Confirm ovulation with progesterone in the luteal phase

When it comes to your fertility and cycle, it helps to have something concrete to go on. After ovulation, the corpus luteum in your ovary produces progesterone, which is why this hormone rises in the second half of your cycle.

By measuring progesterone around day 21 of a roughly 28-day cycle, a test can give an impression of whether ovulation has likely taken place. It is a commonly used way to understand your cycle a little better.

This test can be useful if you want to know more about your ovulation. Think of women with an irregular cycle, women who are trying to conceive, or those who are simply curious whether they ovulate.

If you already track your cycle with, for example, temperature readings or ovulation strips, measuring progesterone in your blood can be an extra piece of the puzzle. It says something about the phase after ovulation.

This test measures a single hormone in your blood:

• Progesterone: produced after ovulation by the corpus luteum in your ovary. A raised value in the second half of your cycle can fit with ovulation having occurred.

Because progesterone fluctuates strongly across your cycle, timing matters. The value is most meaningful when you have blood drawn around day 21 of a 28-day cycle.

Your progesterone value can give an impression of whether ovulation likely happened in that cycle. A clearly raised value in the luteal phase (the second half of your cycle) often fits with ovulation.

A lower value can sometimes suggest that ovulation may not have taken place in that particular cycle, or that the sample was taken at a slightly different moment. It is one snapshot, which is most informative alongside your cycle and your wider situation. The test cannot establish with absolute certainty that ovulation occurred.

This test requires a small blood draw at a certified sample point. In the Netherlands you can choose from 700+ locations.

After ordering, you pick a location near you and book an appointment on the right cycle day. The draw itself usually takes only a few minutes, and you do not need a referral from your GP.

A progesterone test can be valuable at different moments, for example:

• when you want to know whether you ovulate, especially with an irregular cycle
• when you are trying to conceive and want to understand your cycle better
• as a complement to an ovulation test, alongside other signals you already track
• when you want more insight into the second half of your cycle

Timing is precise: the measurement is usually done about seven days before your expected period. In a 28-day cycle that works out to day 21, while a longer or shorter cycle shifts this day.

Your result shows your progesterone value together with a reference range and a short explanation. What counts as usual depends on the phase of your cycle and varies by laboratory.

A value above a certain threshold in the luteal phase can fit with ovulation, while a lower value can mean different things. The doctor helps you place your value in the right context.

Your result is usually available online within a few working days. Each value is shown clearly with a reference range and an explanation, so you understand what you see.

Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.