Urology Health - What is Vaginal Fusion and Duplication?


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What is Vaginal Fusion and Duplication?

Having two of everything is great when you’re talking about eyes, ears, hands and feet. In the female reproductive system, more than one (duplication) of certain organs — like the uterus, cervix, and vagina – is not so good. It is also not good when organs are joined (fusion) together.

What causes these rare cases?

The information here should help you learn what to do if your child's doctor finds an " anomaly of fusion and duplication."

How do genitalia normally form?

Sex organs form with three basic steps:

  1. The chromosomal sex is set when the sperm fertilizes the egg. An XX pair means that the baby is female. An XY pair means that the baby is male.
  2. Next, the gonads (sex glands) become either testis for a boy or ovaries for a girl.
  3. Then, the inner reproductive system, and outer genitals form. They grow with hormones from the testis or ovaries.

At conception, the mother gives an X chromosome and the father an X or Y chromosome. The combination forms either a female embryo (XX), or a male embryo (XY). At this point, the male and female embryos look the same.

Embryos start with two gonads. They can become either testes or ovaries. Each embryo also starts with both male and female inner genital structures. They become male OR female reproductive structures. For girls, very little change is needed for outer sex organs to look normal. The vagina develops right away, before the ovaries have fully formed.

All of these steps take place during the first three months of pregnancy. After that, the outer sex organs are formed. They look like those of a full-term girl or boy (apart from their size).

How do the female reproductive organs work?

There are several functions of the female reproductive system. The ovaries make the female egg cells, called the ova or oocytes. The oocytes are then transported to the fallopian tube where an egg may get fertilized by a sperm. The fertilized egg then moves to the uterus, where the uterine lining has thickened. The lining has thickened in response to the normal hormones of the reproductive cycle. The fertilized egg can implant into thickened uterine lining and continues to develop. If fertilization does not take place, the uterine lining is shed as menstrual flow.

In addition, the female reproductive system produces female sex hormones that maintain the reproductive cycle.

During menopause the female reproductive system slowly stops making the female hormones needed for the reproductive cycle to work. At this point, menstrual cycles can become irregular and will stop. One year after menstrual cycles stop, the woman is said to be menopausal.

The female reproductive anatomy includes both external and internal structures.

The function of the external female reproductive structures (the genital) is twofold: To enable sperm to enter the body and to protect the internal genital organs from infectious organisms. The main external structures of the female reproductive system include:

  • Labia Majora
  • Labia minora
  • Bartholin Glands
  • Clitoris

The internal female reproductive anatomy includes:

  • Vagina
  • Uterus (Womb)
  • Ovaries
  • Fallopian Tubes


Most of the female reproductive system comes from two structures, known as müllerian ducts. These ducts become the fallopian tubes, uterus and vagina in females.

They form into reproductive organs during the ninth week of pregnancy. In rare cases, the "fusion" or "duplication" of organs can occur. For example:

  • In uterus didelphys, there are two each of a uterus, cervix and vagina. One vagina is blocked, and the other is unblocked.
  • In uterus duplex bicollis, there are two uteruses and cervix, but only one vagina.
  • In bicornate uterus, there are two uteruses fused with one cervix and one vagina.


There may be no obvious signs. Sometimes the outer organs may not look normal.

In adult women, infertility is the main problem.

For a baby or young girl, early signs of this disease could be:

  • Urine pooling then leaking from the vagina during and after urinating
  • Frequent urinary tract infections (UTI)
  • A lump or mass in the lower belly
  • Discomfort with puberty


Some fusion abnormalities can be seen in newborns. Lumps in the lower belly, found with a physical exam may signal this problem. An ultrasound can show why a lump pushes the bladder forward and the vagina back.

Some patients with complete duplication and a block are found at puberty. A girl can get her period, but she will feel uncomfortable. At that time a lump in the lower belly can be seen. This lump is from the buildup of menstrual fluid in the blocked vagina.

If a physical exam doesn’t show a problem, an exam called a vaginoscopy may be done. For this exam, a scope is placed in the vagina to let the surgeon to see inside. Sometimes an MRI is used to get a full diagnosis.


Not everyone needs treatment. Each woman should be treated based on her well-being and pregnancy goals.

Surgery is needed to treat vaginal fusion and duplication when:

  • The condition is causing symptoms
  • A woman is unable to get pregnant
  • A woman has had miscarriages

Surgical treatment can allow a woman to have a healthy pregnancy. If there is complete duplication with a block, the urologist can surgically drain fluid. Other times, more involved surgery is needed.

After Treatment

After treatment, many women have no medical or pregnancy problems.

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