If you want to invest in a good fertility monitor, the Ovacue Fertility Monitor is, at this price range, the top one on the market. This monitor does not require the use of urine, nor does it require the purchase of anything extra like test strips, other than a battery every couple of years.
The OvaCue will alert you days in advance of ovulation, and will again alert you of imminent ovulation then will confirm ovulation occurred after. Used with fertility charting you will see the results verified. I used the OvaCue Fertility Monitor with my last 4 pregnancies. This device works as an excellent *birth control also, if you establish your fertility pattern, and will know when to avoid sexual intercourse.
While it’s a sizable investment, it’s worth it if you plan to use it through more than one pregnancy or may want to use it as *birth control.
*Note: the manufacturer does not make this claim; however, with continued use through the past 10 years, I can see it working as a method of natural birth control very well.
If cost is an important factor but you do not want to compromise, another product to consider for Natural Family Planning or Conception is the Fertility Tracker.