Can a Woman’s Egg Count Be Measured with a Blood Test?

By (gynecologist), (embryologist) and BSc, MSc (embryologist).
Last Update: 06/08/2021

There are several tests to detect the number of eggs a woman has at the time she wants to become pregnant. However, screening for fertility-related hormones is a non-invasive test that is performed with a simple blood draw and provides reliable information about a woman's reproductive status.

It is usual that the study of female fertility includes a blood test where the levels of hormones such as FSH, LH, Estradiol, Antimullerian and inhibin B. Based on the results obtained, you can determine the ovarian reserve of women.

How does ovarian reserve evolve?

A woman is born with a set number of eggs, known as the follicular ovarian reserveor follicular, and this does not increase with age. On the contrary, this number decreases throughout their reproductive life until it reaches zero at menopause.

That is why it is necessary to find out how the ovarian reserve is at the time when the woman wants to get pregnant, as it gives us information about the chances of getting pregnant naturally or if she will need the help of assisted reproduction.

Number of eggs at birth

From the time the eggs begin to form in the foetus until the girl reaches reproductive age, the number of primordial follicles decreases drastically until the ovarian reserve is constituted.

20th week of fetal development during pregnancy
the female fetus has about 6 million immature eggs produced in ovogenesis, contained within primordial follicles. This will be the maximum number of primordial follicles you will have in your lifetime.
Birth of the child
the number of primordial follicles has already decreased to 1-2 million.
First menstruation or menarche
the number of primordial follicles has dropped to 500,000. At this time, what is known as follicular recruitment begins.

Follicular recruitment

In each menstrual cycle 1,000 follicles begin to mature, of which only 20 will mature into antral follicles. In response to the gonadotropins, one will become a pre-ovulatory follicle, and will expel the egg from inside it into the fallopian tubes, where it can be fertilized by a sperm. The remaining follicles that do not reach the pre-ovulatory stage are lost, a process known as atresia.

The gonadotropins are LH and FSH, which are secreted by the pituitary gland and are involved in egg maturation.

Ovarian reserve decreases with age

With each menstrual cycle, about 1,000 follicles are lost from a woman's ovarian reserve as a result of a subtle, biologically controlled process of ovarian deterioration. That is why age is a determining factor for the achievement of pregnancy.

When a woman begins the process of looking for a pregnancy, she does not know the state of her ovaries and her ovarian reserve, as this does not necessarily have to be the same in women of the same age. There are young women with diminished ovarian reserve compared to older women.

Thanks to the analysis of certain sex hormones in the blood, it is easy to respond to these women and check their reproductive status. In addition, this analysis is also used by assisted reproduction specialists to decide which is the most appropriate treatment for each woman. If a woman has a good ovarian reserve, she could try fertility treatment using her own eggs. However, if the patient has a low ovarian reserve, it would be best to opt for donor eggs.

Assisted procreation, as any other medical treatment, requires that you rely on the professionalism of the doctors and staff of the clinic you choose. Obviously, each clinic is different. Get now your Fertility Report, which will select several clinics for you out of the pool of clinics that meet our strict quality criteria. Moreover, it will offer you a comparison between the fees and conditions each clinic offers in order for you to make a well informed choice.

If you would like more detailed information, we recommend you visit the following article: How Many Eggs Does a Woman Have? - Your Egg Count by Age.

Hormones that are detected in the blood

The hormones that regulate a woman's menstrual cycle are markers of ovarian reserve. These include follicle-stimulating hormone, luteinizing hormone, antimullerian hormone and estradiol.

The following is a list of each of them and how they allow the measurement of the number of eggs.

Antimüllerian

Anti-Müllerian hormone or AMH is considered the most important hormone for measuring ovarian reserve, because unlike the others, this hormone does not vary throughout the menstrual cycle. Therefore, the blood test can be done at any time for the determination of antimullerian hormone.

AMH is expressed in granulosa cells in the ovaries throughout a woman's reproductive life, from puberty until she reaches menopause. Specifically, what this hormone indicates is the number of antral and pre-antral follicles, which, when mature, will produce fertilizable eggs. Therefore, it is considered an indirect analysis of ovarian reserve.

As a woman ages, her AMH values decrease, indicating that the number of eggs in the woman's body is being depleted.

AMH levels between 0.7 and 3.5 ng/mL are considered normal. Levels below 0.7 ng/ml are associated with decreased ovarian reserve.

If you want to continue reading about the anti-Müllerian hormone, you can check the following link: What Is the Function of Anti-Müllerian hormone (AMH)?

FSH

The follicle stimulating hormone or FSH, is a hormone secreted by the pituitary gland that acts on the ovary and intervenes in the development and maturation of the follicles where the eggs are found. As a woman gets older, more FSH is needed for egg maturation. For this reason, high FSH values indicate low ovarian reserve in women.

In contrast to AMH, the FSH test should be performed between days 3 and 5 of the menstrual cycle, so it is a baseline test.

FSH levels above 10 mIU/ml indicate low ovarian reserve.

If you want to continue reading about FSH, you can check the following link: What Is the Role of Follicle Stimulating Hormone (FSH)?

Inhibin B

The concentration of inhibin B is inversely proportional to FSH values, the higher the amount of inhibin B in the blood, the lower the concentration of FSH hormone. Its serum determination is a good indicator of follicle function and ovarian reserve.

An inhibin B value of less than 35-40 pg/ml reveals alterations in ovarian reserve.

Estradiol

Estradiol is a hormone secreted by the preovulatory follicle in the ovary. Therefore, at the beginning of the menstrual cycle, the estradiol value should be low, as the follicle has not yet begun to mature. High estradiol values at the beginning of the menstrual cycle are related to a low ovarian reserve, although it is not one of the best markers to measure the number of eggs.

Values of estradiol at the beginning of the cycle greater than 40 pg/ml are related to low ovarian reserve.

For more information about this hormone, you can visit the following article: What are estrogens - types, functions and drugs.

FAQs from users

Can treatment delay the decline in ovarian reserve?

By Concha Leal Cariñena (gynecologist).

No. Combined oral contraceptives (OCPs) and GnRH analogues do not guarantee delayed oocyte loss.

Is it possible to measure ovarian reserve with a home method?

By Zaira Salvador BSc, MSc (embryologist).

No, the only way to know the number of eggs a woman has reliably is through the blood test discussed in this article, or by observing the antral follicles by ultrasound.

There is a home test to measure basal temperature, but it is only useful to know if ovulation is occurring.

What are the causes of diminished ovarian reserve?

By Zaira Salvador BSc, MSc (embryologist).

The main cause is age. There is an inversely proportional relationship between age and the number of eggs available to mature.

However, there are other factors that can negatively affect ovarian reserve, such as medical treatments, drugs, obesity, endometriosis, etc.

How many eggs does a woman produce in adulthood?

By Zaira Salvador BSc, MSc (embryologist).

Females are not capable of producing eggs in adulthood, but are born with a number of eggs already established for the rest of their reproductive life. The opposite is true for men, who are able to produce spermatozoa de novo in a process known as spermatogenesis.

By Marta Barranquero Gómez (embryologist).

There is no ideal age for assessing ovarian reserve and the number of eggs available in a woman. This hormone analysis is usually carried out when a woman has problems in achieving pregnancy and goes to a fertility centre. A blood test to determine hormone levels is essential in the study of a woman's fertility.

However, any woman can undergo a blood test to check her condition and the number of eggs available at any given time.

Is it possible to achieve pregnancy with a diminished ovarian reserve?

By Zaira Salvador BSc, MSc (embryologist).

The probability of achieving a pregnancy naturally decreases as the ovarian reserve decreases. Assisted reproduction can overcome this obstacle, especially with ovarian stimulation techniques and in vitro fertilisation.

For the most severe cases, where the ovarian reserve is severely compromised, egg donation could be considered as a possible solution when it comes to having a child.

Suggested for you

We have talked about the blood test as a tool to know the number of eggs a woman has. There are other methods to know the state of your ovarian reserve that you can find here: What Can Ovarian Reserve & AMH Tests Tell Us?

Apart from those discussed in this article, there are other hormones related to female fertility. You can find out what they are and their normal values here: Female Hormone Check - How Are Hormone Levels Monitored?

Our editors have made great efforts to create this content for you. By sharing this post, you are helping us to keep ourselves motivated to work even harder.

References

C Peluso, F L A Fonseca, I F Rodart, V Cavalcanti, G Gastaldo, D M Christofolini, C P Barbosa, B Bianco. AMH: An ovarian reserve biomarker in assisted reproduction. Clin Chim Acta. 2014 Nov 1;437:175-82. doi: 10.1016/j.cca.2014.07.029.

F J Broekmans, J Kwee, D J Hendriks, B W Mol, C B Lambalk. A systematic review of tests predicting ovarian reserve and IVF outcome. Hum Reprod Update. Nov-Dec 2006;12(6):685-718. doi: 10.1093/humupd/dml034.

Matheus Roque, Marcello Valle, Marcos Sampaio, Selmo Geber, Miguel Angel Checa. Ratio of progesterone-to-number of follicles as a prognostic tool for in vitro fertilization cycles. J Assist Reprod Genet. 2015 Jun;32(6):951-7. doi: 10.1007/s10815-015-0487-1. Epub 2015 May 1.

Wenbin Wu, Xingling Wang, Yushan Li, Yuchao Zhang. Analysis of the women with the AMH concentrations below the limit of reference range but with the ideal number of retrieved oocytes. Arch Gynecol Obstet. 2020 Apr;301(4):1089-1094. doi: 10.1007/s00404-020-05491-9. Epub 2020 Mar 16.

FAQs from users: 'Can treatment delay the decline in ovarian reserve?', 'Is it possible to measure ovarian reserve with a home method?', 'What are the causes of diminished ovarian reserve?', 'How many eggs does a woman produce in adulthood?', 'At what age is it recommended to do a blood test to assess the number of eggs?' and 'Is it possible to achieve pregnancy with a diminished ovarian reserve?'.

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Authors and contributors

 Concha Leal Cariñena
Concha Leal Cariñena
Gynecologist
Bachelor's Degree in Medicine from the University of Zaragoza. She has an extensive career as a gynaecologist specialising in assisted reproduction and is also an associate lecturer in the Department of Surgery, Gynaecology and Obstetrics at the University of Zaragoza More information about Concha Leal Cariñena
License: 5008547
 Marta Barranquero Gómez
Marta Barranquero Gómez
Embryologist
Graduated in Biochemistry and Biomedical Sciences by the University of Valencia (UV) and specialized in Assisted Reproduction by the University of Alcalá de Henares (UAH) in collaboration with Ginefiv and in Clinical Genetics by the University of Alcalá de Henares (UAH). More information about Marta Barranquero Gómez
License: 3316-CV
 Zaira Salvador
Zaira Salvador
BSc, MSc
Embryologist
Bachelor's Degree in Biotechnology from the Technical University of Valencia (UPV). Biotechnology Degree from the National University of Ireland en Galway (NUIG) and embryologist specializing in Assisted Reproduction, with a Master's Degree in Biotechnology of Human Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI) More information about Zaira Salvador
License: 3185-CV

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