Everything About Ovulation And Our Fern Test


As a woman enters the fertile period of her cycle, higher estrogen hormone levels cause the amount of salt in her saliva to increase.  The increased salt forms crystallization patterns known as “ferning” (because the crystals resemble fern leaves).  By viewing saliva samples under laboratory microscopes with this fern test, medical researchers proved that these ferning patterns became more distinct, as fertility levels rise.

When you see ferning throughout your sample, it indicates the beginning of your fertile window. Differing from LH-measuring urine tests, ferning is a response to your estrogen hormone levels, whereas LH rises about 12-24 hours after estrogen spikes. OvuScope’s fern test does not confirm you are ovulating or did ovulate. It’s a predictor of when ovulation may occur. Typically, ovulation should occur 24-72 hours after the peak ferning pattern appears. During/after ovulation, it is likely that you won’t see any ferning at all.

The fertile window, corresponding to the best time to try to conceive, will be from peak ferning (pre-ovulatory) up to several days later (up to 24 hours after ovulation). Therefore, this method is PREDICTIVE.


Diagram of a non fertile period. Fern Test.


Diagram of rising or declining fertility period. Fern Test.


Diagram of fernlike pattern during most fertile period. Fern Test.

This fern test is a repeatable and non-invasive way to predictor your ovulation. You can use the ferning method with other methods, too, like monitoring your basal body temperature or keeping track of your cycle on a period app. You can even input the information you learn from the OvuScope into a period tracking app, which helps the app understand your cycle better!

Let’s talk ovulation 101

Woman Silhouette

You might be wondering how to determine ovulation date. Let’s start with the basics.

Ovulation is the release of an egg from one of a woman’s ovaries.  After the egg is released, it travels down the Fallopian tube, where fertilization by a sperm cell may occur. This ovulation window can be several days, with typically one peak day on your ovulation calendar. This usually occurs around the middle of the menstrual cycle, about two weeks before your next period starts. However the ovulation window can vary between different people.

If you’re trying to get pregnant, it’s critical to keep track of if/when you’re ovulating and predict the day using an ovulation calculator method, so you can try at the best possible time.


Figuring out how you ovulate can be a struggle, but that’s why the OvuScope was designed and tested by an obstetrician to ensure you can monitor your cycle at home, without worrying about time-consuming and expensive trips to the doctor. The OvuScope’s large viewing area and lab-quality optics make it easy for you to observe crystallization patterns and track your fertility cycle.

Pregnant women and man conversing