Since over 30 years the natural method to monitor your menstrual cycles with accuracy.

The menstrual cycle and ovulation

Take a journey into yourself and discover the wonders of your menstrual cycle. Learn the basics to gain control and feel confident with your fertility.


Day one of a menstrual cycle is always the first day of bleeding. Light spotting is not necessarily the start of your next menstruation since it can also happen during ovulation.

A normal menstruation lasts between 3 to 5 days.

The last day of a menstrual cycle is always the day before bleeding starts again.

Cycle lengths are variable

Any cycle length between 23 and 35 days is considered medically normal.

Cycle lengths vary naturally during a woman's fertile life but tend to be more stable between 20 and 45.

Ovulation fluctuates

The body releases a well balanced mix of natural hormones to induce or hamper the growth of follicles and initiate ovulation. This fine tuned hormonal balance in the follicular phase before ovulation is subject to many influences.

That is why the day of ovulation may vary greatly, from cycle to cycle. Studies repeatedly confirm that ovulation on cycle day 14 or 15 happens only in one out of 4 cycles.

Ovulation is 10 - 16 days BEFORE menstruation

As Knaus and Ogino found out, most women with a healthy hormonal balance have an average of 13 days between ovulation and menstruation. This very stable luteal phase is dominated by progesterone, the pregnancy hormone.

The phases of the menstrual cycle

Even though cycle lengths and the day of ovulation may vary greatly, each fertile cycle has 4 typical phases.

The 4 phases of the menstrual cycles

Let's look at them in more detail:

Infertile follicular phase

This highly variable phase begins with the first day of menstruation (M). The first 5 days are reliably infertile in over 99% of all cycles. The total number of safely infertile days depends on many factors.

Fertile follicular phase

On the 5 fertile days before ovulation, temperatures are low and the cervix soft and open. The now stretchy mucus is nourishing and protecting sperm. Only under these conditions can sperm survive 3 to 5 days awaiting ovulation.


Ovulation is on the first day of higher temperatures or on one of the 2 days before. After ovulation, the egg lives for only 12 to 18 hours. The following massive raise of progesterone prevents further ovulations.

Infertile luteal phase

Progesterone closes the cervix, dries mucus and sperm can no longer survive. But only the typical temperature shift followed by stable higher temperatures indicate that ovulation really took place and the infertile phase began.

Lady-Comp knows all of that

Analyzing a regular cycle is great fun and relatively easy to learn. But what about the crazy, infertile or irregular cycles?

This is when experience and the knowledge from 30 years of charting makes all the difference. The Lady-Comp program compares your unique temperature pattern day to day with the data from over 100,000 menstrual cycles to detect your ovulation and your safe infertile days. Fast and easy.

So the next time your menstruation is late, you will know exactly if you are pregnant or if your ovulation was just a bit delayed.