Should you see an Ob-Gyn (gynecologist) or RE (reproductive endocrinologist)?


Women are born with one to two million eggs. Every day of her life a woman keeps losing eggs—approximately 1,000 each month.

Some women are born with fewer eggs and some lose their eggs at a faster rate (there are genetic factors behind this).

As women age, various kinds of damage (e.g., genetic mutations and deletions) accumulate in the energy-producing system within their eggs (mitochondria), making them less functional and capable of becoming fertilized.

All these factors contribute to what is called “diminished ovarian reserve,” which is a mean diagnosis because there is no real disease behind it, only a simple, unavoidable biological aging.

Women with diminished ovarian reserve frequently have a hard time getting pregnant. One of the signs that the ovarian reserve is a shortened menstrual cycle.

If you have always menstruated every 25–30 days and suddenly start to menstruate every 24–26 days, then this could be a pretty certain sign that your egg reserve is diminishing and you should evaluate this.

The most certain marker of ovarian reserve is age.

The relation is very simple: young women have eggs of superb quality and easily fertilized and give viable embryos.

Eggs of older women, on the contrary, have lower quality and miscarriages are more frequent.

If you are over 30 and trying to get pregnant, then you want to know where you stand.

Ovarian reserve testing should be performed routinely in women older than 35 who have not conceived after 6 months of attempting pregnancy.

How is a woman’s fertility tested?

In many cases, gynecologists may be able to treat some areas of infertility. Depending on a country, gynecologists can prescribe certain fertility medications like Clomid to stimulate ovulation. Some OB/GYNs are also allowed to perform intrauterine insemination (IUI). In any case gynecologists can order various important blood tests.

Which hormones are used to test fertility?

The first and the most appropriate test to use to test fertility is the AMH level.

AMH can be tested in the blood on any day of the cycle.

In addition, you need to find out your antral follicle count (commonly known as an AFC number). This is also an easy-to-perform ultrasound check (antral follicles are best visible at the end of one cycle and the beginning of the next).

Combining these two results (AMH and AFC) should be the first step in assessing fertility and this can be done by an Ob-Gyn.

However, if this first step fails (meaning the AMH turns surprisingly low or too few antral follicles appear on the ovarian surface) you should move to the next level—that means visiting an RE (reproductive endocrinologist).

Gynecologist (OB-Gyn) or RE (reproductive endocrinologist): What’s the difference?

In all things hormones, the RE is much more skilled then an Ob-Gyn and knows which other tests might be needed (and how to put the data together) to determine your fertility status.

In reality RE is an OB/GYN who has received additional, extensive training and certification in infertility issues. That’s why women over 35 should not waste too much time before switching from an Ob-Gyn to a RE.

ovarian reserve normal range

One of the first parameters that a reproductive endocrinologist will want to know is your FSH level.

FSH is best measured at the beginning of a cycle (day 2–3).

If the FSH value turns out to be <10 mIU/mL, you’re fine.

If the basal FSH turns out to be 13–20 mIU/mL, then it is a sign of a diminished ovarian reserve and suggests not only that you have a few eggs left, but they may be of less than excellent quality. For those in need of IVF, this also means that ovaries might respond poorly to stimulation drugs and build only a small number of follicles.

However, there is a huge grey area in the FSH range of 10–13. In this range, you are faced with questions such as: “Should I start with the IVF immediately, or should I wait and try to conceive naturally?”, “How long should I wait?”etc. And there are no clear-cut answers to these questions.

A question I am often asked is how much should a woman be concerned about a single elevated FSH readout? That is, FSH level smostly stay within the nice range of 6–10, going up only once or twice? How seriously should that be taken?

The thing is, with a constantly elevated FSH, you are likely to have a very, very low ovarian reserve. In this sense, FSH that elevates only once is certainly a better scenario.

However, even a single bad FSH result indicates a diminished ovarian reserve. That’s why FSH should be measured more than just once to catch this variation (and always on cycle day 2–3).

There are other possible confusions related to day 3 FSH (and that’s why it’s important to talk to an expert instead of wasting time).

It happens sometimes that women who have a severely diminished ovarian reserve still have an FSH of less than 10mIU/mL!

How is that possible?

What is suppressing their FSH?

The answer is high estradiol.

That’s why an estradiol test MUST accompany any day3 FSH measurement.

This is what actually happens in the body:

In women with severely depleted egg reserves, FSH becomes quite high before the menses starts. This means that follicle recruitment starts way too early.

Instead of waiting for the new cycle to begin maturing, the follicles start to grow in the days before menses even flushed the previous cycle’s rest. In that way, the lead follicle is advanced in size by Day 3 and has secreted enough estrogens to suppress the FSH and give a false picture by way of a reassuring FSH result.

That’s why the measurement of estradiol needs to accompany the FSH measurement on Day 3, always.

If the estradiol is less than 70pcg/ml and the FSH<10, then you are fine.

However, if estradiol is greater than 70 on the third cycle day, then this may have the same prognostic value as an elevated FSH!

In summary, day 3 fertility blood work should include both FSH and estradiol.

If you need a second opinion on anything related to the ovarian reserve, then it’s possible to contact me and set up a Skype appointment; also, you can contact me as described here if you’re unsure about whether you’re taking the right supplements.


2018-06-18T09:52:49+00:00 November 7th, 2016|Tags: , , |

About the Author:

Darja Wagner, a PhD cell biologist combines her knowledge of cells, hormones and vitamins to help women with infertility issues. She is the author of the blog "All About Egg Health: How to Get Pregnant After 35". Darja helps women to apply latest advances in reproductive biology to maximize egg quality for higher chances of conception, in either a natural way or by means of assisted reproductive technology.