Fertility Monitors enable women to check their fertility levels on a daily basis. They vary in their methodology and accuracy.
If you use natural family planning methods, using a fertility monitor may be able to help you avoid pregnancy. A fertility monitor works best in women who have regular 27-35 day menstrual cycles. More irregular cycles may make it difficult to pinpoint ovulation.
Types of Fertility Monitors
Urine-based fertility monitors
Fertility test sticks and other similar products use urine samples to measure luteinizing hormone (LH). These tests are the most commonly used fertility monitors and, generally speaking, they are accurate in their ability to measure LH. There are differing opinions regarding whether or not monitoring LH levels reduces time to conception. The Clearlue fertility monitor measures estrogen in addition to LH. It should be noted that clomiphene citrate (Clomid) can interfere with the results of LH testing.
Saliva-based fertility monitors
Saliva-based monitors measure the salinity levels in saliva. Salinity levels increase along with estrogen levels, so the salt serves as a proxy. The test is visual: you allow a saliva sample to dry then examine it under a microscope (included with most kits). The pattern exhibited by the dried saliva indicates the level of salinity.
Simply monitoring your basal body temperature (your body temperature taken immediately when you wake) can give you an idea of when you are ovulating; ovulation may cause a slight temperature rise. By charting the temperature you may be able to discern a pattern and you should be most fertile a few days before the increase. There are also skin-based products available that monitor perspiration and temperature.
Cervical Mucus Self Test
A self-administered cervical mucus test is another means of monitoring fertility. The fingers are used to collect a cervical mucus sample. By observing the consistency of the mucus, one can judge how close one is to ovulation. Despite the non-technical nature of this test, it is quite accurate when done properly.