Determination of Down syndrome by ultrasound. Down syndrome

14.08.202127.05.2017

Today, doctors strongly recommend that absolutely every expectant mother undergo a genetic risk test. The mandatory list of examinations for genetic pathologies includes a Down test during pregnancy. Some immediately and unconditionally agree to undergo such a diagnosis, while others believe that it is better not to know anything at all for the time being.

This approach can have serious consequences in the future. After all, it is very important to understand that a child born with Down syndrome is mentally and physical development, from the moment of birth, he is diagnosed with serious diseases, often incompatible with life. In society, such a child, with rare exceptions, is considered a black sheep.

If quite recently a test for Down syndrome was prescribed for a woman over 35 years of age, or for parents over the age of 45, now this examination is mandatory for everyone. Down syndrome is getting younger, and there is no guarantee that healthy, prosperous and young parents will not have a baby with one extra chromosome. Unfortunately, such a diagnosis often leads to termination of pregnancy according to indications.

What is Down syndrome

Nature very wisely works on each new person. When laying out the genetic scheme, it is assumed that the future baby will have 46 chromosomes - 23 of them were inherited from the mother and the same number from the father. Often there is a duplication of one chromosome out of 21 pairs. And then instead of the required 46 chromosomes there become 47. This is evidence of the alleged Down syndrome.

The pathology being studied does not have continental or racial advantages. Absolutely everyone can be at risk. However, doctors have identified a number of factors that provoke the birth of children with Down syndrome:

age of the future mother and father 35+;
the baby’s parents are blood relatives;
Doctors often list the grandmother’s age as a risk factor. The later the grandmother gave birth to the mother, the higher the risk of having a grandson with a pathology in the chromosome set.
parents are owners of a hidden mutation of chromosome 21. One of its sections adheres to chromosome 14 and coexists with it. Outwardly there are no signs of this. Scientists call this phenomenon “familial Down syndrome.”

Scientists have proven that neither the environment, nor nutrition, nor the lifestyle of future parents can reduce or increase the risk of having a sick child. This is an abnormality that occurs at the chromosomal level. It cannot be prevented or prevented in any way.

Children born with Down syndrome are very weak. There are often cases when such a baby does not live to see a year. Numerous malformations of all organs, weak immunity, special functioning nervous system, foci of brain damage - all these are consequences of the appearance of one extra chromosome.

It is important for a woman who has been given this terrible diagnosis to know that with proper care and boundless love, “sunny” children can live a wonderful life, go to school, and play sports. This requires great moral and physical strength from the parents.

Methods for diagnosing Down syndrome in pregnant women

Today, the most informative way to examine pregnant women for chromosome pathology is screening. This is a set of studies that can identify genetic and chromosomal abnormalities. In addition to Down syndrome, such a diagnosis can promptly detect Edwards syndrome, Patau syndrome, and congenital neural tube defects.

In the first and second half of pregnancy, diagnostics is required, consisting of a biochemical blood test and ultrasound.

Ultrasound examination

In the first trimester, weeks 11 to 13 are prescribed.

When making a diagnosis, the ultrasound specialist pays attention to the following points:

Indicators	Deviations from the norm
Nose bones	Shorter than normal developing fetus, or absent altogether.
Collar width	More than 3 mm. The norm is 2 mm. The space between the neck bone and the skin has increased. Liquid collects in it.
Shoulder and femur bones	Shorter than they should be according to the norm
Brain condition	Presence of cysts, disruption of venous blood flow
Iliac pelvic bones	Short, obvious increase in angle
The size of the fetus from the crown to the tailbone	Less than 45, 85 mm.
Heart condition	Pathology of cardiac muscle development

Even if an ultrasound examination yielded a preliminary disappointing diagnosis, there is no need to panic. It can be considered accurate only if several signs are combined at once.

Biochemical blood test

A blood test taken from the expectant mother for Down syndrome, combined with ultrasound results, can significantly clarify the picture and help identify genetic abnormalities.

In the 1st trimester, up to and including the 13th week, a “double test” is taken, that is, the risk of an extra chromosome is diagnosed using two markers:

Human chorionic gonadotropin (hCG) is a protein hormone produced by the membrane of the embryo.
Specific blood plasma protein PAPP-A

The reliability of such research is 85%.

Blood is donated on the same day as the ultrasound examination, on an empty stomach. If the mother is not feeling well, she is allowed to drink some plain water before the examination.

In the second trimester, from weeks 15 to 18, screening is repeated. In this case, the test is called a “triple test”. The level of three proteins and hormones is determined at once:

alpha-fetoprotein is a protein produced by the fetus and enters the mother’s blood;
free estriol.

Deciphering the results of a blood test for Down syndrome should be carried out as carefully as possible during pregnancy. Incorrect interpretation leads to a false diagnosis, which can lead to irreparable consequences.

Medical error is not uncommon in modern reality. The gynecologist is obliged to study the results of both screenings and only then add the woman to the risk group.

All these research methods do not detect a specific pathology, but reveal the degree of risk of its occurrence. The risk can be low with a result of 0.1-1% and high with a result of 1% or more. All these are averages.

At medium and high levels of risk, a control expert ultrasound is prescribed, where an experienced doctor will thoroughly assess the condition of the fetus.

Amniocentesis

When standard diagnostics do not provide a clear picture of the course of pregnancy, the expectant mother may be prescribed tests related to the collection of amniotic fluid. This test is called amniocentesis.

Amniotic fluid is taken under ultrasound control with a special needle through the abdomen or vaginal opening.

It is advisable to carry out such diagnostics after the 18th week of pregnancy, since it is at this period that the required amount of amniotic fluid becomes available.

Amniocentesis is carried out strictly according to indications, since it is not entirely in a safe way detection of chromosomal pathologies.

This examination technique is not suitable for a certain category of women:

there is a threat of spontaneous abortion;
placenta along the anterior wall;
disturbances in the development of the uterus;
chronic diseases of the mother.

Non-invasive prenatal diagnosis of aneuploidy using maternal blood

Today, the safest and most informative way to diagnose and identify chromosomal pathologies of the fetus without interfering with the fragile bond between mother and unborn baby.

Fetal DNA is isolated from the mother's blood and examined for pathological abnormalities in the chromosome set.

Efficiency reaches 97%. In this case, Patau syndrome is detected on the 13th pair of chromosomes, Edwards syndrome on the 18th, and Down syndrome on the 21st.

Detection of Down syndrome in a newborn

Children born with chromosomal Down pathology have a number of specific external signs:

The special appearance of such children is due to a chromosomal abnormality, so Down’s babies do not resemble any of their parents.

The decision to undergo or not to undergo screening for Down syndrome during pregnancy rests solely with the woman. Doctors can only advise and recommend. So, if at the first screening a preliminary diagnosis is revealed, and the woman remains firm in her intention to give birth to such a baby, then it is not worth taking the risk and undergoing more serious research.

It is a completely different matter when the expectant mother is not ready to raise a child with Down syndrome. Then the need for unsafe tests to detect pathology is obvious.

It is important to remember that even in the most dire cases there is a way out. There is always a chance to give birth to a healthy and strong baby. But if, nevertheless, a “sunny” child has been sent to you, you need to endlessly love and care for him.

It is impossible to diagnose whether a child has a pathology with 100% certainty. However, Down syndrome does have symptoms during pregnancy.

Several tests, when combined with each other and risk factors such as age and family history, can give an estimate of the likelihood that a child carries the trisomy 21 gene. Ultrasounds of fetuses with Down syndrome are performed, and diagnostic tests are offered that determine whether the child carries gene, but they have a risk of miscarriage.

Under normal circumstances, a human cell contains 23 pairs of chromosomes, with each pair consisting of one chromosome from each parent. Down syndrome, also known as , occurs when a baby has an extra copy of chromosome 21 in some or all of its cells

Why it appears, the causes of Down syndrome (an additional complete or partial chromosome) in the fetus are still unknown. Age-related risk of trisomy 21 is the only proven factor. 80% of children with Down syndrome are born to women after 30 years of age.

Anyone can have a baby with a chromosomal abnormality

Contrary to popular belief, the child does not inherit Down syndrome.
The only type that can be passed from parent to child is the VNI translocation. However, this is a rare form, diagnosed on early stages pregnancy.

Inheriting a translocation means that the father or mother has rearranged genetic material. This means that the person is a balanced carrier, one who has no signs or symptoms but can easily pass it on to a child.

Risks of trisomy

Talk to your doctor to find out if you are at risk for Down syndrome during pregnancy.
The expected risk of trisomy 21 is the underlying cause of Down syndrome in almost 95% of cases. In this case, the child receives three copies of chromosome 21 in all cells instead of two, one from each parent.

It occurs as a result of abnormal cell division while sperm or eggs are developing. People with this type have (47 instead of 46) in each cell.
Risk factors may vary depending on the type of abnormality.

Trisomy 21 basic risk:

The risk of having a child with a genetic problem increases as a woman gets older.
There is a previous pregnancy in which the fetus had Down syndrome. Women who have had a pregnancy with trisomy 21 have a 1-in-100 chance of having another similar child.

Mosaicism. This type is caused only by certain cells producing 47 chromosomes. Mosaicism occurs in 3 out of 100 people with Down syndrome. Risk factors for mosaicism are similar to those for trisomy 21.

Trisomy 21 individual risk arises from translocation - the only one that can be transmitted through families. A person with this type has 46 chromosomes, but part of one chromosome breaks and then attaches to another chromosome.

You may be a carrier of a translocation chromosome if you have:

Family history of Down syndrome.
Have had other children with this pathology.

Is it possible to detect Down syndrome using an ultrasound?

There is a small chance that a specialist will detect Down syndrome on an ultrasound. These include an increase in skin volume in the back of the head, a decrease in the size of the hip, or cysts in the brain. According to doctors, Down syndrome cannot be diagnosed by ultrasound. This test will not detect the expected risk of trisomy 21.

Ultrasound imaging at 20 weeks can be used to screen for Down syndrome in the fetus.

1 Ultrasound of a fetus with a large bladder 2 Enlarged NT and missing nasal bone in an 11-week fetus with Down syndrome

Echo signs of Down syndrome on ultrasound, which indicate an increased risk when observed in the second trimester of pregnancy.

A fetus with Down syndrome may have a small or absent nasal bone, large cerebral ventricles, a thick nuchal fold, and an abnormal right subclavian artery.
The presence or absence of many signs is more accurate.

Down syndrome occurs as a result of a gene mutation when an extra forty-seventh chromosome is formed in the embryo's body. It is impossible to notice obvious signs during pregnancy with such a child - they simply do not exist.

Chromosomal disruption occurs at the stage of fusion of the egg and sperm, so it is no longer possible to influence it during pregnancy. There are no methods for treating it, so it is very important to make an accurate diagnosis as early as possible so that parents can decide the future fate of the fetus.

Causes

Down syndrome is a chromosomal abnormality, not a disease. Therefore unfavorable external factors, reception medicines, alcohol, nicotine, as well as the lifestyle of both parents do not have any influence on its occurrence.

Pathology does not depend on gender, race and class. The risk of the syndrome is influenced only by the age of the parents.

According to statistics, women aged:

from 18 to 25 years old the probability is 1:1562;
from 25 to 35 years it increases to 1:1000;
from 35 to 40 years old it makes a sharp jump of 1:214;
after 40 years it is equal to 1:19.

The age of the father also affects the occurrence of the described chromosomal mutation. After 42 years of age, men have an increased risk of their children developing Down syndrome. The birth of a girl after 35 years of age increases the likelihood of this pathology appearing in her descendants.

Men born with this mutation are infertile in most cases, but 50% of women are capable of childbearing. But at the same time, half of them have children with signs of Down syndrome or other congenital abnormalities.

Diagnostic methods

To identify signs of Down syndrome in the first and second trimester of pregnancy, the following diagnostic methods are used:

biochemical screening;
invasive techniques.

Ultrasound

The first signs of pathology during ultrasound can be detected at 14 weeks.

The measurements taken during this process are called ultrasonic markers. These include:

thickness of the collar space, observed in 75% of cases;
heart defects;
atresia (closing of the lumen) of the duodenum;
shortened nasal bone or its complete absence;
heart rate exceeding 170 beats per minute;
the presence of only one artery in the umbilical cord, while other embryos should have two;
shortened humerus and femurs;
enlargement of the renal pelvis;
choroid plexus cysts located in the brain.

If several of these signs are detected, the doctor can make a preliminary diagnosis and prescribe a biochemical blood test.

The percentage of probability of detecting the described pathology based on the results of all the listed tests in the first trimester of pregnancy is about 91%. The final diagnosis is carried out at 20 weeks of pregnancy.

At this time, the following signs become noticeable during an ultrasound:

round head shape with sloping forehead and flat face;
deformation of the chest, in which it takes on a keeled or funnel-shaped shape;
small upper jaw;
delayed growth of limbs;
curved shortened little fingers.

The most complete picture can be seen using the 3D ultrasound method, in which a three-dimensional image of the fetus is displayed on the screen.

This method significantly increases the percentage of detection of signs of Down syndrome, starting from 14 weeks of pregnancy. But, unfortunately, it has not yet become widespread due to the high cost of the equipment, which not every clinic can afford.

Biochemical screening

Since an accurate diagnosis cannot be made only based on ultrasound results, additional blood tests are prescribed.

They include:

determination of hCG indicators;
detection of free estriol;
a test for alpha-fetoprotein, an increased concentration of which is one of the symptoms of Down syndrome;
determination of plasma protein A.

These methods involve taking blood from a woman’s vein during pregnancy and do not pose a risk to the life of the unborn child. However, like ultrasound examinations, they do not provide a 100% guarantee of the presence of pathology. Therefore, invasive methods are used to definitively confirm the diagnosis.

Invasive techniques

Such studies involve taking blood or skin from the fetus for genetic testing. They carry a certain risk for the health of the fetus, so not all women decide to undergo them.

The following invasive procedures are distinguished:

A combination of ultrasound methods, invasive and non-invasive studies, as well as the study of the anamnestic data of the parents (age, the presence of a predisposition to genetic abnormalities in the family) makes it possible to make an accurate diagnosis of the presence or absence of Down syndrome in the fetus.

Children with the described pathology at birth have the following signs:

flattened shape of the face and back of the head;
open small mouth;
large tongue;
saddle nose shape;
there is a thickened skin fold on the neck;
strabismus;
underdevelopment of the middle phalanges of the fingers;
wide palms with a single transverse fold.

Anomalies such as anal fusion, duodenal stenosis, and heart defects are also possible. There is a high risk of developing leukemia.

Possible actions after diagnosis

The law allows termination of pregnancy due to the detection of signs of Down syndrome in the fetus. This manipulation can be carried out up to 22 weeks without threatening the life of the mother. However, not all parents decide to take such a step. This may be due to religious or moral principles, hope for possible error doctors when making a diagnosis, acceptance of the child as he is given by nature, and other factors.

Any choice is worthy of respect, and the decision to have an abortion should not be viewed as a manifestation of selfishness or cowardice. After all, caring for a Solar child requires enormous moral, physical and material costs. In addition, a society that, on the one hand, condemns abortion and demands its ban, on the other hand, is not able to adequately perceive and support special people.

A positive factor is that doctors have developed physiotherapeutic techniques that allow a child with this pathology to develop all the skills that a person needs to care for himself independently. Subsequently, such a child will be able to get an education and even master a profession.

Down syndrome is a common genetic abnormality. Statistics show that out of 700 newborns, 1 is born with a similar pathology. This does not depend on race, climate zone, skin color or nationality.

During pregnancy diagnostics Additional chromosome
Planning inside planned
camera photography

Children with Down syndrome are born with the same frequency; during pregnancy, a woman may not be aware of the pathology, but it is possible to determine this anomaly.

The word "syndrome" implies the presence of a certain sign or characteristic feature. He was named after the doctor who described this anomaly, John Langdon Down. The syndrome arose as a result of an anomaly, a disruption in the process of cell division. This syndrome occurs when the body has an extra chromosome. This chromosome can affect the body and general development baby.

Nature dictates that a person has 46 chromosomes in each cell; they have an equal proportion of genetic information from their parents. A person who is born with this syndrome has an extra chromosome, and its occurrence is still a mystery.

These children have delayed development, physical and mental. This pathology can also be accompanied by a number of other diseases. It is more difficult for them to adapt to our world; it is more difficult for children to study alongside their peers. But, nevertheless, there are cases when a person lives a relatively full life, goes to school, plays sports.

Experts know how to use tests to recognize that a child will be born with Down syndrome even during a woman’s pregnancy. The test is done for many reasons. More than 90% of women terminate their pregnancy after receiving the diagnosis. More than 92% of couples abandon their child at birth. More than 30% of cases end in miscarriage.

To reassure yourself, it’s enough to get tested regularly

Only a small percentage of children with this diagnosis can fully live in harmony and understanding with loved ones. Many people with the syndrome live to be 60 years of age or more. Life expectancy is affected by a disease - heart disease.

Main signs of anomaly

Now it is possible to determine pathology in the early stages. When performing an ultrasound, which is scheduled to be performed from the 14th week of pregnancy, a specialist may detect a violation in the formation of the baby’s structure:

by expansion of the collar zone, which exceeds the norm by more than 5 mm;
echogenicity (too bright image on the ultrasound machine monitor) of the intestines;
the presence of heart disease.

Also, signs by which Down syndrome can be identified during pregnancy may be dilation of the renal pelvis, the formation of a choroid plexus cyst in the brain. The specialist will immediately note that the fetus is missing a nasal bone and has neck folds. They mean that subcutaneous fluid accumulates there. This is all characteristic features pathology.

Sometimes you can see wide lips, a flat tongue that will have a longitudinal groove. The head shape will be round and have a slightly sloping forehead. The neck of such a child is short, and the earlobes grow to the head. Thanks to ultrasound during pregnancy, it is not difficult to identify Down syndrome.

Final diagnosis can only be made after the 5th month of pregnancy. The syndrome is easily recognizable and has its own differences in appearance. On an ultrasound scan, the child will have slanted eyes and a flat face. The woman also undergoes certain tests that can also determine pathology. They are taken from 11 to 13 weeks of pregnancy.

Risk of developing pathology

The syndrome is not a disease, it is a pathology that cannot be prevented or cured. The child has an additional chromosome on chromosome 21, as previously described, for a total of 47.

Extra chromosome

In women over 36 years of age, the likelihood of an anomaly increases (1 in 30). Therefore, it is so important to take blood tests on time and undergo routine examinations during pregnancy - this will help to identify Down syndrome in a timely manner and help make a decision in a timely manner.

The main risk factors are:

the age of the mother, but this is a non-critical factor, such children are often born to young women, the age of the father does not particularly affect the syndrome - this is due to the fact that the man’s cells are renewed every 72 days;
female eggs, starting from the moment of birth, absorb all toxins, harmful chemicals, unhealthy lifestyle - alcohol, cigarettes, all this negatively affects future pregnancy;
if a family has a “special” child, there is a small percentage that the second child will have the same anomaly;
The risk of developing Down Syndrome also increases if the spouses are consanguineous;
exposure to radiation, heavy metals;
it is believed that if a grandmother gave birth to her daughter over 37 years of age, there is a possibility that her grandchildren will have such a pathology.

Causes of pathology formation

As such, there are no exact reasons for the development of such a syndrome. A child with such a deviation can be born to a completely healthy, young couple. But, nevertheless, the main criteria are identified when a woman during pregnancy can be diagnosed with fetal pathology with Down syndrome:

woman's age under 18 and over 35 years;
formation of an additional chromosome;
heredity;
maternal health;
marriages between relatives.

There are three types of syndrome:

standard trisomy is a complete tripling of chromosome 21, this type of pathology is the most common, it can be found in more than 92% of cases;
chromosome translocation - this type of anomaly can be inherited from parents, it can be found no more often than in 5% of cases;
mosaic form - occurs in only 2%, with this type of pathology the tripled chromosome is located in individual cells of the body, sick people have the usual appearance And intellectual development, but they are more likely to have a child with Down syndrome.

It is still impossible to determine the exact reasons why pathology develops during pregnancy. But, nevertheless, anomalies are happening more and more often. It has also been noted that in more developed cities there are slightly fewer cases of births of “sunny” children. Perhaps factors such as the environment, level of income or nutrition are important here.

Planning for Healthy Children

In order to give birth to healthy children, parents need to take care in advance.

It is necessary to undergo consultation with genetic specialists.
Perform perinatal (prenatal) diagnostics. It includes ultrasound, determination of the level of alpha-fetoprotein in the blood serum of a pregnant woman, amniocentesis, chorionic villus biopsy, cordocentesis ().

Full diagnostics

Who is mainly at risk and who needs genetic counseling:

families whose pedigree has a predisposition to hereditary diseases;
women who have experienced several spontaneous miscarriages, during the next pregnancy it is necessary to undergo examinations to identify the risk of developing Down syndrome in the fetus;
who had cases of stillbirth;
if the future parents have recently been exposed to radiation, close contact with chemicals, or work in hazardous work;
those who took drugs with a teratogenic effect (causes mutations in genes);
those who lead an unhealthy lifestyle;
men over 45 years old.

After consultation with genetic specialists, it is necessary to conduct a perinatal diagnosis, the purpose of which is to determine the health of the baby in the womb.

Planning for a healthy baby

It is necessary to determine the time that has passed since the cessation of contraception. Experts believe that after a woman stops taking oral contraceptives or after removing the IUD, it is necessary to refrain from conceiving for at least 2 to 3 cycles. During this period, hormonal balance is normalized, which is affected by the use of contraceptives. The walls of the uterus and the activity of the fallopian tube are restored. In general, the body is ready for subsequent pregnancy; the risks for diagnosing a pathology, such as Down syndrome, become less.

You need to wait until after the baby is born. Doctors recommend that the period between births be at least two years. If a woman has experienced C-section, it is especially necessary to observe the time interval. You also need to take into account the gap between feeding and conception (at least 6 months must pass).

Tests to detect pathology

At the beginning of pregnancy and several months before it, doctors recommend starting to take vitamins, especially folic acid. This is necessary so that the woman’s body is prepared to bear a child. And also in order to minimize the development of pathologies.

After a woman becomes pregnant, after certain period she is undergoing a routine examination. It is also necessary to take tests to detect the formation of pathology during pregnancy.

Basic tests that can show that the fetus is developing Down syndrome:

An ultrasound is performed from 10 to 13 weeks of pregnancy - the width of the cervical translucency and the nasal bone are examined;
take a blood test for hCG (chronic gonadotropin) from 10 to 13 weeks, for AFP (Alpha Feto Protein) from 16 to 18 weeks (AFP is a substance that is synthesized by the child’s liver, transferred to the amniotic fluid and then into the mother’s blood);
tests for infectious diseases;
amniocentesis - amniotic fluid is taken from the amniotic sac (after 18 weeks).

: Borovikova Olga

gynecologist, ultrasound doctor, geneticist

Signs of Down syndrome during pregnancy can be detected at 10–14 weeks. The first test results may be false positive. Final conclusions can only be drawn after a comprehensive examination. Modern medicine focuses on diagnosing anomalies close attention. Children with chromosome disorders are special. Caring for and raising such a child requires a lot of moral strength, free time and finances from parents. Early prenatal diagnosis allows a woman, after weighing the pros and cons, to make a decision regarding pregnancy.

Down syndrome is a genetic defect characterized by a chromosome disorder. Normally there should be forty-six chromosomes. Children born with Down syndrome have one more. This affects the overall development of the baby and his health.

Special children are born often. According to statistics, a chromosomal abnormality occurs in one newborn out of 700. Children with this diagnosis are called “sunny”. They are trusting, smile all the time, and do not know how to get angry. However, due to mental and physical disabilities, it is difficult for “sunny” children to adapt to life in society. It is impossible to accurately predict how a child with a chromosomal pathology will develop. Just as it is impossible to cure a genetic defect. Difficulties also arise in determining the causes of the syndrome. However, despite all the difficulties in understanding a genetic failure, it can be determined in utero. Tests help identify chromosomal abnormalities. They allow you to recognize the signs of the syndrome in the first trimester.

Causes of Down syndrome

Genetics is an extremely complex science. Doctors cannot give an exact answer as to why certain genetic mutations occur, in particular why an extra chromosome occurs. A “sunny” baby can be born to an absolutely healthy couple. It has long been proven that the lifestyle of partners, taking medications during pregnancy, and external factors often affect the course of pregnancy and the development of the fetus. However, none of these factors is the cause of the gene failure. Of course, pregnancy needs to be planned and the first step to birth is healthy child is to reconsider your lifestyle. This reduces the risk of the fetus developing various diseases, but not genetic defects.

A chromosomal abnormality can be called a mistake of nature. But still, geneticists identify several factors that increase the risk of having a special child:

It is believed that a “sunny” child is highly likely to be born to a woman whose mother gave birth to her after thirty-seven years of age. The presence of a genetic malfunction is often associated with a lack of folic acid in the mother's body. There is indeed a relationship between low folate levels and congenital mutations. However, the effect of folic acid specifically on the chromosome set requires additional research and evidence.

Many factors that trigger the appearance of an extra chromosome remain a mystery to geneticists. The appearance of gene defects occurs at a level that medicine has not yet had time to understand.

Is it possible to prevent pathology?

Preventive measures help avoid the development of many diseases in the fetus. But, unfortunately, there is no prevention of genetic abnormalities. However, doctors give several recommendations to at least minimally reduce the risk of developing Down syndrome:

pregnancy needs to be planned;
you should not delay the birth of your child: it is advisable that the mother’s age does not exceed 35 years;
taboo on family ties between partners;
before and after conception you need to consult a geneticist;
at the planning stage, and then in the first trimester, a woman is recommended to take folic acid and multivitamins.

Once you become pregnant, you need to register with an antenatal clinic as early as possible. This is a guarantee of timely diagnostic analyzes and tests aimed at identifying signs of various pathologies of the embryo.

Screening-diagnosis of chromosomal abnormalities in the fetus

Modern medicine can diagnose Down syndrome in utero. Expectant mothers are offered to undergo screening diagnostics, which allows them to identify disorders of embryonic development and identify signs of various pathologies. Is it necessary to undergo research? What signs of Down syndrome in a fetus does a comprehensive examination reveal? Do tests and other diagnostic measures carry additional risks for pregnancy? For many women in an interesting position, it is important to find answers to these questions. In each individual case, only a doctor can give comprehensive answers.

How to determine Down syndrome during pregnancy? Previously, the birth of special children was a shocking surprise for parents. Thanks to modern medicine, it is possible to identify a genetic abnormality during the period of intrauterine development. There are several diagnostic methods to suspect a chromosomal abnormality in the fetus. Primary testing comes down to non-invasive methods. These include:

hCG analysis;
AFP analysis.

Between the tenth and thirteenth weeks of pregnancy, expectant mothers undergo a routine ultrasound. This procedure is not intended to detect Down syndrome. It allows you to determine how the fetus develops as a whole and to see deviations from the norm. However, according to the results of ultrasound, it is possible to assume a genetic chromosomal pathology in the embryo.

The accuracy of screening diagnostics largely depends on the qualifications of the specialist and the availability of modern equipment in the clinic. In combination with an ultrasound, a blood test is done for Down syndrome. The analysis can be considered informative already from the 14th week. It is used to determine biochemical markers in blood serum. For antenatal diagnosis of chromosomal abnormalities, hCG and AFP readings are important. When test results show low protein and hormone concentrations, the likelihood of a genetic disorder is high. However, it is impossible to accurately determine the presence of the syndrome in an embryo based on this sign.

Analyzes must be repeated according to schedule. If there is a high probability of a chromosomal abnormality in the fetus, the doctor will give a referral for additional diagnostic tests and tests. The expectant mother should remain calm until the diagnosis is clarified. Subsequent diagnostics often do not confirm screening.

Signs of Down syndrome according to ultrasound

Ultrasound cannot accurately determine whether a fetus has Down syndrome, but signs during pregnancy can be recognized using ultrasound. A deviation from the norm is indicated by:

increased collar space;
hypoplasia of the nasal bone;
the size of the fetus is smaller than normal;
reduced upper jaw;
shortened femurs and humeri;
enlarged bladder;
rapid heartbeat;
the presence of only one umbilical artery;
changes in blood flow;
lack of amniotic fluid or oligohydramnios.

The main marker of the syndrome on the first ultrasound is the size of the collar space. Each fetus has a small amount of fluid in the cervical area, which forms the diameter of the collar space. For transvaginal ultrasound, 2.5 mm is considered acceptable. If the procedure is performed through the abdominal wall, then a result not exceeding 3 mm can be considered normal. Elevated readings are the first sign indicating Down syndrome. Primary diagnosis is carried out when the time frame is still short, so other signs are rarely detected.

In the second trimester, ultrasound evaluates the length of the fetal nasal bones. This indicator is important for making a diagnosis. Every second child with a chromosomal abnormality has hypoplasia of the nasal bone. After 16 weeks, using ultrasound, you can already see more signs characteristic of genetic pathology, if any.

Ultrasound does not always help determine the syndrome. However, it indicates that the pregnancy is risky. The results of the ultrasound procedure determine whether additional diagnosis of Down syndrome is needed during pregnancy.

Invasive diagnostic methods

When the initial tests show a positive or questionable result, the doctor prescribes additional procedures. They help make an accurate diagnosis. Specific diagnostic methods are invasive in nature. These include:

amniocentesis;
cordocentesis;
chorionic villus test.

At the tenth to twelfth week, if indicated, a chorionic villus biopsy can be performed. This procedure involves the collection of the outer membrane of the fetus and subsequent examination of the material. The chorionic villi can be used to identify the genetic characteristics of the fetus. The collection of material involves penetration into the uterus. The analysis results will be ready in a couple of days.

Starting from the seventeenth to twenty-second week, the doctor may recommend that the expectant mother at risk undergo a procedure for collecting amniotic fluid. This method is called amniocentesis. Amniotic fluid can tell you about the baby's chromosome makeup. A special needle is used for the procedure. With its help, a hole is created in the fetal membrane. After collection, the liquid is examined in laboratory conditions. The results will be ready only in two to three weeks. Cordocentesis can be performed in parallel. This method involves studying cord blood.

Risks of additional diagnostic methods

Using invasive methods, Down syndrome is diagnosed with virtually no errors. However, the procedures are characterized not only by high accuracy, but also by the risks of pregnancy complications. Such risks include:

miscarriage (the highest incidence is observed with chorionic villus biopsy - 3%);
effusion of amniotic fluid;
embryo infection;
detachment of membranes.

Due to possible complications, invasive methods are not widely used. Tests are carried out for pregnant women for special indications. If the initial screening does not reveal factors indicating Down syndrome, then special tests are not prescribed. Expectant mother should be aware of the risks of specific prenatal tests. Parents independently decide whether to conduct an additional examination. Tests are optional.

A consultation with a highly qualified specialist will help you take a balanced approach to the issue of the need for invasive procedures aimed at identifying Down syndrome in utero.

What to do if the diagnosis is confirmed?

If a Down test during pregnancy confirms signs of a gene disorder, parents will have to make a difficult decision. The pathology cannot be cured either in utero or when the baby is born. You can't argue with genetics. Once the diagnosis is established, there are two options: have an abortion or give birth to a child with a genetic abnormality. Abortion for medical reasons can be done at any stage. If Down syndrome is detected in the fetus, the doctor does not have the right to refuse to terminate the pregnancy. But he cannot insist on this either. The doctor’s task is to correctly diagnose and warn about possible risks. Final decision always remains with the parents.

Once you learn that screening has shown signs of a chromosomal defect, it is important not to take hasty steps. You must first wait for confirmation of tests for Down syndrome, because diagnostic errors often occur during pregnancy. Screening is not able to give a 100% guarantee that a baby with a genetic abnormality is developing in the womb. It is advisable to consult with several geneticists. It is important to remember that accurate screening results can only be obtained with modern equipment. This is why you need to choose a good clinic for your first ultrasound. According to the recommendations of doctors, it is necessary to undergo specific prenatal diagnostic procedures.

If a woman decides to give birth to a child with a chromosomal abnormality, she should be prepared for the fact that it will not be easy. But proper care, stimulation of development and appropriate upbringing help turn a “sunny” child into a full-fledged member of society.

Prognosis for Down syndrome

Children with Down syndrome always experience delays in physical and mental development. However, developmental forecasts depend entirely on the parents’ willingness to care for their special child. If you invest a lot in a child with a genetic pathology, then speech and intellectual delays will not be so noticeable. “Sunny” children can be trained and adapted to society. However, everything is much harder for them than for their peers.

The primary task of parents is to develop the child’s speech and communication skills. A special baby needs medical supervision. It should be carried out throughout life, because over time, symptoms of concomitant diseases may appear. For example, in parallel with genetic pathology, heart disease and severe gastrointestinal anomalies often develop. Subject to appropriate medical and social support, doctors give the following forecasts:

The child will learn to walk and talk, although speech problems are inevitable.
A special child is able to comprehend the basics of literacy. However, it is important to consider that this is more difficult for him than for other children.
A “sunny” child can study not only in a specialized school, but also in a general education school.
People with Down syndrome can become part of society: find friends, enter into marriages, work, realize themselves in creativity.
People with this diagnosis today live on average 50 years. Although until recently the average life expectancy was significantly lower.

Having decided to continue the pregnancy, despite the diagnosis, you need to focus on positive prognoses. All over the world, people with genetic disorders live ordinary life. This is possible even in the CIS countries, where close attention has been paid to the issue of adaptation of special children to society in recent years.