One newer method of birth control is a small electronic fertility computer which tells a woman which days she is fertile. One popular model is the German LadyComp device that determines fertility based on a woman's temperature. Computers like these (LadyComp and BioSelf, top right) measure and store basal temperature readings, detecting when a woman is fertile by the temperature increase that occurs after ovulation. A green light on the device means infertile; a red light means fertile. The LadyComp device can be used by women with longer or irregular cycles, such as those experienced postpartum. Manufacturers claim failure rate of less than 1% for perfect users, and 4% for typical users.
With the Persona model (bottom right) fertile days are indicated with a red light and infertile days with a green light. If the light is yellow, the woman takes a urine test which changes the light to green or red, based on the amount of hormone found in the urine. This method is now available in Europe and Canada, where manufacturers boast a failure rate as low as 6% per year among women who abstain on fertile days as indicated by the device.
Advantages & Disadvantages
Clinical trials are now being conducted to obtain FDA approval for fertility computers, but these monitors are not currently on the market in the United States and must be ordered from overseas. Advantages of these methods is that they involve no chemicals or hormones, and charting body signs is not necessary.
Disadvantages include the initial expense of the computer and, in the case of Persona, the need to purchase urine test sticks for use eight days out of each cycle. Additionally, these methods are currently only being recommended for women whose cycles are between 23 and 35 days. More research is needed to determine accurate failure rates for typical users.