It is a protein hormone that is important in the development of the reproductive tract in a male fetus and is also produced (before birth) by the testes and ovaries.
About eight weeks after conception, the human fetus has two sets of ducts, one of which can develop into the male reproductive tract and the other into the female reproductive tract .
If the fetus is genetically male (XY chromosomes), the embryonic testes will produce antimullerian hormone.
This causes the Müllerian (female) ducts to disappear, hence the term anti-Müllerian hormone.
Whereas the testosterone produced by the testes makes the male (Wollfian) ducts survive.
The Wollfian ducts develop in the different parts of the male reproductive system: the epididymis, the vas deferens, the seminal vesicles and the prostate.
In a female fetus (XX chromosomes), the Wollfian ducts disappear (due to a lack of testosterone) and the Müllerian ducts develop into the female reproductive system.
Anti-Mullerian hormone may also play a role in regulating sex steroid production at puberty and in the adult ovaries and testes.
In the ovaries, antimullerian hormone appears to be important in the early stages of follicle development, which contain and maintain eggs prior to fertilization.
The more ovarian follicles a woman has, the more antimullerian hormone her ovaries can produce.
So the hormone can be measured in the bloodstream to determine how many follicles a woman has in her ovaries, that is, ovarian reserve.
When is a test necessary?
An antimullerian hormone test may be performed in women when evaluating ovarian function for fertility problems.
Especially when assisted reproductive procedures are considered and when a doctor seeks to determine the likelihood of a woman entering menopause.
Anti-Müllerian hormone can be applied when a woman has signs and symptoms of PCOS. Some of these include:
- Abnormal uterine bleeding
- Absence of menstrual cycle (amenorrhea).
- Decreased breast size.
- Enlarged ovaries
- Skin spots in the armpits or neck.
- Hair thinning
Periodically antimullerian hormone testing may be recommended to a woman with ovarian cancer to monitor the effectiveness of treatment and monitor for recurrence.
Testing may also be recommended when a baby has ambiguous genitalia or when a boy’s testicles have not descended properly.
Testing for anti-Müllerian hormone is not a routine test but may be helpful in specific circumstances.
It is a hormone produced by reproductive tissues. Its function and the amount normally present varies by sex and age.
Anti-Müllerian Hormone Test in Women
Women of childbearing age can request an anti-Müllerian hormone test along with other hormonal tests, such as estradiol, to estimate the time remaining to conceive.
These tests are also useful in evaluating ovarian function and possibly in predicting the onset of menopause.
The antimullerian hormone test can sometimes be performed for a woman who will undergo assisted reproductive procedures, such as invitro fertilization.
In invitro fertilization, the concentration of antimullerian hormone present is related to its probable capacity to respond to treatment.
A low level of antimullerian hormone reflects a poor ovarian response, indicating that fewer ovaries would recover after ovarian stimulation.
For this purpose, it is usually done in conjunction with other hormonal tests and a transvaginal ultrasound (to count the number of follicles as a reflection of the woman’s egg supply).
An anti-Müllerian hormone test can also be used to evaluate for polycystic ovarian syndrome.
The antimullerian hormone may be elevated due to the increase in the number of follicles present.
Some ovarian cancers produce higher levels of anti-Müllerian hormone.
If the hormone is initially elevated, then the test can be used as a tumor marker to help assess response to treatment and monitor for recurrence.
Anti-Müllerian Hormone Test in Babies
In a baby with external genitalia that are not clearly male or female (ambiguous genitalia), an anti-Müllerian hormone test may be applied.
This test is done in conjunction with chromosome tests, hormone tests, and sometimes image scans to help determine the baby’s gender.
In a boy born without visible testicles, low levels of anti-Müllerian hormone may explain the ambiguity of the genitalia.
If the testicles have not descended, but are present in the abdomen, this test can be used to help determine if they are working by measuring the level of anti-Müllerian hormone.
How is it controlled?
It is currently not known how the production of the anti-Müllerian hormone is controlled.
What does the test result mean?
During a woman’s childbearing years, a decrease in the level of anti-Müllerian hormone may indicate a low number and quality of eggs with decreased fertility.
This results in a minimal or less response to the invitro fertilization treatment.
It can also indicate that the ovaries are not working normally (premature ovarian failure).
A falling level and / or a significant decrease in anti-Müllerian hormone may indicate the imminent onset of menopause.
Negative levels of the hormone are normal in women during childhood and after menopause.
Increased antimullerian hormone may indicate an increased or even excessive responsiveness to invitro fertilization and the need to adapt the procedure accordingly.
When antimullerian hormone is used as a tool to control hormone-producing ovarian cancer, a decrease in it indicates a response to treatment, while an increase may indicate cancer recurrence.
In a male baby, the absence or low levels of the hormone may indicate a problem with the anti-Müllerian hormone gene located on chromosome 19.
This chromosome directs the production of the anti-Müllerian hormone and can be seen with absent or non-functional testes.
Lack of male hormones can lead to ambiguous genitalia and can cause abnormal internal reproductive structures.
Normal levels of antimullerian hormone and androgens in a male child whose testes have not descended indicate that they are present and functional, but not physically where they are supposed to be.
Increase or decrease in hormone
When the male fetus does not produce enough antimullerian hormone, the Müllerian ducts do not disappear and this leads to a persistent Müllerian duct syndrome.
Patients with this syndrome will have a masculine appearance, but usually have undescended testes (cryptorchidism) and low or no sperm count due to abnormal development of the Wollfian duct.
This can be associated with malformation of the vas deferens and epididymis. This condition is rare.
Since the ovarian follicles produce the hormone in adulthood, measuring the levels of the hormone in the blood provides a way to estimate ovarian reserve in women.
Consequently, hormone levels are routinely used to predict how well a woman will respond to ovarian stimulation for in vitro fertility treatment.
In women, anti-Müllerian hormone levels peak around puberty and remain relatively constant until after menopause.
So when there are no follicles left and anti-Müllerian hormone levels decrease.
Some studies suggest that anti-Müllerian hormone levels may be lower than normal in women experiencing premature ovarian failure.
However, antimullerian hormone results should be interpreted with caution as many other factors can affect an individual’s fertility.
High levels of antimullerian hormone can be associated with PCOS.
However, measuring antimullerian hormone can be misleading and does not provide a definitive diagnosis of premature ovarian failure or polycystic ovarian syndrome.
It is important that any test to measure anti-Müllerian hormone levels be performed by a qualified medical professional.
Should all women of childbearing age have an anti-Müllerian hormone test?
For most women, the anti-Müllerian hormone test is not considered necessary unless they have fertility problems.
Most women will not need this test.
While no test is perfect on its own or predicts with 100% accuracy what will happen in a woman’s body, the anti-Müllerian hormone test is being used more and more.
In endocrinology it is used to guide treatment options and calculate the probability of a woman’s pregnancy.