OPKs and Fertility Monitors

Ovulation Predictor Kits (OPK)/Fertility Monitors

Not sure why they are called kits, as ovulation predictor kits are simply sticks that test urine for the luetinizing hormone (LH). LH is present in the urine right before and up to 48 hours before ovulation occurs. When the control line of an OPK is as dark or darker than the test line, then this is called a peak, and it means you will most likely ovulate in the next 12-48 hours. This is a great way to tell you when you are about to ovulate.

When you need to start testing with OPKs depends on your cycle length. For women with a 28 day cycle, starting to test around day 10 is usually sufficient. For women with a completely typical 28 day cycle where they ovulate on day 14, the ovulation predictor will usually become positive between day 12-13. For those with longer or shorter cycles, count back 18 days from the first day of your expected period and start testing on that day. If your cycles are irregular, error on the side of your shortest cycle. So if they range between 28-30 days, count back from a 28 day cycle. It’s always better to do more tests and have them be negative than to miss your peak!

Couple things to keep in mind:
It is easy to miss your peak/LH surge if you are only testing once a day, especially if your urine is diluted. Most say to test between 10-6 pm. I bought the internet cheapie opks and would test 3 times a day so I was sure not to miss my surge. Some women have lower amounts of LH in and the test doesn't get quite positive. i had read in Consumer Reports that the Clearblue Ovulation Sticks were more sensitive than others. They didn't evaluate the internet cheapies, and I had good luck with those and felt they were pretty sensitive. Clearblue are more expensive but I always had them to confirm the internet cheapies...i just used more of the cheapies because they were much less expensive.
It is possible to have multiple peak days. Usually you will have 1 or 2 days of positive OPKs. Because I was testing 3 times a day, I would often have 3 days. This means I was catching the very beginning of my surge and the very end of my surge. If ovulation was delayed for any reason, it is also possible to have multiple days.

Fertility monitors are similar in that they tell you ahead of time when you are possibly going to ovulate. The monitors check for other hormones and can sometimes tell you much sooner than only checking for LH. I used the Clearblue Fertility Monitor and liked it. I'm not sure how much it helped, but it was accurate for my ovulation days and I know people who used it and felt it was what truly helped them get pregnant.

It is important to know that a positive ovulation test does not confirm that you will ovulate. It is a good indicator, but it is possible to have a positive ovulation stick and then for some reason have a delayed ovulation, or not ovulate at all. Women who suffer from polycystic ovarian syndrome (pcos) may have inaccurate results with an opk. Women with pcos tend to have LH surges more often during their cycle and an egg is not always released, leading to multiple positive OPKs without ovulation. Some women with PCOS have reported good results using Vitex.