As ovulation approaches, levels of estrogen and salt build up within your saliva. This can be detected with a microscope because when your saliva dries a pattern forms, known as "ferning" for its resemblance to fern leaves.
What Do I Have to Do?
This test must be conducted first thing in the morning before eating, brushing your teeth, or smoking (which isn’t recommended during any time of day, particularly if you’re TTC). Kits typically include a microscope, reusable lenses, and an image guide, so you know what to look for. Simply place a drop of saliva from under your tongue on the lens and allow it to dry for five minutes. Take a peek and see of you’re fertile!