09/01/2026
You took the first step and started charting your cycle, but now you are lost and overwhelmed by all the data.
Lets break it down what all the different data tells you about your fertility.
As a wave of follicles develop they release estrogen, causing the cervix to open and mucus to develop.
The body releases LH around 36-48 hours before ovulation to lutenize the dominant follicle. Estrogen peaks around this time.
The dominant follicle ruptures releasing the egg and collapses into the corpus luteum. The corpus luteum continues to release estrogen for the rest of the cycle.
Progesterone causes body temperature to rise about 1/2 degree Fahrenheit.
You don't have to track all these signs but using a combination gives high certainty ovulation occurred.
Potential fertility begins when the cervix opens, as s***m can live in high quality mucus for up to 5 days.
After ovulation the egg can live for 12-24 hours if not fertilized.
Kegg gives you a fertile window based on your cervical mucus. However in my experience it takes at least two cycles to get an accurate fertile window.
Measuring urinary hormones can give you quantitative insight to your cycle. However it still only gives you a snapshot of your hormones at one time during the day. Certain hormones peak at different times. Estrogen readings can also be influenced by alcohol consumption.
If you want quantitative data, urinary hormones can be a good option. However you can see the same hormone trends in other biomarkers.
Basal body temperature (BBT) rises in response to progesterone the second half of the cycle, creating a biphasic pattern. Using temperature rise to confirm ovulation is well researched and effective.
However temperature CANNOT tell you when the fertile window opens (looking at you natural cycles). You can use an average of temperature rises over the previous cycles and assume the fertile window opens so many days before. However this is not the true opening of the fertile window, which has to be determined with an estrogen sign.
Mucus is the single most informative biomarker. You dont need to see mucus either, most women can tune in