Salivary ferning kits help you tell when ovulation is imminent by showing changes in your saliva. As your estrogen levels rise in the days before ovulation, the salt content of your saliva increases.

Medically reviewed by Cordelia Nwankwo, MD Ovulation test kits, used to track when getting pregnant is more likely, may not be as reliable if you have polycystic ovary syndrome (PCOS). This is because ...