{"id":3527,"date":"2021-07-27T13:16:18","date_gmt":"2021-07-27T10:16:18","guid":{"rendered":"https:\/\/f-genetics.com\/?post_type=test&p=3527"},"modified":"2026-02-27T15:32:59","modified_gmt":"2026-02-27T12:32:59","slug":"molekulyarno-geneticheskoe-issledovanie-abortivnogo-materiala-na-hromosomnye-anomalii","status":"publish","type":"test","link":"https:\/\/f-genetics.com\/en\/molekulyarno-geneticheskoe-issledovanie-abortivnogo-materiala-na-hromosomnye-anomalii\/","title":{"rendered":"In case of a non-developing pregnancy"},"content":{"rendered":"

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Overview<\/div>
Chromosomal abnormalities<\/div>
Indications<\/div>
How it works<\/div>
What the result says<\/div><\/div><\/div>
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Many women experience pregnancy loss. Approximately one in five pregnancies ends in non-developement, spontaneous miscarriage, or stillbirth. More than half of all pregnancy losses are due to chromosomal abnormalities in the embryo. Most often such disorders occur by chance and do not recur in subsequent pregnancies.<\/p>\n\n\n\n

Understanding the cause of pregnancy loss helps to assess the risks of recurrence and determine tactics to prepare for the next pregnancy.<\/p>\n\n\n\n

Molecular genetic testing reveals chromosomal abnormalities and\u00a0allows us to understand whether pregnancy loss was an accidental event<\/strong> or whether a more detailed examination of the woman is needed to find the cause.<\/p>\n\n\n\n

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Chromosomal abnormalities<\/h3>\n\n\n\n
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Approximately half of all early pregnancy losses are due to an error that occurs during the formation of germ cells or at the time of fertilization. As a result of such an error, the embryo receives an abnormal number of chromosomes. This is called a chromosomal abnormality. Usually, chromosomal abnormalities occur by accident. <\/strong>This means that pregnancy loss is not caused by a woman doing something wrong.<\/strong><\/p>\n<\/div>\n\n\n\n

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Unfortunately, it is impossible to predict or prevent such an event.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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Sometimes chromosomal abnormalities can be inherited from parents and lead to repeated pregnancy losses in a couple. This happens when one partner has part of one chromosome attached to the other chromosome. This is called a balanced chromosomal translocation. People with a chromosomal translocation usually have no physical signs or symptoms, but when germ cells (eggs or sperm cells) are formed, some of them have abnormal chromosomes. If an embryo is formed from such germ cells, a chromosomal disorder occurs.<\/p>\n<\/div>\n\n\n\n

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Chromosomes are structures found in body cells that contain the genes that determine a person's physical state.<\/h3>\n\n\n\n
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Normal cells<\/strong> contain 46 chromosomes (23 pairs)<\/p>\n\n\n\n

Germ cells<\/strong> contain 23 chromosomes<\/p>\n<\/div>\n\n\n\n

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However, quite often during the formation of germ cells, chromosomes are distributed incorrectly, and the cell may contain not 23 chromosomes, but, for example, 24.<\/p>\n\n\n\n

During fertilization, when the egg and sperm fuse together, the two sets of chromosomes are combined. If an egg or sperm cell carries the wrong number of chromosomes, the chromosome set of the embryo will also be abnormal.<\/p>\n\n\n\n

Depending on how much the chromosomal set differs from normal, three outcomes are possible:<\/p>\n\n\n\n

1. The embryo stops developing before pregnancy occurs. Pregnancy does not occur.<\/p>\n\n\n\n

2. The pregnancy occurs, but the embryo develops abnormally. This leads to pregnancy loss.<\/p>\n\n\n\n

3. A child is born with a chromosomal syndrome - a severe incurable disease, such as Down syndrome, Edwards syndrome or Patau syndrome.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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Chromosomal abnormalities in fetal tissues can occur in women of any age, in any health condition and lifestyle, but the risk of such abnormalities increases significantly with the age of the woman. The risk of spontaneous miscarriage by age:<\/p>\n\n\n\n

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  1. 9-17% from 20 to 30 years old,<\/li>\n\n\n\n
  2. 20% at age 35,<\/li>\n\n\n\n
  3. 40% at age 40,<\/li>\n\n\n\n
  4. 80% at age 45.<\/li>\n<\/ol>\n<\/div>\n\n\n\n
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    Indications<\/h3>\n\n\n\n

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    About half of the cases of pregnancy loss in the first trimester are caused by a chromosomal abnormality. Therefore, the test is most relevant for early pregnancy loss. In later pregnancy, chromosomal abnormalities usually result in multiple malformations. If there are no malformations, it is unlikely that the test will reveal a chromosomal abnormality. Therefore, the test is more informative when the obstetrician-gynecologist suspects chromosomal abnormalities in the fetus.<\/p>\n\n\n\n

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    The test will help you understand the cause of pregnancy loss,which will increase your chances of preventing a loss next time. The results of the test should be discussed with your doctor. The test will be most relevant in specific cases:<\/p>\n\n\n\n

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    1. Termination of pregnancy for medical reasons when multiple fetal malformations are detected;<\/li>\n\n\n\n
    2. Repeated pregnancy loss, especially if no testing was done after the previous occurrence.<\/li>\n<\/ol>\n<\/div>\n\n\n\n
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      How it works<\/h3>\n\n\n\n

      Molecular genetic testing of aborted material for chromosomal abnormalities is a medical service performed in our laboratory on the registered F-Genetics platform using the Reproline kit.<\/p>\n\n\n\n

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      During the testing process, we select fetal tissue fragments from the aborted material. We wash them from the maternal cells and isolate a DNA<\/span> sample, which we prepare for\u00a0sequencing<\/span>. We then examine the sample using NGS<\/span> technology. The whole genome <\/span>is read; that is, the test affects the entire chromosome<\/span>, not just parts of it. Thanks to this technology, we can see if any chromosome or its fragment is too small or too large.<\/p>\n\n\n\n

      We look for chromosomal abnormalities in the sequencing results<\/strong>. If there are segmental abnormalities (changes in the number of copies of a fragment of a chromosome rather than a whole chromosome), we evaluate such an occurance in terms of its significance for the course of the pregnancy. We only include in the test report significant occurrences that may have influenced the non-developement of the pregnancy.<\/p>\n\n\n\n

      To search for chromosomal abnormalities, it is important to examine fetal DNA. But in the aborted material it can mix with the mother's DNA, and this distorts the result. If we have doubts about the purity of a sample of fetal DNA, we do additional testing and see if there is an admixture of maternal DNA. During the test, we\u00a0compare the DNA in the sample to DNA from the mother's blood<\/strong>. You can read more about the testing technology in the Paternity sections \"How it works\" tab<\/a>.<\/p>\n\n\n\n

      If the DNA of the embryo and the mother are mixed, we take a new batch of embryonic tissue and repeat the test all over again. In some cases (about 5% of samples), the biological material received by the laboratory does not contain embryonic tissue, but only maternal one. In this case, the analysis cannot be performed, and the laboratory will refund the money.  <\/p>\n\n\n\n

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      What the result says<\/h3>\n\n\n\n
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      As a result of the test you will receive data on the chromosome set in the embryo cells: whether it is normal, and if not \u2014 how exactly it differs from the norm. <\/p>\n\n\n\n

      For correct interpretation of the result and understanding of further actions we recommend consult with a geneticist<\/a>.<\/p>\n\n\n

      The doctor will conclude whether the pregnancy loss was an accidental event and tell you about the individual risks of repeated pregnancy loss. In some cases, the doctor may recommend karyotyping of the couple. This test determines the number and structure of chromosomes. Karyotyping may reveal balanced chromosomal translocation<\/span> in either parent, a possible cause of repeated miscarriages.<\/p>\n\n\n\n

      If a chromosomal translocation is detected, the geneticist may suggest in vitro fertilization (IVF) with special genetic testing \u2014 preimplantation genetic testing for aneuploidy (PGT-A)<\/a>. This method allows an embryo with a normal number of chromosomes to be selected for transfer into the uterus.<\/p>\n<\/div>\n\n\n\n

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      \"\"Result example 312 KB, PDF<\/i><\/span><\/a><\/div>\n\t\t\t\n\t\t\t\t\t\t\t
      \"Miscarriage in early pregnancy: diagnosis and management tactics. Clinical Recommendations\", 2016, Ministry of Health of the Russian Federation<\/a><\/div>\n\t\t\t\t\t\t\t\t\t\t
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