Urine-Based Fertility Monitors
Urine-based fertility monitors work by detecting the levels of key hormones present in urine which can indicate ovulation. The most popular urine-based fertility monitor, the ClearPlan Easy Fertility Monitor, works by tracking the LH (Luteinizing Hormone) and Estrogen levels in urine through the use of fertility monitor test sticks.
Based on the start of the menstrual cycle, the monitor "asks" you to perform a test stick reading for 10 or 20 consecutive days depending on the length of your cycle and the timing of your Luteinizing Hormone (LH) surge.
The test sticks are read by the monitor which then informs you of your fertility level - Low, High, or Peak. Intercourse during High and Peak fertility days help to maximize chances of becoming pregnant. The monitor identifies 6 days (on average) of fertility. Most women will get 1-5 days of "High Level" readings before arriving at their 2 "Peak Level" days of fertility.
Examples: ClearPlan Easy Fertility Monitor
Advantages: Removes much of the "user interpretation errors" that can accompany saliva-based ovulation prediction methods. Very little learning curve.
Disadvantages: Cost. The ClearPlan monitor sells for around $200. Test sticks are extra, with a 3-month supply costing approximately $45.