What are the effects of abnormal uterine development?

The uterus is a special physiological organ of women. It can be said that only women with healthy uteruses are fertile, while some women with abnormal uterine development are actually infertile. Uterine abnormalities can be divided into congenital uterine abnormalities and acquired uterine abnormalities. In short, uterine abnormalities are a very painful thing for women.

So what are the symptoms of abnormal uterine development? What impact will abnormal uterine development have on the patient's life? Let us learn about it together.

1. Congenital absence of uterus or uterine hypoplasia:

The latter refers to the different immature stages of uterine development from the fetal period to pre-pubertal period.

1. Congenital absence of uterus: The paramesonephric ducts on both sides extend horizontally toward the midline and merge. If they stop developing before reaching the midline, no uterus will be formed. Congenital absence of the uterus is often combined with congenital absence of the vagina, but there may be normal fallopian tubes and ovaries. During rectal examination, the uterus cannot be touched at the area equivalent to the cervix and uterine body, but only the peritoneal folds can be felt.

2. Primitive uterus: If the two mesonephric ducts on both sides extend horizontally to the midline and meet and then stop developing shortly after that, this type of uterus is very small, usually without a uterine cavity or with a uterine cavity but without endometrial growth, and therefore no menstruation.

3. Immature uterus: In the late pregnancy or any period after the birth of the fetus and before puberty, the uterus stops developing and various degrees of uterine hypoplasia may occur. The cervix of this type of uterus is relatively long, mostly conical, with a small external os; the uterine body is smaller than normal and often extremely anteverted or retroverted. Those with anteroflexion often have underdeveloped anterior uterine wall, while those with retroflexion often have underdeveloped posterior uterine wall. An immature uterus can cause dysmenorrhea, oligomenorrhea, amenorrhea or infertility.

(ii) The junction of the two paramesonephric ducts is blocked:

This type is the most common and has important clinical significance. Due to the different periods and degrees of obstruction of the conjunction, the following manifestations may occur:

1. Unicornuate uterus: One side of the mesonephric duct is well developed, forming a well-developed unicornuate uterus with a normally developed fallopian tube. The development of the contralateral paramesonephric duct completely stops. A unicornuate uterus may function normally. If pregnancy occurs, the pregnancy and delivery process may be normal, but it may also cause miscarriage or dystocia.

2. Rudimentary horn of uterus: The paramesonephric duct on one side develops normally, but the other side experiences abnormal conditions such as stagnation during development, resulting in a rudimentary horn of the uterus to varying degrees. Most of them are only connected to the unicornuate uterus on the opposite side through fiber bundles. Since the endometrium is mostly non-functional, there are often no symptoms. If it is functional, symptoms of menstrual blood retention such as periodic lower abdominal pain will appear after puberty. Some of them are connected to the opposite uterus by a narrow cavity. In this case, a rudimentary horn pregnancy may occur. The symptoms are the same as those of an interstitial tubal pregnancy. It often ruptures at 3 to 4 months of pregnancy, causing severe internal bleeding.

3. Blind horn uterus: The paramesonephric ducts on both sides are well developed, but one uterine horn does not communicate with the vagina, forming a blind horn uterus. After puberty, menstruation comes with periodic lower abdominal pain, which becomes increasingly severe and goes undetected for a long time. Retention of menstrual blood can cause uterine blood accumulation, blood accumulation in the fallopian tube, and even menstrual blood can flow into the abdominal cavity through the opening of the fallopian tube fimbria. An enlarging mass may be felt in the lower abdomen. Some blind horn uteri have an incompletely developed vagina, but it is not connected to the normal vagina. After the formation of colpostomy, it can be misdiagnosed as a vaginal cyst. Treatment: Through corrective surgery, the blind angle of the uterus is connected with the opposite uterine cavity or vaginal cavity.

4. Double uterus and duplicate uterus (symmetrical type): These two deformities are very similar. The former is because the paramesonephric ducts do not merge at all after development, and each has its own set of fallopian tubes, uterus, cervix and vagina. This situation is relatively rare. The latter is also called double-horned and double-cervical uterus, in which the paramesonephric ducts are completely fused, but the septum is completely unabsorbed. The only difference between the two is that the space between the two uteri in the former is wider than that in the latter. Uterus didelphys may or may not have a vaginal septum.

5. Bicornuate uterus: The tail ends of the paramesonephric ducts on both sides have largely merged, and the terminal septum has been absorbed, so there is one cervix and one vagina; but it is equivalent to incomplete fusion of the fundus of the uterus, resulting in a protruding horn on each side of the uterus, which is called a bicornuate uterus. If the degree of this type of deformity is milder, the fundus of the uterus is sunken inward. Depending on the degree, it may form a so-called saddle-shaped uterus, heart-shaped uterus, or arcuate uterus. If pregnancy occurs, it may cause miscarriage or abnormal fetal position.

6. Septate uterus: After the two mesonephric ducts merge, the mediastinum is not absorbed and divides the uterine body into two halves, but the appearance of the uterus is completely normal. Sometimes the mediastinum is incomplete, resulting in a small channel between the two separate uteruses and cervixes, so it is called a communicating uterus. It is often accompanied by vaginal septum, and the channel is often located in the isthmus of the uterus. Sometimes one side of the vagina is partially blocked, and the retained menstrual blood can slowly flow out through the isthmus to the unobstructed vagina on the other side. Therefore, patients may seek medical treatment because of frequent discharge of old bloody secretions from the vagina.

7. Saddle-shaped uterus: The fundus of the uterus is concave, with varying degrees of depression.

(III) The ducts are not connected after the paramesonephric ducts merge:

The part of the uterus formed after the paramesonephric ducts merge, part or all of which do not penetrate to form a solid uterus, and there is no endometrium. This type of uterus looks similar to a normal uterus except that it is smaller, but there is no menstruation.

(IV) Congenital ectopic uterus:

The uterus or one of the uteruses may be displaced into an inguinal hernia, as may the ovaries or fallopian tubes. The uterus may also remain in its higher embryonic position without descending into the pelvic cavity.

Uterine prolapse can occasionally be seen in various periods after birth, often coexisting with spina bifida and often accompanied by pelvic floor muscle hypoplasia.

(V) Iatrogenic congenital uterine anomaly:

Congenital uterine anomalies may occur in some patients with dysplasia of the paramesonephric duct and diethylstilbestrol syndrome. Among patients who were affected by diethylstilbestrol during intrauterine development, resulting in diethylstilbestrol syndrome or vaginal epithelial changes, 82% had abnormal findings on hysterosalpingography. These abnormalities include uterine hypoplasia or uterine enlargement, T-shaped or arcuate uterus, the presence of fibromuscular narrowing bands or uterine horns in the uterine cavity, narrowing of any part of the uterus or relatively wide lower uterine segment, irregular uterine cavity edges or polypoid lesions, and intrauterine adhesions.

2. Clinical manifestations of uterine dysplasia:

Some patients with uterine malformation may not have any conscious symptoms, and there are no abnormal manifestations in menstruation, sexual life, pregnancy, and childbirth, so they may not be discovered throughout their lives, or may be discovered occasionally during a physical examination. However, the reproductive system function of some patients is affected to varying degrees, and the disease is not discovered until the onset of symptoms during sexual maturity, after marriage, pregnancy, or delivery.

(1) Abnormal menstruation:

Patients with congenital absence of uterus or primordial uterus have no menstruation. Patients with immature uterus may have no menstruation, or may have symptoms such as scanty menstruation, delayed menstruation, dysmenorrhea, and irregular menstruation; patients with double uterus or bicornuate uterus often have excessive menstrual flow and prolonged menstrual duration.

(ii) Infertility:

Uterine hypoplasia, such as absence of uterus, primordial uterus, and infantile uterus, is often one of the main causes of infertility.

(III) Pathological pregnancy:

An abnormally developed uterus often causes miscarriage, premature birth or abnormal fetal position after pregnancy. Spontaneous uterine rupture during pregnancy may occasionally occur. If the fallopian tube of the rudimentary uterine horn is unobstructed, the fertilized egg can implant in the rudimentary horn of the uterus. However, due to the poor development of the uterine muscle layer, it often ruptures during pregnancy, and the symptoms are the same as those of ectopic pregnancy.

(IV) Pathology during and after delivery:

A malformed uterus often coexists with myometrial dysplasia. During delivery, abnormal labor force and difficulty in cervical dilation may lead to difficult labor or even uterine rupture. Vaginal delivery may result in retained placenta, postpartum hemorrhage, or postpartum infection. After a patient with double uterus becomes pregnant, the pregnant uterus grows and develops, and if the non-pregnant uterus is located in the rectouterine fossa, it may cause obstructive dystocia during delivery. Patients with double uterus, bicornuate uterus or septate uterus may experience bleeding after delivery due to the discharge of decidua from the non-pregnant side of the uterine cavity.

The uterus can be said to be the place where women's hopes of becoming mothers come true and where new life is nurtured. Abnormal uterine development is very harmful to women. Therefore, if you find symptoms of uterine abnormalities in daily life, you must seek medical attention in time to reduce the harm of uterine abnormalities to the patient's body and mind.