Down syndrome is a genetic abnormality of the fetus. During conception, the process of division and the formation of chromosomes occurs. In an ordinary person there are 46 of them, and in a patient one more - 47. Such babies after birth are called "sunny". But no matter how gentle this word sounds, Downism has its own unpleasant features: slowing down the physical and mental development... Love and attention is the main healer with an ailment.
In contact with
Signs of Down syndrome during pregnancy
This pathology does not manifest itself in any way. The mom-to-be feels just as great as during a normal pregnancy. The first weeks do not bring discomfort to the woman. The syndrome can be detected only with the help of prescribed tests and ultrasound.
Causes of possible pathologies
When the number of chromosomes changes, the correct structure of the human body is disrupted. In developing cells, a process of genetic abnormality is observed.
Causes of Down syndrome during pregnancy:
- Age barrier for women (from 35 years old);
- Heredity;
- Failure of the body when dividing chromosomes;
- Identified genetic disorders in a couple;
- Not healthy image life;
- Incompatibility of two people;
- Eating genetically modified foods;
- Ecology. Increased level of toxic elements;
- Viral and infectious diseases.
As you remember, this disease is transmitted or develops exclusively on genetic level... Medicine does not stand still, and fetal abnormalities can be determined from the 9th week of pregnancy. The main methods for detecting pathology are presented in the table.
How to identify Down syndrome during pregnancy:
- Screening test NIPT - Panorama (From week 9)
A test for Down syndrome during pregnancy is carried out on the basis of a DNA analysis of the mother's blood, taken from a vein. The result is 99% accurate and will allow you to find out any chromosomal abnormalities in the developing fetus. But this test is not suitable for multiple pregnancies.
- Ultrasound examination (13-14 weeks)
On ultrasound, Down's syndrome during pregnancy is manifested by the following signs: when a thickened collar space is detected in the area (more than 3 mm) and a change in the formation of bones in the head part, it indicates the pathology of the fetus. Also, a violation of the blood flow through the vein, an enlarged bladder, heart threshold and a strong heartbeat (from 180 beats per minute). Specialists in the field of ultrasonic scanning will easily identify any violations.
- Chorionic biopsy (10-12 weeks)
One of the unpleasant procedures. After it is carried out, the body can reject the fetus. Hardware surgery with the penetration of the device (umbrella) into the uterus, which will pinch off the fiber for analysis. After examining it, the doctor will determine the exact number of chromosomes.
- Analysis of amniotic fluid for Down syndrome during pregnancy (, 17-22 weeks)
With a special apparatus with a needle, the gynecologist pierces the abdomen, getting into the habitable environment of the embryo, and takes the amniotic fluid for analysis. After thorough laboratory tests, it provides the results. The procedure is carried out exclusively for women over 35 years old and there are prerequisites for this disease.
- Re-screening test (16-18 weeks)
It is carried out if an extra chromosome is detected, which can lead to irreversible pathology. The analysis is based solely on blood future mother.
If you find minimal flaws in the formation of the baby, do not panic, consult a doctor and follow his instructions.
What is the risk of Down syndrome?
With a healthy body, the risk of giving birth to a child with pathology is 1: 2000. For future parents over the age of 35, the figure is 1: 100, after 45 the chance of giving birth to a sick baby increases by 20%. According to fertility statistics, every 700-800 baby has Down syndrome.
The disease progresses and manifests itself in different stages of complication: mild and difficult. In a mild form, 10% of organs and body are affected, and in a severe form, up to 50%. The lower the percentage of the disease, the greater the chances of recovery.
With the help of the medical program "PRISCA", you can calculate the risk of Down syndrome and other pathologies on a computer. Data is collected:
- How many full years of the mother;
- Weight at the time of contact;
- What is the gestational age;
- The result of an ultrasound scan and examination by a gynecologist;
- The presence of chronic diseases (diabetes mellitus, HIV);
- Bad habits;
- Type of pregnancy (single or multiple).
Considering the above factors, the program will determine the risk of congenital pathology in the baby.
Undoubtedly, there is a risk of miscarriage, but not every expectant mother can intentionally kill the baby. Some women have great fear of such children and cannot firmly grasp the essence of the problem and its consequences. Only the woman decides to terminate the pregnancy, the doctor should not influence her decision in any way. The gynecologist is obliged to tell and explain: what kind of baby will be born outwardly, health problems, what difficulties in development and education are possible.
If the tests passed gave a positive result, and you are not confident in your abilities, then termination of pregnancy after the detection of Down syndrome is possible only up to 22 weeks. If the period is longer, it can lead to serious health problems.
What are the signs of a baby being born?
It will not be difficult to determine the pathology in such children. There are many signs, namely:
- Reduced skull;
- Flattened face;
- Altered ear and nose shape;
- Small parts of the face (mouth, chin);
- Shortened neck with folds;
- Small and swollen fingers (palm);
- Weak physical fitness;
- Constant opening of the mouth;
- Slight squint;
- Flat nose;
- Enlarged lips;
- Wide foot;
- Incorrect structure of the oral cavity (lack of symmetry of the teeth).
At birth with Down syndrome, all of these symptoms can be immediately observed in a child. But do not rush to a conclusion, only genetic analysis will be able to accurately tell and determine the pathology.
Sunny children have excellent abilities, they are gentle and loving. With constant physical exertion and developmental games, techniques, they will delight you with excellent results. The main thing is to love your blood, and it will thank you with positive successes.
Read more about identifying signs of Down syndrome during pregnancy in the video:
In contact with
Down syndrome is a genetic pathology characterized by the presence of 47 chromosomes instead of 46. Normally, each pair of chromosomes is represented by two copies, a total of 23 pairs of chromosomes. In Down syndrome, the 21st pair of chromosomes contains 3 copies (trisomy. Down syndrome is considered a rare disease and occurs approximately 1 time in 700 births, while it occurs with the same frequency in both sexes. Modern diagnostic methods can detect Down syndrome during pregnancy. this woman may be offered to terminate the pregnancy to prevent the birth of a sick child.
Down syndrome: causes during pregnancy
The causes of Down syndrome during pregnancy lie in the occurrence of chromosome pathologies. This pathology can develop even in absolutely healthy parents. The cause of Down syndrome during pregnancy is the formation of an additional copy of the genetic material of the 21st chromosome, or all chromosomes, or some parts of the chromosome. The causes of Down syndrome during pregnancy are in no way related to the environment, the lifestyle of the parents, taking medications and other negative phenomena. Down syndrome during pregnancy is the result of an accidental chromosomal abnormality that cannot be prevented or changed later. Therefore, with the development of Down syndrome during pregnancy, one should not look for the culprit or blame loved ones for the appearance of this chromosomal abnormality.
However, according to many studies, there is a number of factors that increase the risk of developing Down syndrome during pregnancy:
- the woman's age is over 35;
- the age of the man is over 42;
- closely related marriages;
- bad habits that can affect the quality of genetic material (smoking, drugs, alcohol).
Down syndrome: signs during pregnancy
Down syndrome, the signs of which during pregnancy can be detected only by the results of instrumental and laboratory studies, has characteristic features. Signs of Down syndrome during pregnancy at 12-14 weeks of gestation are impaired formation of the nasal bone or its absence, expansion of the collar space, impaired formation of the bones of the skeleton, the formation of neoplasms of the vascular plexus of the brain.
Laboratory diagnostic data can identify Down syndrome on early dates pregnancy. If the diagnosis was not carried out or it was decided to maintain the pregnancy, Down's syndrome becomes more pronounced by the end of the fifth month. The signs of Down syndrome will already be distinguishable by the characteristic appearance of the child, which can be seen on ultrasound: a flat face with slanted eyes, a large tongue, wide lips, and a large head shape. Also a sign of Down syndrome is a short neck, low-set auricles with adherent lobes. The upper and lower limbs will be shortened and the bones of the foot widened. There is a characteristic curvature and shortening of the little fingers. A common sign of Down syndrome is the presence of malformations of the internal organs of a child: heart, kidneys, liver, brain.
Blood test for Down syndrome during pregnancy
Ultrasound examination and biochemical blood test for Down syndrome during pregnancy are part of prenatal screening for the first and second trimesters. Screening is carried out for all pregnant women, regardless of health status and age. Screening can also identify other genetic diseases such as Edwards syndrome, neural tube defects, Patau syndrome, and others. Naturally, it is up to the woman to decide whether or not to screen.
The results of ultrasound and blood tests for Down syndrome during pregnancy allow expectant parents to make a timely decision about the further development of pregnancy. Having received confirmation of a study, including a blood test for Down syndrome during pregnancy, about the presence of pathology, a woman can terminate the pregnancy. Interruption with pathology in the early stages brings much less harm to the female body.
If the parents decide to keep the pregnancy with a child with Down syndrome, then prenatal screening will allow you to find out more information about the child's condition. Already during pregnancy with a child with Down syndrome, parents-to-be will be able to prepare for future difficulties, meet with specialists and receive advice on caring for a child from them, and find specialized development groups for children with disabilities.
Screenings of the first and second trimesters should be carried out at certain stages of pregnancy: from 11 to 13 weeks (inclusive) and from 16 to 18 weeks (inclusive), respectively. Screening of the first trimester includes ultrasound and blood tests:
- determination by ultrasound of the thickness of the collar space;
- the level of β-subunit of human chorionic gonadotropin (β-hCG) in maternal venous blood;
- the level of PAPP-A (plasma protein A associated with pregnancy) in blood plasma.
The research results are entered into the program to calculate MoM: the degree of deviation of the results from the mean, which takes into account the population and gestational age. The result of a blood test for Down syndrome of β-subunits of hCG will show increased values: more than 2 MoM. A blood test of the PAPP-A level will indicate the presence of pathology at values \u200b\u200bless than 0.5 MoM. The thickness of the collar space in Down syndrome exceeds 3 mm.
During the screening of the second trimester, blood is examined for Down syndrome during pregnancy according to the following indicators:
- the level of total hCG in the blood;
- the level of free β-subunit of hCG;
- inhibin A;
- free estriol (E3);
- alpha-fetoprotein (AFP).
The result of a blood test for Down syndrome during pregnancy for a hCG level exceeds 2 MoM. The result of a blood test for the level of free β-subunit of hCG exceeds 2 MoM. The level of inhibin A in Down syndrome will exceed 2 MoM. The level of free estriol is less than 0.5 MoM, ACE is less than 0.5 MoM.
Ultrasound analysis for Down syndrome during pregnancy in the second trimester will show a significantly smaller fetus, shortening or absence of the nasal bone, shortening of the humerus and femur bones, one artery in the umbilical cord, and a rapid heart rate.
Blood for Down syndrome during pregnancy during screenings should be donated on the same and next day after the ultrasound scan. Blood is taken on an empty stomach, preferably in the morning. A minimum of 8 hours should elapse between the last meal and blood draw. Before analysis, you can only drink plain clean water.
Ultrasound and a biochemical blood test for Down syndrome during pregnancy make it possible to suspect the development of pathology in 90% of cases. According to the results of the study, as well as the data from the questionnaire about the woman's anamnesis (to be filled in during the screenings), the possible risks of the development of pathology are calculated. To confirm Down syndrome during pregnancy, a woman is prescribed invasive research methods (amniocentesis, etc.).
A non-invasive method of examining fragments of fetal DNA in maternal blood allows detecting Down syndrome in early pregnancy. Down syndrome diagnostics is based on genome-wide sequencing of the child's DNA. A non-invasive study of Down syndrome in pregnancy is carried out using the latest generation sequencers with further mathematical analysis, which makes this method the most reliable - 99.9%.
Down syndrome analysis in pregnancy: amniocentesis
For a long time, only one test for Down syndrome in pregnancy was considered the only method: amniocentesis. This is an invasive procedure that involves puncture of the amniotic sac. The purpose of the puncture is to obtain amniotic fluid followed by laboratory study. The analysis for Down syndrome during pregnancy is performed using a thin needle that penetrates the pregnant woman's abdomen through a microscopic puncture.
Amniocentesis can detect Down syndrome, Edwards syndrome, cystic fibrosis, sickle cell anemia and other diseases during pregnancy with an accuracy of 99%. Usually amniocentesis is performed in the 1st and 2nd trimesters of pregnancy. The indication for this analysis for Down syndrome is the presence of risk factors for the development of pathologies: a woman's age over 35, unsatisfactory results of prenatal screening, the presence of fetal vascular cysts, etc.
This Down syndrome pregnancy test is not routinely used. Unlike ultrasound, which does not harm pregnancy, amniocentesis can cause miscarriage and infection. Therefore, amniocentesis is prescribed for suspicion of Down syndrome and other diseases to confirm or deny the diagnosis.
When prescribing this procedure, the final decision on its implementation belongs to the pregnant woman. If a pregnant woman is morally and financially not ready to raise a child with pathology, then to clarify the diagnosis, amniocentesis should be done as early as possible. If Down syndrome is confirmed, termination of pregnancy will be recommended, which is safer in the early stages. If a woman plans to keep the baby, regardless of the confirmation of the diagnosis, the test for Down syndrome during pregnancy will provide the information necessary to prepare parents for the birth of a child with a pathology.
The test for Down syndrome during pregnancy is carried out under ultrasound guidance to select a puncture site. Puncture is desirable to carry out extra-placental, in a place free from umbilical cord loops. If it is necessary to insert the needle transplacentally, the thinnest area for puncture is found in the placenta. The analysis for Down syndrome during pregnancy is carried out using needles measuring 18-22G. The procedure is usually performed using a puncture adapter, which allows you to control the trajectory of movement and immersion of the needle on the monitor screen. After making sure that the needle is in the required cavity, a syringe is attached to it and a fence is taken the required amount amniotic fluid. Then the needle is removed from the uterine cavity. The whole procedure takes about 15 minutes. During the insertion of the needle, a woman may feel a little discomfort, a feeling of pressure in the abdomen. Most often, the procedure does not cause strong pain and therefore does not require pain relief. After the procedure, the condition of the fetus is assessed by measuring the heart rate. The result of the analysis of amniotic fluid will be known in about two weeks.
After being tested for Down syndrome during pregnancy, a woman needs to spend the rest of the day alone, preferably taking a day off. In the first 2-3 days, you should not lift even minor weights and have sex. In the next 1-2 days after the procedure, a woman may feel small cramps in the abdomen, this condition is considered normal. You should immediately see a doctor if the spasms increase, there is a bloody or profuse watery discharge.
Start your journey to happiness - now!
The modern pregnancy monitoring program provides for three mandatory screening of a woman in the perinatal period. The main objective of a comprehensive examination is to control the quality of women's and children's health, as well as to identify possible congenital defects and developmental anomalies.
Genomic pathologies such as Edwards syndrome, Turner syndrome, Down syndrome on ultrasound are diagnosed with an accuracy of 91%. This allows the woman to decide whether to terminate or maintain the pregnancy. Signs of severe genetic damage to the fetus are determined at the first or second screening, when the possibility of abortion is still possible (up to 22 weeks). In the future, if a woman refuses to give birth to a known sick child, the gynecologist can only offer artificial childbirth. This procedure is unsafe, painful and can seriously injure the psyche.
Downism
Downism has no gender or ethnicity and is not treatable. In the process of growing up a child with Down syndrome, you can correct his behavior with the help of special developmental programs, but you cannot get rid of the genomic syndrome. The occurrence of Downism is due to intrauterine chromosomal failure. The complete set of chromosomes of a healthy organism is 46 pieces.
In Down syndrome, an additional copy of the twenty-first chromosome is formed, as a result of which there are 47 of them. The causes of the disease are not determined, but it has been established that they are not derived from the negative influence of environmental factors, psychosomatic health or the asocial lifestyle of the parents. The disease is called a "mistake of nature", which cannot be predicted and prevented.
Factors that determine the risk of having a baby with a mutated chromosome:
- hereditary genetic abnormalities (the disease is not inherited directly, but if the mother has genetic diseases, the chances of being born down are great);
- the age of the expectant mother. Women 35+ have a five-fold increase in risk compared to 25-year-old ladies. By the age of 45, this figure is 50;
- strong radiation exposure (the factor has not been thoroughly studied);
- unfavorable obstetric and gynecological history (numerous miscarriages and missed pregnancies).
Anomaly of the 21st chromosome is the main cause of pathology
In the case of multiple pregnancies, the disease affects both identical twins and only one if the children are fraternal. With a chromosomal mutation, the threat of spontaneous termination of pregnancy and the birth of a still child increases several times.
Ultrasound in the perinatal period
Examination of a pregnant woman by means of ultrasound is one of the mandatory moments of perinatal screening. If the process of carrying a child is unremarkable, an ultrasound scan is performed once in each trimester. In case of complicated pregnancy, the doctor prescribes additional ultrasound procedures. Ultrasound waves are safe for the baby and mother, therefore, the study has no restrictions on the frequency of sessions.
Diagnostics is carried out by the abdominal method (externally), without causing discomfort to the woman and the fetus.
Types of ultrasound
Scanning can be done in several ways:
- 2-D ultrasound - black and white image, only a medical specialist (ultrasound doctor) can decode a flat image;
- 3-D ultrasound - the data received from the sensor is processed by a computer program, a three-dimensional image of the embryo is projected onto the monitor;
- 4-D-method - the screen displays the baby in a three-dimensional projection, while you can observe his movements in the womb.
In the last two options, the procedure takes a longer period of time. At the request of the parents, the doctor can print a photo of the baby. In order to prevent serious problems with the health of the mother and child, it is strictly forbidden to ignore ultrasound in the perinatal period.
First trimester diagnosis
When carried out from 10 to 14 weeks, the doctor assesses the fetometry (the total size of the child), its position in the womb and the nature of the pregnancy. To identify Downism, certain markers (normative indicators) are used, with which the real picture of the study is compared.
The main defining markers are:
- TVP (the size of the collar space in thickness). The standard indicator for the amount of fluid under the skin of the embryo in the neck area should not exceed 2.7 mm. In Down syndrome, TVP is markedly increased;
- the size of the upper jaw. On ultrasound, the shortened upper jaw of the baby is clearly visible, which is characteristic feature downism;
- anatomical structure of the outer part of the ears. Underdeveloped auricles are grounds for suspicion of a genomic abnormality;
- Heart rate (rhythm or heart rate);
- absence of the main nasal bone. Downs, as a rule, have a flattened face shape. This sign indicates the presence of pathology.
For a child in the first trimester, the following indicators are considered normal:
Tachycardia (increased heart rate) is not one of the main symptoms of the syndrome, but it can be indirect. An experienced doctor will not disregard this indicator. According to medical data, the accuracy of determining Down's syndrome at the initial examination is about 90%.
Downism symptom (no bone in the nose) in a 2-D ultrasound image
Second trimester scan
The definition of Downism in the second trimester of pregnancy is carried out according to the following indicators:
- hypoplasia (underdevelopment) of the nasal bones. The nose is not visible on the monitor screen, since its size does not exceed 2.5–3 mm;
- heart disease. Children with autosomal syndrome suffer from cardiac pathologies in more than half of the cases;
- inconsistency with the norm of the size of the femurs, ilium and humerus in length. In the image, these indicators are significantly underestimated.
In addition, the doctor may see a violation of the functionality and size of other internal organs. The genetic abnormality is characterized by changes in: cerebral structures (hypoplasia of the cerebellum, frontal lobes), bladder (increase in body size).
Can an ultrasound scan determine Down syndrome with 100% certainty? Yes, you can, but only in the third trimester, when the visual signs become absolute. The decision to terminate a pregnancy through artificial childbirth or to give birth to an unhealthy child rests with the parents. The doctor can only give advice, but not insist on any position.
Additional analyzes
To confirm or refute the alleged pathology in the first half of the term, in addition to ultrasound of the fetus, a woman takes a blood test for hormonal biochemistry and undergoes invasive testing of the state of amniotic fluid and placenta.
Blood test
Down syndrome is determined by the comparative results of the following blood parameters:
- Alphatoprotein (AFP protein). Responsible for providing the child with the necessary nutrients. Analysis for genomic syndrome shows a low level;
- Human chorionic gonadotropin (hCG), otherwise "pregnancy hormone". It manifests itself in the blood from the second trimester. With Downism, it is overestimated;
- Free estriol (EZ). Female sex hormone. Determines the state and development of the uterus and uteroplacental blood circulation. With chromosomal abnormalities, it is reduced.
The results of laboratory tests significantly increase the accuracy of the diagnosis.
Biological material testing
Invasive testing is more informative. If the ultrasound showed the presence of the syndrome, the following tests must be passed:
- biopsy of the outer fetal membrane (chorion). A small fragment of the temporary organ is examined at the first screening;
- placental biopsy. Evaluation of placental cells for a period of 14 to 20 weeks;
- amniocentesis. Puncture biopsy of amniotic (amniotic) fluid, performed after the 18th week of pregnancy;
- cordocentesis (puncture of the umbilical cord vessels). It is performed through the anterior abdominal wall under ultrasound control. Carrying out is possible only in the second half of the term.
Amniocentesis is a procedure for collecting amniotic fluid (picture)
The biopath is taken in a hospital setting, since the procedure is associated with a certain risk to the fetus. It is not carried out without the consent of the woman. The analysis is carried out in a genetic laboratory.
Objective results
The diagnosis carried out according to all the rules reliably establishes the presence of a chromosomal mutation in a child. The survey results are assessed only in combination. A positive value in relation to genetic pathology should have: direct and indirect signs of an ultrasound examination, tests for hormones, biopsy results. According to statistics, there is only one baby with Down's chromosomal anomaly for every 700-800 newborns. In 85% of cases, parents decide to have an abortion or abandon a child in a maternity hospital.
Down syndrome was first described by the renowned British physician John Langdon Down, who began his research work in 1882 and published the results publicly in 1886.
This is one of those pathologies that every person has an idea of. This disease is of particular concern to expectant mothers who are anxiously awaiting the first screening. According to recent decades, this pathology occurs in every 700 born baby.
Multiple statistics recent years shows a different figure - 1 born child with pathology per 1100 newborns, which became possible due to high-precision prenatal diagnosis and early termination of such a pregnancy.
About 80% of children with this pathology are born to women younger than 35 years old - despite the relatively low risk of developing this chromosomal pathology in the fetus, in this age group there is a peak in fertility. About 5,000 newborn babies with Down syndrome are added every year around the world.
Down syndrome affects both girls and boys equally, the disease has no ethnic spread and is found everywhere.
In 2006, March 21 was the International Day of People with Down Syndrome. This day is held in order to raise public awareness of this common pathology and improve the quality of life of sick people. The number 21 was chosen due to the cause of the disease - trisomy on 21 chromosomes, and the month of March personifies trisomy, since it is the third month of the year.
The reasons for the development of Down syndrome
The causes of Down syndrome lie in the intrauterine formation of the chromosomal pathology of the fetus, characterized by the formation of additional copies of the genetically embedded material of the 21st chromosome, or the entire chromosome (trisomy), or parts of the chromosome (for example, due to translocation). The normal karyotype of a healthy person consists of 46 chromosomes, and in Down syndrome, the karyotype is formed by 47 chromosomes.
The causes of Down syndrome are in some way not related to environmental conditions, parental behavior, taking any medications, and other negative phenomena. These are random chromosomal events that, unfortunately, cannot be prevented or changed in the future.
Down syndrome risk factors
The age of the expectant mother affects the risk of developing Down syndrome in a child:
- in the age range from 20 to 24 years, the probability of the formation of this pathology is 1 in 1562;
- at the age of 25-35 years, this risk is already 1 in 1000;
- at the age of 35-39 years, the risk increases to 1 in 214;
- over the age of 45, the risk increases to 1 in 19.
As for the age of the future dad, the risk of having children with this syndrome in men over 42 has been scientifically proven.
There is a computer program "PRISCA", which takes into account the data of ultrasound, physical gynecological examinations and other factors and calculates the risk of congenital fetal pathology. To calculate the risk of Down syndrome, the risk of developing malformations of the central nervous system (neural tube defect), the following are taken into account:
- Mother's age
- Smoking
- Gestational age
- Ethnicity
- Body weight
- Number of fruits
- Diabetes mellitus
- IVF availability
Is Down syndrome inherited?
Trisomy on chromosome 21 (which is about 90% of cases of the disease) is not inherited and is not inherited; the same applies to the mosaic form of pathology. The translocation form of the disease can be hereditary if one of the parents had a balanced chromosomal rearrangement (this means that part of the chromosome changes places with part of some other chromosome, without leading to pathological processes). When such a chromosome is transferred to the next generation, an excess of genes from chromosome 21 occurs, leading to a disease.
It should be noted that children born to mothers with Down's syndrome are born with the same syndrome in 30-50% of cases.
How do you know about Down syndrome during pregnancy?
Since the causes of Down syndrome in the fetus are genetically determined, this pathology of the child can be recognized even in the womb. If Down's syndrome is suspected, signs during pregnancy are determined already in the first trimester.
Diagnosis of Down's syndrome determines the risk of developing this pathology in the fetus. The study is carried out strictly during the period from 11 to 13 weeks and 6 days of pregnancy.
- Determination of the β-subunit of chorionic gonadotropin (hCG pregnancy hormone) in the venous blood of the mother. With this chromosomal pathology of the fetus, an increased level of the β-subunit of CG more than 2 MoM will be determined;
- Determination of the level of PAPP-A - a protein-A of the blood plasma of a pregnant woman, associated with pregnancy. A high risk of the syndrome is associated with a PAPP-A index of less than 0.5 MoM;
- Determination of the thickness of the collar space using ultrasound of the fetus. With Down's syndrome, this figure exceeds 3 mm.
With a combination of the three parameters described, the likelihood of Dyne syndrome in the fetus is 86%, i.e. the diagnosis is quite accurate and indicative. To make a decision about maintaining the pregnancy or terminating it, a woman who has signs of Down's syndrome in the fetus is offered to undergo transcervical amnioscopy.
In this study, chorionic villi are taken through the cervix, which are sent for genetic research, according to the results of which this diagnosis can be confirmed or refuted with 100% reliability. The study does not belong to the group of obligatory ones; the decision on its conduct is made by the parents. Since it is associated with a certain risk for the further course of pregnancy, many refuse such a diagnosis.
The diagnosis of Down syndrome in the second trimester is also a combination screening that is done between 16 and 18 weeks.
- Determination of the level of hCG in the blood of a pregnant woman - with Down syndrome, the indicator is higher than 2 MoM;
- Determination of the level of a-fetoprotein in the blood of a pregnant woman (AFP) - with Down syndrome, the indicator is less than 0.5 MoM;
- Determination of free estriol in the blood - an indicator of less than 0.5 MoM is characteristic of Down's syndrome;
- Determination of inhibin A in a woman's blood - an indicator of more than 2 MoM is characteristic of Down's syndrome;
- Ultrasound of the fetus. If there is Down syndrome, the ultrasound signs will be as follows:
- smaller size of the fetus relative to the norm for a period of 16-18 weeks;
- shortening or absence of the nasal bone in the fetus;
- reduction in the size of the upper jaw;
- shortening of the humerus and femur bones in the fetus;
- an increase in the size of the bladder;
- one artery in the umbilical cord instead of two;
- lack of water or lack of amniotic fluid;
- rapid heartbeat in the fetus.
With a combination of all signs, the woman is offered invasive diagnostics for genetic research:
- transabdominal aspiration of placental villi;
- transabdominal cordocentesis with puncture of the vessels of the umbilical cord.
The selected material is examined in a genetic laboratory and allows you to accurately determine the presence or absence of this pathology in the fetus.
In 2012, British scientists developed a new high-precision test for the presence of Down syndrome in the fetus, the result of which is estimated at 99%. It consists in examining the blood of pregnant women and is suitable for absolutely all women. However, it has not yet been introduced into world practice.
How is the issue of termination of pregnancy resolved when determining the high risk of Down syndrome in the fetus?
When babies with Down syndrome are born, the underlying cause of the genetic malfunction is truly impossible to establish. Many parents perceive this as a test and consider themselves endowed with a special function of raising and developing such a child. But before every pregnant woman with a high risk of this pathology, the question arises of deciding the fate of her pregnancy. The doctor does not have the right to insist on interruption, but he is obliged to clarify this issue and warn about all the possible consequences. Even if pathologies incompatible with life are discovered, no one has the right to persuade a woman to decide to do it), and even more so to force it to do it.
Thus, the fate of pregnancy with fetal pathology is decided only by the parents. Parents have the right to repeat the diagnosis in another laboratory and clinic, to consult with several geneticists and other specialists.
Signs of Down syndrome in a newborn
Signs of Down syndrome in newborns are determined immediately after birth:
When children with Down syndrome are born, the outward signs listed above will be determined almost everything. The diagnosis is confirmed after passing the genetic analysis for the karyotype.
Can a child with Down syndrome grow up mentally and physically fit?
This question necessarily arises both for those parents who are still deciding whether to terminate or maintain a pregnancy, and for those who are already carrying a precious little bag with a newborn baby.
The consequences of the formation of an additional copy of a chromosome are very different and depend on the amount of excess genetic material, on the genetic environment, and sometimes on pure chance. The individual development program of such a child and, of course, the accompanying pathologies, which are observed in such children, are of great importance.
Of course, these are not deeply disabled people, but children who are able to learn, develop and become adapted individuals in the modern social environment. At the same time, it is important to understand that every child with Down syndrome will have a lag in mental, speech, physical development... It is incorrect to put them on the same line with healthy children, and it is not necessary, but it is also impossible to consider them “abnormal people”.
A special phenotype makes this pathology recognizable. Indeed, it will not work to hide such a feature of your child from prying eyes. But it is better to accept your baby from the first breath as he is, be proud of him and not hide from people. Yes, these children are special, but far from hopeless. Mothers of children suffering from much more serious pathologies would give everything for the opportunity to swap places with mothers down, if only the child could live and smile.
Did the pregnancy test show two stripes? Congratulations, very soon you will be able to fully experience all the delights of motherhood. However, do not forget that with the onset of pregnancy, a woman bears a great responsibility for the health of her unborn child. That is why, in addition to healthy nutrition, emotional calmness and good rest, during the development of pregnancy for weeks, the expectant mother visits many doctors, is registered with antenatal clinic, undergoes a large number of examinations, one of which is the analysis for down during pregnancy. Why do doctors strongly recommend this examination? In what cases does the likelihood of this pathology increase? What is the threat of refusal to undergo a down test during pregnancy? We will try to answer these and other questions of concern to many mothers.
Down syndrome. What is it?
Down's syndrome (trisomy 21 chromosomes) is a genetically determined pathology, the cause of which is the presence of an additional 47th chromosome in each cell of the body, instead of the required 46, because normally the child receives 23 chromosomes from each of the parents. This happens when the baby gets an extra 21st chromosome from the mother or father. According to statistics, for 700 healthy children there is one newborn with Down syndrome, which can be detected by analysis for down during pregnancy.
The prevalence of this chromosomal pathology does not depend on geographic location, race, gender, or other reasons. To date, some factors have been established, the presence of which increases the risk of pathology:
- Mother's age. The probability of having a child with Down syndrome in a mother under the age of 25 is 1 case in 1400 births, at 35 years old - 1 in 350 births, at 40 years old the probability increases to 1 in 60 births, and after 50 - to 1 in 12 births ... Therefore, all women over 35 years of age are shown a nadown analysis during pregnancy.
- Father's age. It has been established that the older the future father is, the higher the likelihood of a baby with Down syndrome being born.
- Closely related marriages.
- The age of the grandmother at the time of her pregnancy. The later the grandmother gave birth to her daughter, the higher the likelihood of developing Down syndrome in grandchildren. Eggs are laid even in utero, so they can be influenced by various factors. Probably, while still in the womb, some of the woman's oocytes are damaged and acquire an additional 21st chromosome. The older the grandmother, the higher the risk of giving birth to sick children for her daughter, and it increases every year, regardless of what the results of the down test were during pregnancy.
Children with Down syndrome, to one degree or another, lag behind in mental and physical development. Pathology is very often accompanied by various developmental defects that significantly reduce the average life expectancy. In addition, these children have weakened immunity, as a result of which they very often get colds, up to the development of pneumonia.
A positive test result for down during pregnancy is not a sentence. With timely assistance and proper care, a person with Down syndrome will be able to lead a full life, go to school and work, and start a family of their own. In this case, everything depends on the willingness of the parents to devote all their free time to such an unusual, but still dear baby.
Types of tests for down during pregnancy.
At this stage in the development of medicine, there are several types of examinations that allow you to calculate the likelihood of developing Down syndrome in an unborn child. The choice of method mainly depends on the gestational age. The result of the analysis for down during pregnancy is determined by a special program, taking into account the gestational age and the woman's age.
During gestation, all women who want to determine the degree of risk of developing genetic diseases in the fetus undergo non-invasive prenatal screening twice. This examination does not give a complete guarantee of the presence or absence of this or that chromosomal pathology, but only determines the likelihood of its occurrence. It is possible to accurately diagnose Down syndrome only after the birth of a child, based on external signs.
So, screening is carried out in the I and II trimester.
For the early diagnosis of Down syndrome, with a gestational age of 11-13 weeks, the following diagnostic methods are used:
- ultrasound examination of the uterus;
- biochemical blood test.
When conducting ultrasound, special attention is paid to the size of the collar zone, since in a fetus with Down's syndrome, in the back of the neck, fluid accumulates subcutaneously. In addition, the pathology is characterized by underdevelopment, or complete absence of the nasal bone in the embryo. According to statistics, in almost 70% of cases of detection of the disease, nasal bone during the ultrasound, due attention was not paid.
The biochemical analysis for down during pregnancy determines the level of β-hCG (human chorionic gonadotropin) and PAPP-A (pregnancy-associated plasma protein A). Such a study allows you to determine the pathology in 80% of the affected embryos.
In the second trimester, at about 16-18 weeks, a triple test is performed - an analysis for down during pregnancy, which determines the level of AFP (alpha-fetoprotein), free estriol and β-hCG.
Alpha-fetoprotein is a special protein produced by the liver of the fetus. After entering the amniotic fluid, AFP enters the woman's venous bed. With the course of pregnancy, its amount constantly increases, reaching a maximum value by 30 weeks of gestation. A low level of AFP, in accordance with the gestational age, may indicate the presence of Down syndrome, and its increased amount - about the pathology of the neural tube.
All studies can show both a false negative and a false positive result. The accuracy of the methods ranges from 70-90%.
Amniocentesis is an invasive down analysis during pregnancy.
If, as a result of the tests for down during pregnancy, a high risk of this pathology in the fetus was established, the woman is offered to undergo an invasive diagnostic method - amniocentesis.
Amniocentesis is a procedure for taking amniotic fluid for a more thorough examination. Such an analysis for down during pregnancy is carried out not earlier than the 18th week of the development of pregnancy and in the presence of amniotic fluid in sufficient quantities. After confirming the diagnosis with the help of amniocentesis, the woman must independently decide whether to give birth to her sick child or terminate the pregnancy.
