The endometrium is the mucosa that lines the inside of the uterine wall. The endometrium is the implantation site of the embryo in the uterus. It can therefore be said that the endometrium is the key tissue for the maintenance of pregnancy. During pregnancy, there are a number of changes in the structure and function of the endometrium. Endometrial diseases can make it difficult to get pregnant, and sometimes also make it impossible to report it. What functions does the endometrium perform during pregnancy? How does the endometrium change during pregnancy? Which endometrial diseases can affect pregnancy?
The endometriumis a type of tissue, or more precisely, the mucosa that lines the inside of the uterine cavity. The endometrium is therefore the innermost layer of the uterine wall. The structure of the endometrium, and above all its thickness, is regulated by the activity of hormones. The endometrium looks different in pre-pubertal girls than in women of childbearing age and still different in postmenopausal women. The structure of the endometrium in women during the reproductive period changes during the menstrual cycle.
Endometrium - structure and functions
There are two layers within the endometrium:
- primary
- and functional.
The basal layer is the "base" of the endometrium, which does not undergo any significant changes over the course of the monthly cycle. The second layer of the endometrium - functional - undergoes periodic reconstruction under the influence of sex hormones.
In the follicular phaseof the cycle, under the influence of estrogens, the endometrium thickens and its vessels grow.
In the luteal phasethe endometrium prepares for fertilization and implantation of the embryo. Under the influence of progesterone, the endometrium builds up and accumulates spare substances.
If fertilization is not achieved during the cycle, the functional layer of the endometrium peels off. There is menstrual bleeding and the next menstrual cycle starts.
How is the structure of the endometrium assessed?
The test that enables precise imaging of this tissue is transvaginal ultrasound. Typically, an ultrasound examination is performed in the first phase of the cycle, after the end of menstruation.
In transvaginal ultrasound, you can measure the thickness of the endometrium, assess its structure and homogeneity. Normal endometrium in the first phase of the cycle should not exceed 10 mm, and in the second phase - 15 mm. .
The endometrium is much thinner in pre-pubescent girls (less than 1mm)andin postmenopausal women (less than 5mm) .
Appropriate thickness and preparation of the endometrium are a necessary condition for the implantation of the embryo, i.e. its implantation in the uterine wall.
Too thin endometrium and changes in the structure of the endometrium (e.g. polyps) may make it difficult or even impossible to get pregnant. Similar problems can be caused by endometriosis, a disease associated with the presence of the endometrium in abnormal locations outside the uterine cavity.
Endometriosis is believed to be one of the most common causes of infertility among women. For this reason, endometrial assessment is one of the first steps in the diagnosis of causes of infertility.
The role of the endometrium in pregnancy
Cyclical changes of the endometrium along with the course of the menstrual cycle are designed to prepare it to fulfill the most important role - to support pregnancy. Properly prepared endometrium may become a place of embryo implantation, i.e. implantation.
Embryo implantation into the endometrium takes place a few days (usually 8-12) after conception. The implantation takes place during the so-called "Implantation window", i.e. the period when the endometrium is ready to receive the embryo.
The endometrium prepared for implantation is significantly thickened and bloodshot. Then it is calledtemporal membrane(temporal). As pregnancy develops, it is involved in the formation of the placenta, the organ that connects the mother and the fetus.
The temporal building of the maternal part of the placenta has many important functions. Through it, the fetus receives oxygen and nutrients necessary for life. The placenta also allows the removal of harmful and unnecessary metabolic products from the body of the fetus.
In addition to forming the placenta, a remodeled endometrium has other tasks in pregnancy. One of them is the production of hormones that enable the development and maintenance of pregnancy.
The endometrium also plays an important role in the immune system during pregnancy. Even though the fetus developing in the womb is a foreign organism, the mother's immune system does not seek to combat it.
The so-called immune tolerance, i.e. the suppression of the immune system's reaction against the cells of the fetus, is the result of an appropriately altered activity of the endometrium.
Endometrial diseases and pregnancy
The endometrium is a nesting sitethe embryo in the uterus. A properly functioning endometrium is essential for the maintenance of pregnancy.
Endometrial diseases may make implantation of the embryo impossible, or make it difficult to report pregnancy .
Some endometrial diseases can cause early miscarriages. Most endometrial diseases can affect the course of pregnancy. For this reason, the diagnosis and treatment of endometrial diseases can be a key condition for embryo implantation and subsequent pregnancy maintenance.
Endometrial atrophy and pregnancy
Endometrial atrophy is a state of endometrial cell atrophy, which leads to a decrease in its thickness. Natural endometrial atrophy occurs in postmenopausal women, when the endometrium ceases to undergo cyclical hormonal changes.
Endometrial atrophy may also appear in women of childbearing age and then it is a pathological condition. Too thin endometrium cannot properly prepare for embryo implantation, which may cause infertility.
Hormonal disorders are the most common causes of endometrial atrophy. Too low activity of estrogens or insensitivity to them may cause a significant reduction in the thickness of the endometrium.
Endometrial atrophy can also be a consequence of chronic inflammation. Recognition of the cause of endometrial atrophy increases the chances of its effective treatment, which is most often based on the use of appropriate hormonal preparations.
Endometrial hyperplasia and pregnancy
The opposite state to endometrial atrophy is its hypertrophy, i.e. excessive thickening.Endometrial hyperplasia is most often the result of hormonal imbalance- the predominant effect of estrogens and the reduction of the opposite activity of progesterone.
This condition may be the result of taking medications containing estrogen, but also other diseases (obesity, polycystic ovary syndrome).
Endometrial hyperplasia and the accompanying hormonal disruptions may make it difficult to become pregnantand therefore require appropriate treatment. If endometrial hyperplasia is diagnosed, it is also necessary to exclude neoplastic processes.
Although endometrial hyperplasia is usually benign and resolves with treatment, in some patients it may increase the risk of developing cancer.
In so-called atypical endometrial hyperplasia, cells are present in the uterus that can develop into cancerous cells . This variant of endometrial hyperplasia requires more aggressive treatment. Fortunately, it is relatively rare in women of childbearing age.
Endometrial inflammation and pregnancy
Endometrial inflammation is usually caused by the so-called ascending infection , that is, from the side of the vagina towards the distal parts of the reproductive system. Endometritis is most often of a bacterial etiology.
Inflammation of the endometrium may be seen as lower abdominal pain, abnormal bleeding or a fever. In some cases, endometritis may be asymptomatic.
Inflammation of the endometrium most often develops after gynecological procedures. Endometritis should not be taken lightly, as if left untreated, it can cause adhesions to form in the uterus, ovaries, and fallopian tubes.
These, in turn, can become a cause of infertility. Endometrial inflammation requires properly selected antibiotic therapy. In many cases, microbiological tests are also necessary to identify the causative organism.
Endometrial defects and pregnancy
Abnormalities in the structure of the endometrium may be congenital or acquired. Some of them cause pain or abnormal bleeding, others may remain completely asymptomatic.
Defects in the structure of the endometrium may prevent the embryo implanting in the uterine wall . The most common abnormalities in the structure of the endometrium includepolyps , i.e. pedunculated projections of the endometrium.
Endometrial polyps can reach different sizes. The largest of them often require surgical removal.
Another defect in the structure of the endometrium that can make it difficult to get pregnant isadhesions . Adhesions are abnormal connections between various parts of the endometrium, most often resulting from inflammatory processes or surgeries performed within the uterus.
An extreme example of a condition associated with the presence of adhesions in the uterine cavity is Asherman's syndrome, which is a rare cause of infertility. In Asherman's syndrome, the uterine cavity is partially or completely overgrown.
The most common cause of Asherman's syndrome is too deep curettage of the uterine cavity, leading to significant damage to the mucosa.
Asherman syndrome can make it difficult to conceive. Surgical treatment of Asherman's syndrome is effective in some patients, although unfortunately in some of them the adhesions may recur.
Endometriosis and pregnancy
Endometriosis is a condition where endometrial lesions are present outside the uterine cavity. An abnormally positioned endometrium can be found in the ovaries, fallopian tubes, and other parts of the pelvis and cavity.abdominal.
Endometriosis is believed to be the cause of up to 1/3 of all infertility cases . The impact of endometriosis on fertility is due to changes in the anatomy of the reproductive system.
Endometriosis outbreaks cause adhesions that can lead, among others, to to obstruction of the fallopian tubes. Additionally, endometriosis can disrupt the hormonal balance.
Getting pregnant in patients with endometriosis is difficult, but not impossible. The management of such patients is always individual, depending, among others, on on the stage of endometriosis and the length of efforts to get pregnant.
Advanced endometriosis may require surgery . For many patients with endometriosis, assisted reproductive techniques (ART) increase the chances of becoming pregnant.
- Endometrium (endometrium): functions and structure. Endometrial diseases
- Uterine defects: two-horned, one-horned, septal, arched and double uterus