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Microscope
Apply a tiny saliva sample to the lens and let it dry. Saliva crystallises as you enter your fertile window.
Saliva fertility test · CE marked
Find out when you are most likely to get pregnant.
Babyndex pairs a reusable pocket microscope with a mobile app that reads the fern-like crystal patterns in your saliva — so you know your fertile window, not just the day of ovulation.
The app is under development and is intended for informational purposes only, not as a medical device.
Conception probabilityPregnancy probability
Two days before ovulation, not the day of.
Pregnancy is 3–5× more likely when intercourse happens 2 days before ovulation than on the day itself. Most tests tell you ovulation is happening — by then, the most fertile window is already closing.
Saliva starts to crystallise as estrogen rises in the days leading up to ovulation. Babyndex catches that signal early.
What is Babyndex?
Three small things, working together every morning.
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Application
Hold the microscope against your phone camera and take a photo. The app recognises the crystal patterns.
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Calendar
Our algorithm scores the patterns and shows the days with the highest chance of getting pregnant.
Why Babyndex is different.
Actual
Saliva crystallises on your real fertile days — works even with irregular cycles, no months of temperature data required.
Accurate
A 2018 Harvard Medical School study found automated saliva crystal detection predicts ovulation with over 99% accuracy.
Affordable
The microscope is reusable — use it as many times as you want. More sustainable than single-use hormone strips.
From the blog
Our most-read posts on ovulation and the fertile window.
When is my ovulation day?
Cycle length varies, and so does ovulation. Learn how to pinpoint your ovulation day.
When is a woman the most fertile?
The fertile window is short — and the days before ovulation matter most.
Home ovulation tests: regular vs irregular cycles
How LH strips, basal body temperature, and saliva tests compare — and which works best for regular vs irregular cycles.
How to use Babyndex for ovulation prediction
A short walkthrough of the daily saliva test and how the app reads the pattern.
Interpreting the saliva fern test
What dots, lines, and full ferns mean — and how the app removes the guesswork.
Is Babyndex right for you?
A quick check before you start.
Hormonal contraception
The test relies on pre-ovulatory estrogen. Hormonal contraceptives suppress that signal, so it only works if you are not using them.
PCOS
With PCOS, saliva patterns may look different, but the test can still show your actual fertile days. Try it for a full cycle.
Irregular cycles
Unlike LH strips or temperature tracking, saliva crystals show the real fertile window as it happens — no perfect cycle needed.
Try the saliva fern test for one full cycle.
If it doesn't work for you, send the microscope back and we'll refund its price.