[ddaria]

[info copied from MaybeMOM, I claim no copyright]

• When a woman ovulates, estrogen hormone levels in her system rise, which also causes the amount of salt in her saliva to increase.
• Placed on a microscope slide, crystallized salts in dried saliva produce a distinct “fern leaf” pattern if a woman has begun to ovulate.
• The phenomenon of ferning was first discovered in 1945 by Papanicolau, who observed microscopic crystal formations in cervical fluid.
• Subsequent researchers have studied the ferning of other body fluids, including saliva, and have validated the accuracy of the Fern Test in determining a woman’s time of ovulation.