The role of AMH in female reproduction
Before we talk about what antimüllerian hormone (AMH) is and what its role is in female reproduction, it is important to understand the basics of female fertility.
As early as the 3rd month of pregnancy in the womb of the mother of each woman, numerous small follicles are created in the womb of the mother, which will provide the eggs for her fertile life. Each woman is thus born with a certain number of eggs (about 1-2 million at birth), which gradually decreases throughout her life, so that at puberty the number of follicles in the ovaries does not exceed 400,000.
Starting with the first menstrual period, the body recruits a group of follicles (each with a small immature egg inside) that have the potential to respond to hormones, grow and ovulate. Usually, however, we have one ovulating egg each month. The remaining eggs that are not selected for ovulation will be “destroyed” and the process is repeated every month. So over the years many of the eggs degenerate and are destroyed.
In recent years there has been an increase in the average age of women interested in having a child.
Considering that fertility decreases as a woman gets older, since, as we said, the number of available follicles decreases over the years, it is important for expectant mothers to understand what is going on with their fertility and possibly what they can and cannot do with current treatments.
Only when women are armed with all the knowledge will they be able to make informed decisions about their health and their future!
What is AMH and what exactly do we measure?
AMH is a hormone produced by the small follicles in the ovaries. Measuring this hormone helps fertility doctors assess a woman’s ovarian reserve (i.e. whether there are sufficient remaining follicles inside the ovaries).
It is therefore an indirect indicator of the amount of eggs available.
The advantage of measuring AMH is that its levels are fairly stable and it can be measured on any day of a woman’s cycle. However, caution should be taken that AMH should be assessed in women with fertility problems and not in the general population, as there is no correlation between AMH and pregnancy probability. High AMH values (greater than 1.2ng/mL) usually indicate that a woman has normal ovarian reserve, while lower values (less than 1.2ng/mL) indicate that a woman has a reduced reserve.
Since AMH therefore indicates the number of available eggs, as expected, it decreases with age.
What AMH is NOT
- The measurement of AMH alone is not an indicator of a woman’s reproductive capacity.
It is also necessary to assess the values of the reproductive hormones FSH and LH, as well as the combined ultrasound examination, in order to estimate the number of small-sized follicles (AFC, antral follicular count), which is a basic indicator of the stock of primordial follicles available to each woman. - AMH cannot predict whether a woman can become pregnant.
One large study showed that there was no difference in pregnancy rates in women with normal AMH levels trying to conceive versus women with low levels of AMH (less than 1 ng/mL). - Just because a woman has “normal” AMH levels in the present does not mean that they will remain normal in the future. All women have a decline in fertility (hence AMH) as they age and how quickly this decline will occur is different for each woman and cannot be predicted.
AMH levels and IVF
Women with higher AMH levels have a better response to ovarian stimulation during in vitro fertilisation (IVF), as more eggs are developed and retrieved. On the other hand, women with low AMH have a lower number of follicles and produce fewer eggs.
By having more eggs in IVF, a greater number of eggs are given the opportunity to fertilise and develop into embryos. Therefore, a good AMH value is also associated with a better prognosis.
In addition, the concentration of AMH, in combination with the measurements of reproductive hormones and ultrasound imaging, before the start of each stimulation, gives a more complete picture, so that reproductive doctors can decide which stimulation protocol is the most appropriate for each woman, targeting a greater number and better quality of eggs and therefore embryos with higher chances of implantation and pregnancy.
How can we increase AMH levels?
Unfortunately, there are no scientifically proven ways to increase AMH levels.
What can we do?
It must be remembered that AMH shows us what the ovarian reserve is and the drop in the value of AMH is a normal mechanism with age.
A satisfactory or normal AMH measurement cannot predict how quickly it will decrease in the future and it also cannot predict whether a woman will be able to achieve spontaneous conception or the likelihood of achieving pregnancy in general.
Fertility specialists use the measurement of AMH as a diagnostic tool for an individualized approach to each woman.
On the other hand, childbearing at older ages is a reality. Modern techniques give every woman the option of postponing motherhood since they can cryopreserve and preserve their genetic material by successfully cryopreserving unfertilised eggs.
This gives each woman autonomy over if, when and how they become mothers.
