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  » Infertility  »  Screening tests for female fertility and remaining egg supply - ovarian reserve

Screening tests for female fertility and remaining egg supply - ovarian reserve
Testing women that have not tried to get pregnant
Testing women in the general population, rather than testing infertile women

This page will focus on tests of female fertility potential that might be useful in the general population . This page is not directed at infertility patients. Other pages on this site deal more extensively with specific fertility tests and issues for infertile women, such as : ovarian reserve, antral follicle counts, female age and day 3 FSH.

For the most part, women go through life without any knowledge at all about the status of their remaining fertility potential. Many women put off trying to get pregnant until a convenient time in their lives, and by the time the "right time" comes, their fertility potential might be reduced - or gone forever. Female age is a variable that is often used by physicians (and others) to counsel women regarding the question of when they should "get going". Age can certainly be helpful in this regard, but chronological age is only one important variable. Some women are still fertile at 42 (very few), while others (very few) are in menopause - completely out of eggs - at 25. 

What we need is a test that tells us the "reproductive age" of the woman. In reality, this ends up being a combination of her actual age (per the driver's license) and her "ovarian age". In other words, if she is 38, are her eggs "38 going on 44", or "38 going on 32", etc. This is what the ovarian reserve tests are supposed to help with.

We have some screening tests that are supposed to help answer these questions, but they are far from perfect.

Antral follicles are small follicles (about 2-8 mm in diameter) that we can see - and measure and count - with ultrasound. Antral follicles are also referred to as resting follicles. Vaginal ultrasound is the best way to accurately assess and count these small structures. In my opinion, the antral follicle counts (in conjunction with female age) are by far the best tool that we currently have for estimating a woman's remaining fertility potential (ovarian reserve). Ovarian volume measurements (also done by ultrasound) and day 3 FSH and estradiol blood tests are additional studies that can also contribute useful information.

Presumably, the number of antral follicles visible on ultrasound is indicative of the relative number of microscopic (and sound asleep) primordial follicles remaining in the ovary. Each primordial follicle contains an immature egg that can potentially develop in the future. In other words, when there are only a few antral follicles visible, there are less eggs remaining as compared to when there are more antral follicles visible. As women age, they have less eggs (primordial follicles) remaining - and they have less antral follicles visible on ultrasound.

Normal ovarian volume and "normal" antral follicle counts
Low ovarian volume and low antral follicle counts
Ultrasound image of an ovary at the beginning of a menstrual cycle
The ovary is outlined in blue
There are 9 antral follicles visible - marked with red dots
Good antral count - also good ovarian volume
Ultrasound image of an ovary at the beginning of a menstrual cycle
The ovary is outlined in blue
Only 1 antral follicle is present - red dot
Very poor antral count - also very low ovarian volume

How many antral follicles is "good"?

There is not a perfect answer to this excellent question. Unfortunately, we do not live in a perfect world, and some ovaries have not yet read up on antral follicle counts. However, the table below gives my opinions, based on our experience using antral follicle counts on thousands of women over several years.

In my experience , here are some general guidelines:

Total number of antral follicles

Expected fertility potential for women under about 37
For 37 and older we need to be more cautious - low antrals and late 30's or early 40's is significantly worse

Less than 4

Extremely low count.
I think that there is a high risk of poor fertility potential.


Very low count.
I think fertility issues are possible - either soon, or within several years (very hard to predict).


Intermediate count.
It is possible that some fertility issues are already present.
I am concerned about fertility issues sometime in the future. It appears that the clock is ticking faster than we'd like...


Low end of the average range.
I am not worried at all yet.
However, as antral counts drop over time, fertility issues might develop.

Over 14

Normal count.
I expect excellent fertility potential. At least for now, the clock seems to be ticking at a normal rate.

How can women get this test done?

It might not be easy, depending on where you live. The test has been in use since about 1998. Currently, antral follicle counts are being performed by some (? many) fertility specialists (including us). Very few gynecologists or radiologists are performing the test. Eventually, I believe that this test will be taught to physicians in other fields of medicine (OB/GYN, Radiology, etc.) and could eventually become a standard part of the annual exam performed on women - along with her breast exam, Pap smear and general physical exam.

Why not? Instead of her OB/GYN telling her, "Don't worry, you're only 33, you have lots of time left to have babies", she could be told, "You have 20 antral follicles, and that combined with your age of 33 predicts that, at least for now, your fertility potential is still good.

Recommendations for fertility screening in women that have not yet tried to get pregnant

  • Have day 3 FSH and estradiol blood tests done - read day 3 FSH levels for details regarding interpretation
  • If you can get antral follicle counts and ovarian volume measured, do that also

If you are 37 or older and "don't have a man" and want to have kids someday - start looking over the guys - I hear there's a few good ones left...

If you are 37 or older and do have a man and want to have kids someday - consider getting going soon...