STEP 2
Once you determine the length of your menstrual cycle or an average number of days, you can use the chart below to help determine the day you should begin testing. On the top row of the chart, find the number that corresponds to the length of your menstrual cycle. Directly below that number is a smaller number. This is the day of your menstrual cycle when you should begin testing.
Example
Here’s an example: Sally Smith has a regular menstrual cycle of 28 days and started her period on the 4th day. Beginning with the 4th as Day 1, she counts forward 11 days and begins testing on the 14th.