Explaining the Unexplained: Ovulation

Here Alex O’Connor, a fertility acupuncture specialist, from Essex Fertility in her Explaining the Unexplained series explains all about ovulation – how do you know if it’s happening and what can you do if it’s not. Are you ovulating? Just because you ‘feel’ like you are ovulating, doesn’t mean that you are. A regular cycle […]

Here Alex O’Connor, a fertility acupuncture specialist, from Essex Fertility in her Explaining the Unexplained series explains all about ovulation – how do you know if it’s happening and what can you do if it’s not.

Are you ovulating?

Just because you ‘feel’ like you are ovulating, doesn’t mean that you are.

A regular cycle is not proof that you are actually ovulating – it is possible for your body to bleed every month without actually ovulating.

So if you are starting to wonder about your fertility, or if you have been diagnosed with ‘unexplained infertility’, one of the most important things to do is to check that you are actually ovulating. 

How can you tell whether you ovulate

BBT chart

If you chart for a month or two, you should be able to tell from your chart whether you ovulate – if you are ovulating the chart will have a classic biphasic appearance (two distinct temperature phases), with the temperatures of second half of the month registering at 0.5’F or 0.3’C above the temperatures of the first half of the month. This indicates that ovulation has occurred. If the chart is continually in the same temperature range, it suggests that you have not ovulated.

It is well worth investing the time and effort into tracking your cycle with a BBT chart before looking at the next two suggestions. It would give you a rough idea of when you ovulate so that you can time scans and blood tests correctly. If you ovulate on day 22, an ultrasound scan on day 14 or a ‘Day 21 progesterone blood test would both produce very disappointing results. To find out more about the basics of BBT charts, go here.

Ultrasound scan

If you are due to have an ultrasound scan in the second half of the month, your sonographer should be able to see a corpus luteum on one of your ovaries if you have ovulated. If you are having an ultrasound after you have ovulated, check whether they can identify a corpus luteum and check that there are no signs of a luteinised unruptured follicle (see below).

Day 21 progesterone blood test

When a follicle is ready to be released, Luteinising Hormone (LH) is released by the pituitary gland which triggers the rupturing of the follicle to release the egg. The spent follicle goes through a process called luteinisation, quickly turning into something called a corpus luteum which pumps out progesterone. Progesterone is used to prepare the body for potential conception, ripen the uterus lining and upregulate the thyroid. 

If progesterone is detected in your blood, it will have been produced by a corpus luteum, so in theory it is proof that you ovulated – however the amount of progesterone can also indicate the vigour and vitality of the corpus luteum and the potential quality of the egg released by the follicle. It is worth noting though that it is possible for a follicle to fail to release the egg, but to continue to luteinise and produce progesterone (see below for an explanation of an unruptured, luteinised follicle)

The 21 Day Progesterone blood test is designed to test your progesterone level at the peak of production – but timing for this test is critical. The average cycle is 28 days long, and the average ovulation is at around 14 days, so the 21 Day Progesterone tests is designed to capture the progesterone level at the peak in the average cycle. But most of us are not average – read on…

You can request this test from your GP or your fertility consultant, or you can organise your own test through a private blood test service such as Medichecks. The Day 21 Progesterone test is a finger prick test, so you can order the kit and wait until the correct day to take the test.

The 21 Day Progesterone blood test is designed to test your progesterone level at the peak of production – timing for this test is critical. The average cycle is 28 days long, and the average ovulation is at around 14 days, so the 21 Day Progesterone tests is designed to capture the progesterone level at the peak so it is important to time this test to take it at the peak of YOUR progesterone release.

Shorter cycles:

If your cycle is 23/24 days long, your progesterone level on Day 21 will probably register lower than your peak progesterone because the level may already be falling in preparation for your period. If your cycle is short, I would recommend you use a BBT chart for a month to get some information about whether you have a short follicular phase or a short luteal phase, and to work out the best time to measure your progesterone in the middle of your luteal phase.

Longer cycles

If your cycle is 33 days long, it is possible that you haven’t even ovulated by Day 21, so your progesterone test would have a disappointing result that reveals nothing about your true progesterone cycle. If your cycle is regularly long, aim to test your progesterone level 6-7 days before your period is due which should be at around the peak of progesterone.

If your doctor does not understand the importance of the timing of this test, you may have to be creative with the information you give them about when your ‘day 21’ occurs!

Day 21 progesterone test result

If your result comes back to say your progesterone level is over 30nmol/l, it suggests that you have ovulated and that the luteinised follicle was strong, healthy and able to generate a good amount of progesterone.

If your result comes in at less than 5nmol/l it would suggest that you did not ovulate. However that is only a valid assumption if your period started within a week of taking the blood test. If there was a gap of over 12 days between the test and when your period started, it is possible that the test was taken just before you ovulated.

If your result was somewhere in between, it could suggest several things:

  • It could suggest that you ovulated, but that the follicle was not strong or that the thyroid failed to react appropriately
  • It could suggest that the timing of the test was incorrect and that progesterone was not at it’s peak when the test was taken. It is always worth noting how many days passed between taking the test and the next period as this information can help you to interpret the results correctly

So does a good progesterone level ALWAYS indicate ovulation?

No.

Unfortunately it is possible to have a Luteinising Unruptured Follicle – this is something that occurs in approximately 10% of normal menstrual cycles, but is thought to occur more frequently in women struggling with infertility. When this happens the follicle fails to rupture, but does manage to luteinise which is the process that generates progesterone. Basically the egg is trapped inside the follicle and disintegrates, but the luteinising process means the follicle still generates progesterone which in turn is still able to stimulate the thyroid to raise the body temperatures so your ovulation prediction kits, your BBT chart and a well timed progesterone blood test would all indicate ovulation had occurred. 

A luteinised unruptured follicle can be detected on ultrasound but it is not easy to identify and you may need to seek out an expert fertility sonographer to rule this out. It is possible to have a series of ultrasounds repeated through your ovulation window to identify the maturing follicle and to double check that actually ruptures. If a dominant follicle fails to rupture, it will shrink to about half the size and the remnants will contain fluid which is possible to pick up on a scan (if a follicle ruptures and releases an egg the follicle turns into a normal corpus luteum).

There is some evidence to suggest that Clomid can increase the likelihood of Luteinising Unruptured Follicle Syndrome (Qublan et al, 2006).

But what about LH test sticks?

As the dominant follicle gets large enough, it secretes a significant amount of oestrogen which triggers the release of Luteinising Hormone (LH) from the pituitary gland. In some instances there multiple oestrogen generating follicles may cause high oestrogen levels which can trigger LH before an egg is really ready for release – so an LH surge could be detected, but no egg release is triggered. It is possible for LH release to be triggered more than once in a single cycle, as the feedback mechanism for LH release can be set off multiple times.

Some people also have a very high LH throughout the cycle, which can make LH testing strips unreliable. When I have seen this in my clinic, further investigation has shown an elevated prolactin level, suggesting that the pituitary hormone regulation system was generally a bit out of kilter.

What about cervical mucus?

Production of cervical mucus is a response to the rising oestrogen level, but it does not guarantee that there is a single, dominant follicle maturing or that it will rupture and release an egg. It is possible for multiple smaller follicles to generate enough oestrogen to trigger cervical mucus production.

So what can you do about absent ovulation?

Lots.

Diet, lifestyle and acupuncture can all have an incredible impact on your menstrual cycle and help to turn a non-ovulatory cycle into an ovulatory cycle. I would recommend working with a Fertility Support Trained Acupuncturist who would be able to work with you to investigate what is happening and treat you to restore regular ovulation. We work in a particularly integrated way, blending western medicine diagnostics with ancient acupuncture knowledge to restore and rebalance your cycle and improve your fertility.

Read more about Alex and Essex Fertility here.