Clear Blue Digital Ovulation Tests Kit helps you maximise your chances of conceiving naturally by identifying your 2 most fertile days each cycle by measuring the changes in level of a key fertility hormone – luteinising hormone (LH). It's more accurate than calendar and temperature methods and gives you unmistakably clear results on a digital display. In every cycle there are only a few days when a woman can conceive, so having sex on these days is very important if you are trying to get pregnant. The number of Test Sticks in a Clearblue Digital Ovulation Test pack is sufficient for most women with regular cycles to detect their LH surge. If your cycle length varies by more than 3 days then it is possible that you may need to start a new pack to detect your LH surge. Ovulation is spontaneously triggered about 24-36 hours after blood levels of a hormone called luteinizing hormone (LH) rise. This is called the LH surge. Once released from the ovary, the egg is picked up by and travels down the fallopian tube where it can meet sperm to become fertilized. Certain medical conditions and medications can adversely affect the performance of the test: for example if you are actually pregnant, have recently been pregnant, have reached the menopause or have polycystic ovarian syndrome, taking fertility drugs which leads to a misleading result. All Clearblue tests are designed with women in mind, and include unique and innovative features to make them easy to use and easy to read, so you can be confident in your result, helping reassure you when you need it most. Clearblue has been a pioneer in pregnancy testing for over 30 years, delivering new and innovative products.