What you should know about your eggs

You can test the quality and quantity of your eggs, but are the tests reliable?

More and more women are getting their eggs checked. We look at the tests available and how reliable they are as a guide to fertility.

Egg quantity – also called the ovarian reserve – is the number of eggs a woman has available to get pregnant. How many healthy eggs do you have stored in your ovaries?

It’s an important question because the higher the number of normal eggs you have, the greater your chances of having a baby.

This may seem like plenty, but that’s not how it works. The quality of the eggs declines, too, and this affects fertility: healthy eggs are essential for a successful IVF cycle and a live birth. So, nature plays a cruel trick by letting millions of eggs decay before you want them for a baby.

A woman can have monthly menstrual cycles and have sex on the day she is most fertile, but if the egg is poor quality it won’t fertilise or it will lead to a miscarriage.

There are also higher risks of having a child with an abnormality such as Down’s syndrome.

Low ovarian reserve is a premature decrease in the number of eggs and there can be a number of causes. Fewer eggs mean fewer embryos to choose for the embryo transfer. What makes it more complicated is that a 40-year-old can have some good quality eggs and still be fertile, while a 25-year-old can have poor quality eggs and be infertile. One young woman discovered she was infertile after offering to donate her eggs to a childless couple.

These examples are rare, but it shows that guesswork isn’t reliable.

What tests are available?

  1. Follicle stimulating hormone (FSH) and oestradiol test

FSH is one of the most important hormones needed for the natural menstrual cycle. FSH helps to control the menstrual cycle and the production of eggs by the ovaries. This test measures the amount of FSH  a woman is producing and is taken from a blood sample. It’s usually taken on day three of the menstrual cycle. If you have a good ovarian reserve, your body doesn’t need to make very much FSH to help eggs grow. If the levels of FSH are too high, it indicates that the body is harder than it should be to stimulate the follicles for growth. It’s a sign of poor egg quantity (and possibly quality). What’s needed is a low FSH level and a low oestradiol level. If the FSH is normal but the oestradiol level is higher than normal, this can artificially lower the FSH level down to the normal range and give an incorrect reading.

Is it accurate?

  • Readings can vary from cycle to cycle and it will be affected if you are taking the contraceptive pill
  • Some women with normal FSH values have a reduced egg supply but this doesn’t show up, so other tests are needed (see below)
  • FSH may only rise once egg numbers in the ovary are already very low
  • Many medicines can change your test results – check with your doctor and clinic if you are taking any prescription and over-the-counter medicines, as well as herbs and natural substances
  • Recent tests using a radioactive tracer (such as a thyroid scan or bone scan) can interfere with FSH test results
  1. Anti-Mullerian Hormone (AMH) test

AMH is a hormone produced by growing follicles in the ovary. The more eggs you have, the higher the AMH result. Low test results can predict issues with ovarian reserve. Because the levels of AMH in the body don’t vary much, the test can be taken any time.

Women with higher AMH values will tend to have better response to ovarian stimulation for IVF and have more eggs retrieved. In general, having more eggs with IVF gives a higher success rate.

Is it accurate?

  • AMH readings don’t change much between cycles
  • It’s not significantly affected by hormonal medication
  • It is more accurate ‘snapshot’ of egg quantity and can be helpful in estimating the number of eggs that would be collected
  • AMH levels probably do not reveal much about egg quality, but if you know there are a good number of eggs available during IVF, there’s a higher chance of finding at least one high quality embryo for transfer back to the uterus.
  • Some laboratories will give ‘normal ranges’ for AMH that do not take age into account and may be misleading so make sure you ask the clinic to factor in your age for the test
  • The AMH test is complex, so occasionally the reading will be wrong – if your reading is unusual, get it tested again to make sure
  1. Antral Follicle Count (AFC) ultrasound test

 This test counts your antral follicles (or ‘sleeping’ follicles) in both ovaries using ultrasound. If a woman has a good number of follicles visible, this indicates a normal ovarian reserve. If only a few can be seen, the reserve is lower. The ideal AFC is 15-20 over the two ovaries. Less than ten is low.

Is it accurate?

  • It depends on the skills of the technician – not every clinic has an ultrasonographer who is expert at measuring AFC
  • The readings can vary because not clinician measures in the same way
  • It depends on the quality and age of the machine (the latest 3D scanners are better)
  • The readings can be more difficult to do accurately if you are gassy or overweight
  • Clinicians will be able to see if the womb is abnormal in any way, diagnose PCOS and assess any other risks and see what’s needed to help achieve pregnancy (IVF or not)

Stimulating the ovary can reveal clues

When ovaries are stimulated for an IVF cycle, they can provide vital information on egg quantity (how does the ovary respond to a particular dose of stimulation?) and egg quality (what
do the eggs and fertilised embryos look like when assessed in the laboratory?).

This can often confirm what’s revealed by other tests of ovarian reserve and the information can be used to change strategies in future IVF cycles to improve your chances of getting pregnant.

None of the tests are perfect but…

As you can see, there is no magic test that can predict egg quantity or quality with 100% accuracy and help you see into the future.

If you have a low ovarian reserve, a clinician can adjust the ovarian stimulation protocol to try to increase the number of eggs you produce.  If it looks as is if will take too much stimulation using a high quantity of medication to get more than a couple of eggs, then a natural cycle or low stimulation protocol may be the way to go. This avoids the high cost and effort and may obtain the same results. Talk to your clinic about this.

These tests are also valuable because they can flag up any problems including polycystic ovary syndrome (PCOS) and blocked fallopian tubes. By doing multiple ovarian reserve tests, you are more likely to find an ovarian reserve problem if there is one.

No wonder more and more women are using them.

These tests are not your only measurement of future success.

There are many other factors that come into play as we age, but the tests are still a valuable start on the road to having your own child, with or without IVF.

Do home fertility tests work?

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