Common ovulation predictors include:
Ovulation Predictor Kits allow you to see when you are about to ovulate by measuring the presence of LH (Luteinizing Hormone) in your urine. Since LH is the hormone responsible for triggering the release of egg from the ovary, a LH surge indicates that you are about to ovulate.
When you should start testing depends on your menstrual cycle length. The shorter the cycle, the earlier you should start testing. The general rule of thumb is that you want to test 17 days before your next period is due. So, for example, if you are on a 28-day cycle, you'll want to start testing 11 days after your period.
There are two main methods of doing a urine test. The first is using single-use test strips such as ClearBlue Easy Ovulation Test. The second is using a fertility monitor in addition to the test strip. The advantage of using the fertility monitor is that it automatically keeps track of all your history, and will tell you when you need to start testing. On the other hand, if you have very irregular or unusually long cycles, you should not use the fertility monitor.
A fertility watch monitors your chlorine ion levels while you sleep, and can alert you 4 days before ovulation. The advantage of using a fertility watch is that it is very easy to do: Just remember to wear the watch before you go to sleep.