What is it with two uteruses?

There are many twins in life, and the probability of twins is very high. There are not only twins, but also triplets. This is not only because the number of fertilized eggs formed by human eggs and sperm is large, but also because people may have two uteruses, and some people have fraternal twins, which will cause a larger gap between the twins. So what's the matter with having two uteruses?

With the advancement of human medical technology, childbirth is no longer a sword hanging over the heads of most women. At the same time, multiple births are becoming more common.

The probability of this event happening is really too small. There are only 70 recorded cases of twin uterus pregnancies in the world. The probability of twin uterus each giving birth to a single baby is about 1/5 million, and the probability of twin uterus giving birth to triplets is as low as 1/25 million. Earlier in 1981, there were reports in Israel about a woman who had two uteruses and gave birth to three children. Unfortunately, one of the babies died in the womb, and the remaining two children were born in the 27th and 45th weeks of pregnancy respectively.

Compared to the low probability of having a pregnancy with two uteruses at the same time, the probability of having two uteruses at the same time like Hannah is much higher. The incidence of this condition, called uterus didelphys, is about 1 in 300, while the incidence of the more general condition of uterine septate is even higher.

So what exactly is this uterine septate?

Gently draw a dividing line, one uterus on the left and one on the right.

Before talking about uterine septum, let's first talk about the development process of the uterus.

During the early development of the human embryo, regardless of gender, it has two sets of primitive reproductive tracts. These two sets of reproductive tracts differentiate and degenerate separately to form different reproductive organs. Corresponding to the female reproductive organs is the development of the paramesonephrieduct (also known as the Mullerian duct).

Simply put, the paramesonephric ducts are like two plastic tubes. At the beginning, the two tubes are independent of each other, and then the lower parts of the tubes are close together, forming a "Y" shape. Then the parts close together at the lower ends gradually grow and fuse into one, and this part develops into the uterus.

Uterine septum is an abnormality caused by obstacles encountered during the fusion of the paramesonephric ducts.

Uterine septate can be roughly divided into three types: didelphys, bicornuate uterus and uterus septum.

A double uterus refers to a condition in which the lower ends of the paramesonephric ducts, which should have been fused, are not fused at all, and they independently differentiate into two uterine bodies and cervixes. Since the fallopian tubes also develop from the paramesonephric ducts, each uterus of a patient with double uterus is connected to a fallopian tube and ovary.

The fusion abnormality of the bicornuate uterus occurs at the bottom of the uterus, where the area that should be filled appears concave. Milder cases are also called saddle-form uterus or arcuate uterus.

The septate uterus is caused by incomplete fusion, and the septate uterus is divided into incomplete septate uterus and complete septate uterus. As the name suggests, an incompletely septate uterus means that the uterus is not completely separated, and the remaining part in the middle divides the space inside the uterus into a "V" shape; while the uterus of a completely septate uterus presents a "Ⅱ" shape.