testing at a certain day in your cycle – for example day 12 – and to test until you see the surge. With me, according to my shortest and longest cycles, I was supposed to start testing on day 10. The first month I tried OPKs I had to buy 2 kits before I finally saw my surge on day 19 and ovulated on day 22. So the guesswork can be very expensive.
Also, the many different brands of OPKs can leave a woman very frustrated. Be sure to read all the instructions. Some brands say that a positive surge is when the result line is as dark as the test line, others say the line has to be darker. OPKs are like pregnancy tests – some can be urinated on directly and others require a cup and dropper. Some kits suggest to use middle-of-the-day urine, while still others require first-morning urine.
If you plan on using an OPK, be sure to follow all instructions and to test at the same time every day. Some practitioners suggest to use an OPK every 12 hours, especially if preparing for intrauterine insemination. This is because of the fact that the egg sometimes only lives as little as 12 hours. Although OPKs are a good way to tell when ovulation occurs, charting all the fertility signs can be as accurate, or more accurate, and saves you money.
Another interesting thing about OPKs is that they can be substituted for home pregnancy tests. While this has not been proven, to my knowledge, I do have a friend who tried this and it indeed worked. It seems the hormones produced in pregnancy are similar to the luteinizing hormone – at least it prompted a positive OPK test result. When I had the chemical pregnancy in August 1999, I tried this with an OPK and had a positive result the same day I had a positive pregnancy test. I suppose in this respect OPKs are cheaper than home pregnancy tests, in that you receive at least 5 tests.
There are also ovulation predictor monitors, also known as Ovacue Fertility Monitors, which can be used indefinitely. They predict and detect luteinizing hormone and rising estrogen. From my understanding, they cost anywhere from about $179 to $300 and you have to buy test strips every month – which costs varies – the one I saw was 30 strips for $50.
Sometimes ovulation does occur on day 14, but this is, by far, not the rule. Because the different elements that bring about ovulation can be varied or interrupted, it’s safe to say that ovulation can occur at any point in the cycle and not the day 14 that so many people once believed.