H.W.
That would be a sign of possible fertility.
Do you have any other access to information about fertility and charting?
There is a fabulous book "Taking Charge of Your Fertility" by Dr Toni Weschler. It has some charts you can copy for taking basal temperatures, etc. and lots of information in general. If you are TTC, this book can help you understand your body's signs.
And there are ovulation tester kits, too, for a more scientific approach.
Good luck.