Müllerian Ducts

What are the Müllerian ducts?

The Müllerian ducts are paired tubes that develop into the female reproductive organs. This happens while a fetus is growing in the womb.

Both males and females have Müllerian ducts at first. But during sexual differentiation (development of female or male sex organs), that changes. If a male hormone called anti-Müllerian hormone (AMH) is present, it prevents the ducts from developing into female sex organs. The Müllerian ducts are also called the paramesonephric ducts.

What is the purpose of the Müllerian ducts?

The function of the Müllerian ducts is to develop into the female reproductive system organs. These organs are necessary for a person to carry a pregnancy. The organs include:

• Upper section of the vagina.
• Cervix (lower portion of the uterus).
• Uterus (organ that houses a developing fetus).
• Fallopian tubes (carry eggs from the ovaries to the uterus).

What’s the difference between the Müllerian ducts and the Wolffian ducts?

The Wolffian ducts — also called the mesonephric ducts — eventually develop into the male reproductive organs. Females have Wolffian ducts, too, but they return to a less developed state. The Wolffian ducts develop into the:

• Seminal vesicles (glands that produce semen).
• Vas deferens (tubes that carry sperm).
• Epididymis (tube that stores sperm).

Where are the Müllerian ducts located?

The Müllerian ducts start developing on top of an embryo’s kidneys (mesonephric kidneys) about 3–4 weeks into gestation (fetal development). These early kidneys are temporary kidneys. They’re eventually replaced with fully functioning kidneys around 32 weeks into gestation.

How do the Müllerian ducts develop?

While the Müllerian ducts gradually grow on the mesonephric kidneys, cells develop. These cells will form the different layers of the ducts. The layers thicken and grow downward into a long, finger-like projection. Between 8–12 weeks into gestation, the tip of the Müllerian ducts fuses with the Wolffian ducts. Then they start to form the beginning of sex organs.

What are Müllerian ducts made of?

Müllerian ducts contain epithelial and mesenchymal cells. Epithelial cells line a lot of organs. They help protect organs and also absorb and release important substances. Mesenchymal cells are stem cells, so they can grow into different types of cells.

What conditions and disorders affect the Müllerian ducts?

Most Müllerian duct anomalies (abnormalities) happen because the ducts don’t develop correctly in the womb. As a result, Müllerian duct problems are usually congenital (present at birth), even though they might not get diagnosed until adulthood. Signs of Müllerian duct problems may include female infertility.

Some Müllerian duct defects include:

• Müllerian agenesis or hypoplasia: The uterus is missing (agenesis) or underdeveloped (hypoplasia). Less often, the fallopian tubes are missing or underdeveloped. The most common form of uterine agenesis is Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome, which causes uterine factor infertility. An abnormal gene causes MRKH.
• Vaginal septum: If the Müllerian ducts don’t fuse together correctly as they develop, tissue might form a septum in the vagina. The tissue may completely or partially block the vagina. It can also divide the vaginal canal into two canals.
• Persistent Müllerian duct syndrome (PMDS): Some males have a genetic disorder that prevents the secretion of the AMH. They have normal male reproductive organs, but they also develop a uterus and fallopian tubes. Males with PMDS may also have undescended testicles or inguinal hernias.
• Uterine abnormalities: Problems with Müllerian duct development can cause deformities. These may include a partial horn-shaped uterus, a double uterus, a uterus divided in half by a wall of tissue, a T-shaped uterus or an indented uterus.

People with Müllerian duct anomalies may also have kidney problems. This happens because the ducts and kidneys develop near each other. If pieces of the Müllerian or Wolffian ducts stay in the vagina after birth, vaginal cysts may develop.

How common are Müllerian duct anomalies?

Müllerian duct anomalies are quite rare. They’re present in only 0.1% to 3.0% of live births.

What questions should I ask my doctor about Müllerian duct anomalies?

If you or your child has a Müllerian duct defect, consider asking your healthcare provider the following questions:

• Can it affect fertility?
• Does it affect hormones?
• What treatments are available?
• Will puberty and menstruation be normal?

I’m pregnant or planning to be pregnant. How can I prevent Müllerian duct anomalies?

There’s no way to completely prevent Müllerian duct anomalies. They’re usually the result of a problem with a gene or a random developmental defect. But you can stay as healthy as possible before and during pregnancy to reduce the risk of birth defects.

Health tips include:

• Avoid illegal drugs and marijuana.
• Don’t smoke or drink alcohol.
• Get proper prenatal care.
• Manage chronic health conditions.
• Take prenatal vitamins with folic acid.
• Maintain a healthy weight.
• Exercise regularly and eat a well-balanced diet.

A note from Cleveland Clinic

The Müllerian ducts are paired tubes. They develop into female reproductive organs during fetal development. If the ducts don’t develop properly, a baby might be born with abnormal anatomy. These abnormalities may affect the uterus, cervix, fallopian tubes and/or vagina. Many Müllerian duct anomalies aren’t diagnosed until menstruation begins or until trying to conceive.