Fetal pathologies: at what stage are they detected, what tests to take, who is at risk. Which birth defects are more common? Prevent the birth of a child with defects

19.04.2010 00:00:00

Like most expectant parents, you're probably worried about your baby being born healthy. Or maybe you were told during prenatal screening that your baby might be born with a birth defect.

Many parents assume that all birth defects are a serious or even fatal problem, but the fact is that many are treatable, often immediately after birth - and sometimes even before the baby is born.

It is especially important to know the risk factors and ways to prevent birth defects. It is also important to understand that most children are born with birth defects, even when both parents are completely healthy.

About birth defects

Congenital defect is a disorder in the structure and functions of the body or in metabolism that arose even before the birth of the child. These disorders lead to mental or physical disability, or death.

There are more than 4,000 different known birth defects, minor and major. Many of them are treatable, but birth defects are the leading cause of death in the first year of life.

Birth defects can be caused by genetic and environmental factors. There are also defects, the cause of which could not be determined.

Structural or metabolic defects– these are defects that manifest themselves in the incorrect formation or absence of any part of the body or organ, or in hormonal imbalance.

Metabolic defects occur in 1 in 3,500 births and are usually associated with the absence or abnormal structure of an enzyme (a protein needed to process chemicals in the body). This type of defect can be dangerous or even fatal, but usually does not cause any visible abnormalities in the child. Metabolic defect is also considered Tay-Sachs disease, a fatal disease that affects the central nervous system, and phenylketonuria, a disease associated with pathology of phenylalanine hydroxylase, which is responsible for the metabolism of phenylalanine.

Defects caused by congenital infections When the mother acquires infections before or during pregnancy, such as rubella (German measles), cytomegalovirus (CMV), syphilis, toxoplasmosis, Venezuelan equine encephalitis, parvovirus, and, less commonly, chickenpox can lead to congenital abnormalities in the infant.

Other causes of birth defects include alcohol abuse, adverse effects of environmental factors during pregnancy, and differences between the Rh factor of the mother and child.

Also, exposure to some drugs can cause birth defects, but none of the 200 most commonly used drugs poses such a threat.

Causes

Most children with birth defects are born to parents without obvious health problems or risk factors. A woman can follow all the recommendations of an obstetrician, however, even in this case, the child may be born with some kind of pathology.

About 60% of birth defects occur for reasons unknown to doctors. The rest are caused by environmental or genetic factors or a combination of both.

Genetics plays a role in some birth defects. Every cell in the body contains genes that contain chromosomes that determine the unique characteristics of an individual. The absence of one gene or its mutation can lead to birth defects. And this is significant when you consider that each of us has about 25,000 genes in our cells, which determine everything from the length of our fingers to the color of our eyes.

Where do defective genes come from? A child inherits one of each pair of chromosomes (and one of each pair of genes) from each parent. Sometimes a disease or defect can occur if one parent is infected (even if the child inherits a healthy gene from the other parent). This is called dominant inheritance and includes birth defects such as Achondroplasia (a form of dwarfism) and Marfan syndrome (a condition characterized by abnormally long fingers and toes).

Some birth defects only occur if both parents (being healthy) are heterozygous carriers of the mutation that they both passed on to their child, i.e. The sick child inherits one of the mutations from his mother, and another, exactly the same, from his father. This is called recessive inheritance. Among the defects that develop in this way are Tay-Sachs disease and cystic fibrosis.

Finally, some boys inherit disorders from genes passed on to them by their mothers. These defects include hemophilia and color blindness.

The number and structure of chromosomes also matter. A mutation in an egg or sperm can damage the baby's chromosomes or produce the wrong number of chromosomes. Birth defects caused by such abnormalities include Down syndrome. The risk of this type of birth defect increases with the age of the mother.

Birth defects are most often caused by maternal health, exposure to chemicals (drugs), or disease. If a mother gets rubella during pregnancy, it can lead to birth defects. Alcohol abuse can cause fetal alcohol syndrome, and some medications taken by the mother during pregnancy can cause abnormalities.

Multifactorial defects can be caused by a combination of genetic and environmental factors. These include neural tube defects and cleft lip and/or palate.

Some common birth defects

Cleft lip and/or palate occurs when the tissues of the mouth and lips do not form correctly during fetal development. A cleft lip is a long gap between the upper lip and the nose. The cleft palate is the opening between the palate and the nasal cavity.

Cerebral paralysis, usually not detected until several weeks or even months after birth, depending on the severity of the disease. The disease is characterized by damage to the motor and other centers of the brain, and is characterized by poor coordination and involuntary movements. The degree of uncontrollability depends on the extent of brain damage and can be either mild or extremely severe.

In most cases, the causes of cerebral palsy are unknown. Known causes include the following:

rubella (German measles) infection during pregnancy
Rh disease (incompatibility of Rh blood of the child and mother)
· prematurity
brain damage during the last trimester of pregnancy or at the time of birth

Cerebral paralysis may also have genetic causes or may be associated with head injuries or meningitis that occur after the baby is born. Treatments used to improve motor skills include surgery, braces, and other aids to control muscle movement.

Clubfoot is a term used to refer to a group of structural defects of the foot and ankle in which the bones, joints, muscles, and blood vessels do not form correctly. These defects can be mild or severe and can affect one or both legs.

It is a relatively common birth defect, occurring approximately 1 in 735 births in the United States. Boys suffer from this defect almost twice as often as girls. The cause is unknown, but the disease is treated with casting. This treatment is effective in 95% of cases; if this does not happen, a surgical method is used to correct the defect.

Congenital hip dislocation occurs due to disruption of the normal development of the elements of the hip joint during intrauterine development. As a rule, this deviation is more common in girls. Usually, this defect is detected at birth, and treatment begins immediately. A splint is individually selected for the child, which allows him to hold his legs in a position of flexion in the hip and knee joints, which contributes to their proper development. Treatment lasts 6-9 months. If such treatment does not produce positive results, surgical methods are used.

Congenital hypothyroidism occurs approximately once in 3000 - 4000 births, and is characterized by a decrease in thyroid function. This causes the gland to produce insufficient thyroid hormone, which is important for supporting normal growth and brain development.

If this defect is not treated within the first few weeks of life, it can lead to developmental delays and mental retardation.

Fetal alcohol syndrome (FAS) characterized by slow growth, mental retardation, specific features of the facial structure, problems with the central nervous system. EAS cannot be cured, but can be prevented by avoiding alcohol consumption during pregnancy.

Neural tube defect (NTD) develops during the first month of pregnancy, when the structure of the brain and spinal cord is formed. As a rule, the formation of the primary neural tube occurs on the 29th day after conception. When the tube does not close completely, the baby develops NTDs, and many babies with these defects are stillborn or die shortly after birth.

The two most common forms of NTDs are:

• Spina bifida develops when the part of the neural tube that forms the spinal cord does not close completely during the first months of pregnancy. It varies from moderate to severe, and in the most severe cases the child dies.
• Anencephaly- a severe brain defect that occurs with a frequency of 3 times per 10,000 births, and involves the absence of the cerebral hemispheres, cranial vault bones and soft tissues.

Research has shown that many of these defects can be prevented if the mother gets enough folic acid before and during pregnancy, especially during the first trimester.

Women during pregnancy should carefully monitor their diet and ensure that it contains folic acid, which greatly contributes to the normal development of the spine; it can be taken not only through food, but also through medications. Folic acid is recommended for women throughout their reproductive years.

Heart defects

Heart defects occur when any part of the heart does not develop properly.

For example:

· Atrial and interventricular septal defects characterized by the presence of communication between the right and left parts of the heart at the level of the ventricles.

· Patent ductus arteriosus, which provides the so-called embryonic type of blood circulation, in which the fetal lungs are excluded from the circulatory system. When this anomaly develops, the duct does not close after birth as expected.

· Aortic or pulmonary valve stenosis- abnormal narrowing in the area of ​​the aortic valve, impeding flow from the heart to other organs.

· Coarctation of the aorta– congenital narrowing of a section of the aorta up to complete closure of its lumen.

· Transposition of the great vessels- a congenital heart defect in which the aorta comes from the right ventricle, and the pulmonary artery comes from the left.

· Hypoplasia of the left heart characterized by underdevelopment of the left chambers of the heart, atresia or stenosis of the aortic and/or mitral orifice and hypoplasia of the ascending aorta.

· Tetralogy of Fallot is a combination of four heart defects that restrict the flow of blood to the lungs (narrowing of the pulmonary artery).

These defects are among the most common defects, occurring with an frequency of 1 in 100 births. The specific cause of most heart defects is not known, but several factors are known that can alter the development of the heart in the first 8 to 9 weeks after conception.

Exposure to certain medications (such as anticonvulsants: phenytoin, thalidomide, and chemotherapy drugs) during the first trimester of pregnancy may play a role in the development of heart defects. Other causes may include alcohol abuse, rubella and diabetes during pregnancy.

Defects of the gastrointestinal tract

Gastrointestinal defects are structural abnormalities that can occur anywhere along the gastrointestinal tract, which consists of the esophagus, stomach, small and large intestines, rectum and anus. Incomplete or abnormal development of any of these organs can cause obstruction.

Some of these vices:

· esophageal atresia, or incomplete development of the esophagus

· diaphragmatic hernia, a defect in the muscle layer separating the chest and abdomen provokes the movement of abdominal organs into the chest

· congenital hypertrophic pyloric stenosis– development of a sharp narrowing of the lumen of the pyloric canal, resulting in constant vomiting and metabolic disorders.

· Hirschsprung's disease– an abnormality in which one part of the large intestine lacks the nerves that control contractions, resulting in severe constipation and sometimes intestinal obstruction

· gastroschisis intrauterine eventration of internal organs through a small defect located to the right of the umbilical cord.

· anal atresia suggests the absence or incomplete development of the anus, location in the wrong place

· biliary atresia(especially intrahepatic) is characterized by underdevelopment or abnormal development.

The incidence of these disorders varies from 1 in 32,000 births to 1 in 10,000 births. Genetics plays a role in all of these defects, but the extent of its influence is not known. Early detection and treatment of these defects is important because if left untreated, they can lead to serious health problems and even death. As a rule, surgical method is used to eliminate these defects.

Genetic birth defects

Cystic fibrosis (CF) is a disease affecting mainly the respiratory and digestive systems. The inability to remove chloride from the cells of organs such as the lungs and pancreas provokes the formation of thick, sticky mucus. Children with cystic fibrosis may have problems breathing and digesting food; Symptoms include chronic respiratory disease and pneumonia, loose stools and being underweight.

This genetic defect occurs with a frequency of 1 in 4 newborns when both parents are carriers of the gene with the disease. Treatment includes therapy to control the infection, maintenance of lung function, and appropriate nutrition.

Down syndrome- a group of disorders that occur in children who are born with an extra copy of chromosomes (trisomy 21). Children with this syndrome have mental retardation and distinctive facial features and other physical abnormalities; these problems are often accompanied by heart defects and other health problems.

The severity of symptoms varies, as does the degree of mental retardation. Down syndrome is a relatively common birth defect, occurring in 1 in 800 or 1000 births. The likelihood of having a child with Down syndrome increases sharply as the mother ages; The frequency of births of children with this syndrome in women after 35 years of age is 1 in 350 births, and in women after 45 years it is 1 in 30 cases.

Although some health problems caused by Down syndrome (such as heart defects) are treatable, there is no cure for the syndrome itself.

Fragile X Syndrome characterized by mental disorders, mental retardation, autistic behavior, problems with concentration and hyperactivity. Physical characteristics of children with fragile X syndrome include a long face, large ears, flat feet, and extremely flexible joints, especially the finger joints.

Boys are affected more often than girls and are more likely to have mental retardation. Both boys and girls can have emotional and behavioral problems. Recent research shows that fragile X syndrome affects approximately 1 in 2,000 male births and 1 in 4,000 female births of all races and ethnicities.

There is no drug treatment for this syndrome, but scientists are working to solve the problem by trying to prevent it through gene therapy.

Phenylketonuria (PKU) one of the forms of inherited defects in amino acid metabolism that can lead to mental retardation. A child born with phenylketonuria appears normal, but if the disease is not diagnosed and treated promptly, the child will develop developmental delays called mental retardation.

This genetic disorder occurs when both parents are carriers of the gene. The chance of inheritance is 1 in 4. Fortunately, this disease is usually detected within a few days of birth after a blood test. If the child is provided with timely treatment and a special diet, developmental delays can be prevented.

Sickle cell anemia– a disease characterized by impaired synthesis of red blood cells, which leads to chronic anemia (low blood count), periodic attacks of pain, and other health problems. This disease is genetic; if both parents are carriers of the gene, their child has a 1 in 4 chance of developing the disease.

Treatment for sickle cell disease may include antibiotics to prevent infection, blood transfusions, and a bone marrow transplant.

Tay-Sachs disease affects the central nervous system, causing blindness, dementia, paralysis, seizures, and deafness. The disease ends in death at the age of 5-6 years.

This genetic disease most often occurs in Jews from Central or Eastern Europe, when both parents are carriers, the chance of inheriting the disease is 1 in 4. Although there is no cure for this disease, there is a test that can determine whether future parents are carriers of the gene .

Infections that cause birth defects

The following infectious diseases suffered during pregnancy can lead to various birth defects:

Congenital rubella(infections during pregnancy pose a high risk to the fetus) – a birth defect that can lead to hearing loss, heart defects, mental retardation and cerebral palsy.

Toxoplasmosis- Infection of the mother with this disease can lead to various eye infections that threaten vision, hearing problems, enlarged liver and spleen, mental retardation and cerebral palsy in the infant.

Genital herpes virus- Infection in the mother can cause brain damage, cerebral palsy, vision or hearing problems, and even death of the baby if the virus is passed on to the baby before or during birth.

Congenital chickenpox– maternal infection can cause chickenpox in the newborn and lead to scarring, muscle and bone defects, abnormal development and paralysis of limbs, blindness, seizures and mental retardation.

Talk to your doctor about ways to prevent these infections during pregnancy, and what you should do if you are already infected.

Diagnosis of congenital defects

Routine prenatal screening can do two important things: help determine whether the mother has an infection or any other conditions that could pose a risk to the fetus and also determine whether the fetus has any developmental abnormalities.

Defects that can be determined using prenatal examination:

Neural tube defects (spina bifida, anencephaly)
Down syndrome
· Other chromosomal abnormalities
Inherited metabolic disorders
· Internal heart defects
· Malformations in the development of the gastrointestinal tract and kidneys
· Cleft lip and/or palate
Some congenital limb defects
· Internal tumors

It is important to remember that screening only detects possible abnormalities. It is likely that the child will be born healthy, even after the results of the study showed that he has some defects. You don't have to be screened at all; Ask your doctor to explain the recommended tests to you.

After birth, your baby will be screened (with your permission) for certain birth defects according to established guidelines. Which defects your baby will be tested for will depend on his condition.

If you have concerns about a specific birth defect, you may want to have your baby tested while she is in the womb. Talk to your pediatrician before your baby is born.

Is it possible to avoid birth defects?

Many birth defects can be avoided; however, you will need to take precautions before and during pregnancy.

Before pregnancy: Women planning a pregnancy should ensure that they do not have any sexually transmitted diseases (STDs) and that they have the recommended dose of folic acid in their daily diet.

You should avoid taking medications during pregnancy, so consult your doctor before taking any medications; It is better not to take any medications unless the issue concerns a serious health problem. And never take medications without consulting a doctor.

If you or your partner have a history of birth defects, if you already have a child with a birth defect, or if you are considered at risk (due to age, ethnicity, or medical history), talk to your health care professional about planning for a child. Your geneticist will give you advice about prenatal testing and help you address any concerns or fears you may have.

During Pregnancy: The best thing a pregnant woman can do to increase her chance of having a healthy baby is to take care of herself during pregnancy:

· Do not smoke and avoid being in places where people smoke
· Do not drink alcohol
· Do not take prohibited medications
· Eat a healthy diet and take prenatal vitamins
· Exercise and get plenty of rest
· Follow the rules of prenatal care

Talk to your doctor about other precautions you can take to protect your baby's health—don't be afraid to ask questions if you have any.

Why do some children have birth defects? Gynecologist Georgy Poghosyan talked to reporters about this.

Often the causes of birth defects are various hidden infections, which may not manifest themselves in any way, but can cause serious harm to the fetus. We are talking about viral infections, in particular cytomegalovirus and herpes.

In fact, these viruses are present in the body of almost all people. For example, about 97% of all inhabitants of the planet are infected with cytomegalovirus, since it is spread by airborne droplets and it is impossible to avoid infection. The fact is that any virus in the body is either active or in a state of “hibernation”. In the “dormant” state, the virus does not manifest itself in any way and is not dangerous, but when the virus “wakes up”, it can cause problems during pregnancy, and then the fetus may experience various defects.

What defects can these viruses cause?

The following defects may appear due to cytomegalovirus: anencephaly, absence of limbs, rabbit lip, cleft palate and others. One of the main reasons for the absence of limbs or their improper development, according to a specialist, is cytomegalovirus.

Herpes, in turn, can cause miscarriage or expulsion of the fetus at 14 weeks of pregnancy. And if there was no miscarriage and the child was born, then such children usually have problems with hearing or vision, or such children are born with Down syndrome. Of course, these problems do not arise in all cases, but they can occur.

Why virusesare activated?

According to gynecologist Georgy Pogosyan, viruses wake up due to decreased immunity, which in turn has several reasons: in particular, it can be stress and an unhealthy lifestyle.

According to the specialist, a big role is played by the fact that many young women, wanting to lose weight, go on diets and eat poorly, as a result of which the body’s resistance drops, and viruses “wake up” and can cause harm to the woman or fetus during pregnancy. As Georgy Poghosyan noted, you should not go on diets without consulting a doctor, as they can cause serious health problems in the future.

In addition, according to the specialist, in Armenia there is still no culture of undergoing a medical examination before marriage. Of course, these examinations are quite expensive. But married couples spend a lot of money on wedding celebrations, if part of this money is spent on their health and on preventive examinations, then in the future this will help them avoid many problems.

Follow on

Birth of a child- the happiest event for every married couple. The anticipation of meeting your baby is often overshadowed by anxious thoughts about his health and proper development. In most cases, the worries of young parents turn out to be in vain, but sometimes fate treats the unborn baby quite harshly: the baby receives from mom and dad not only hair color, eye shape and a sweet smile, but also various hereditary diseases.

According to medical statistics, the probability of having a child with a hereditary pathology for each expectant mother is 3–5%. For example, the probability of having children with Down syndrome is 1:700. The most difficult to diagnose and amenable to further treatment are rare, so-called orphan diseases: osteogenesis imperfecta, epidermolysis bullosa, Menkes syndrome, progeria and many others. As a rule, these genetic hereditary diseases pose a threat to the child’s life, significantly reduce its duration and quality, and lead to disability. In our country, diseases that occur with a frequency of 1:10,000 are considered “rare”.

Causes of hereditary diseases

Each cell of the human body carries a certain code contained in chromosomes. In total, humans have 46 of them: 22 of them are autosomal pairs, and the 23rd pair of chromosomes is responsible for the sex of a person. Chromosomes, in turn, consist of many genes that carry information about a certain property of the organism. The very first cell formed at conception contains 23 maternal chromosomes and the same number of paternal chromosomes. A defect in a gene or chromosome leads to genetic disorders.

There are different types of genetic disorders: single gene defect, chromosome defect and complex defect.

Single gene defect may be passed on from one or both parents. Moreover, being a carrier of a recessive gene, mom and dad may not even know about their disease. Such diseases include progeria, Menkes syndrome, epidermolysis bullosa, and osteogenesis imperfecta. A defect transmitted on chromosome 23 is called X-linked. Each person inherits an X chromosome from his mother, but from his father he can receive a Y chromosome (in this case a boy is born) or an X chromosome (a girl is born). If a defective gene is detected on a boy’s X chromosome, it cannot be balanced by a second healthy X chromosome, and therefore there is a possibility of developing a pathology. This defect can be transmitted from a mother who is a carrier of the disease or develop completely unpredictably.

Chromosome defect- change in their structure and number. Basically, such defects are formed during the formation of eggs and sperm of the parents; a chromosomal defect occurs in the embryo during the fusion of these cells. This pathology usually manifests itself in the form of serious impairments in physical and mental development.

Complex defects arise as a result of the influence of environmental factors on a gene or group of genes. The mechanism of transmission of these diseases is still not fully understood. According to doctors, the child inherits from the parent a special sensitivity to certain environmental factors, under the influence of which the disease can ultimately develop.

Diagnosis in the prenatal period

Hereditary diseases of children can be identified in the prenatal period. So, recently, in many consultations, a test that determines the level of the hormones AFP, estrogen and hCG is performed on all women between and 18 weeks of pregnancy. It helps to determine pathologies of child development due to chromosomal defects. It is worth noting that this screening allows us to identify only a part of genetic disorders, while the modern classification of hereditary diseases is a complex system that includes about two thousand diseases, conditions and syndromes.

Future parents should keep in mind that based on the results of this analysis, a specific disease is not diagnosed, but only its probability is determined and a decision is made on the need for additional examinations.

Amniocentesis- a procedure during which the doctor, using a thin and long needle, takes amniotic fluid, penetrating the woman’s uterus through the abdominal wall. Previously, the woman is sent for an ultrasound examination to determine the position of the fetus and the best place to insert the needle. Sometimes an ultrasound is performed directly during the amniocentesis procedure.

This study allows you to identify many chromosomal defects, determine the degree of development of the child’s lungs (if it is necessary to give birth before the planned date), and accurately determine the sex of the child (if there is a threat of diseases associated with a certain gender). Examination of the resulting liquid takes several weeks. The disadvantage of this procedure is that it can be performed beyond 16 weeks of pregnancy, which means that the woman has very little time to decide whether to terminate the pregnancy. Moreover, unlike the first trimester, abortion at such a long term is an extremely dangerous procedure for both the physical and mental health of a woman. The risk of spontaneous abortion after this study ranges from 0.5 to 1%.

By examining the chorion (tissue surrounding the fetus in early pregnancy), it is also possible to determine genetic disorders in the fetus, including diagnosing quite rare diseases, such as epidermolysis bullosa and osteogenesis imperfecta. During this procedure, the doctor inserts a thin tube into the woman's uterus through the vagina. Pieces of chorionic villi are sucked through the tube and then sent for analysis. This procedure is painless and can be performed as early as the 9th week of pregnancy; the results of the study will be ready in one or two days. Despite the obvious advantages, this procedure is not in great demand due to the high risk of spontaneous abortion (2–3%) and various pregnancy disorders.

Indications for chorionic villus sampling and amniocentesis are:

• the age of the expectant mother is more than 35 years;
• chromosomal defects in one or both parents;
• the birth of a child with chromosomal defects to a couple;
• expectant mothers whose families had X-linked diseases.

If the studies have confirmed the presence of a genetic disorder, parents, having weighed all the pros and cons, will have to make perhaps the most difficult choice in their lives: to continue or terminate the pregnancy, since treatment of hereditary diseases at this stage, unfortunately, is impossible.

Diagnosis after birth

Rare genetic hereditary diseases can be diagnosed based on laboratory tests. For several years now, in all maternity hospitals, on the fifth day after the birth of a baby, newborn screening has been carried out, during which a number of rare hereditary diseases are diagnosed: phenylketonuria, hypothyroidism, cystic fibrosis, galactosemia and adrenogenital syndrome.

Other diseases are diagnosed based on symptoms and signs that can appear both during the newborn period and many years after birth. Symptoms of epidermolysis bullosa and osteogenesis imperfecta in most cases appear immediately after birth, and the diagnosis of progeria is most often made only at 2–3 years of a child’s life.

It can be very difficult for an ordinary pediatrician to recognize rare diseases; the doctor may simply not notice their symptoms during a routine appointment. That is why a mother needs to be very attentive to her own child and pay attention to threatening signs: motor skills that are not appropriate for her age, the appearance of seizures, insufficient weight gain, unnatural color and smell of feces. Also, a sharp increase or slowdown in the child’s growth process should also be a cause for concern; this may indicate the presence of a disease such as dwarfism. If such symptoms appear, parents should definitely consult a doctor, insisting on a thorough examination of the child, because timely diagnosis of hereditary diseases and selection of the correct treatment program can help preserve the health, and sometimes even the life of the baby.

How are genetic diseases treated?

Although most hereditary diseases cannot be cured, modern medicine can significantly increase the life expectancy of sick children, as well as improve its quality. Today, such diseases are not a death sentence, but rather a way of life that allows the child to develop normally, provided he receives the necessary treatment: taking medications, gymnastics, special diets. Moreover, the earlier it is possible to diagnose, the more successful the treatment of hereditary diseases is.

Recently, methods of prenatal (prenatal) treatment are increasingly being used: with the help of medications and even surgical operations.

A child's illness is a difficult test for the whole family. In these conditions, it is very important for parents to support relatives and communicate with other mothers and fathers who find themselves in a similar situation. Various communities of parents with children with rare genetic diseases provide great assistance to such families.

How to prevent hereditary diseases?

Competent pregnancy planning, the main focus of which is the prevention of hereditary diseases, will help avoid the birth of a sick child. Parents at risk should definitely visit a geneticist:

• parental age −35 years and above;
• having one or more children with a hereditary disease;
• rare diseases of spouses or their close relatives;
• couples worried about having a healthy baby.

A genetic consultant, based on medical examination data, as well as information about family history, diseases that relatives suffered from, the presence of abortions and miscarriages, calculates the likelihood of having a child with a genetic disease. It happens that a couple who has a high chance of giving birth to a sick child abandons these plans in this union, and with other partners they have completely healthy children.

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It is very difficult for parents to hear that their child has been diagnosed with developmental disabilities. This information often becomes known during prenatal diagnosis. As a rule, the family experiences severe psychological shock, but what’s even worse is that parents often begin to blame themselves for what happened, not hoping that they will ever be able to give birth to a healthy child. Why do birth defects occur, and what next for children with developmental defects?

First of all, you need to know: a child with congenital defects can be born in any family, even to young and healthy parents. The frequency of these cases reaches 5% according to statistics. Identifying the causes of congenital malformations of the fetus (CHD) is one of the most important tasks of medicine, but at the same time it must be said that not all of them have been studied and classified. Up to 50% of pathologies cannot be associated with any specific cause. However, much work has already been done in this regard.

Developmental defects (anomalies, defects) are considered to be functional and structural deviations from the norm. The most severe defects include:

• Congenital heart defects;
• Neural tube defects;
• Down syndrome.

Fetal malformations: causes

All congenital malformations can be divided into two large groups: hereditary (gene mutations) and acquired during intrauterine development. Often, both of these factors can affect the occurrence of congenital malformation, and such causes are called multifactorial.

According to the severity, fetal anomalies can be classified as moderately severe (those that require treatment, but do not threaten the life of the child), severe - requiring immediate treatment, and fatal, incompatible with life.

Most congenital malformations occur during the first trimester. Gametopathies are the result of mutations in germ cells or abnormalities of sperm and eggs. Blastopathy develops during the first two weeks after fertilization. Embryopathies are the most common pathologies and occur between 2 and 8 weeks of pregnancy. Finally, fetopathy can occur after 9 weeks - for example, cryptorchidism or organ hypoplasia.

Fetal malformations can affect one organ or several at the same time. Systemic disorders include abnormalities of the respiratory system, nervous, cardiovascular, musculoskeletal, reproductive, urinary and digestive systems. Defects such as defects of the face, eyes, ears, neck, palate and lips are divided into separate groups.

Is it possible to assume in advance that the child may have congenital malformation? There are risk groups that include the following categories of parents:

• Families in which children with congenital malformations have already been born;
• Families where parents have blood relatives with congenital malformation;
• Parents' age is over 35 years for women and 50 years for men;
• Consanguinity between parents;
• Exposure to teratogenic factors (living in an environmentally unfavorable place, radiation, working in hazardous industries).

Teratogenic causes of fetal malformations are extremely extensive - there are at least four hundred of them. All parents, without exception, know about the dangers of drug addiction, alcoholism and smoking during pregnancy, but the causes of congenital malformation are not limited to these points.

One of the very dangerous exposure factors is viral diseases suffered by a woman in the first trimester of pregnancy. This is especially true for the rubella virus. Unfortunately, in some cases, the fetus may experience irreversible changes that are not life-threatening.

Taking medications (especially hormonal ones) in the first trimester can also be extremely dangerous, so doctors never tire of warning that any treatment during this period should only be carried out under the supervision of a doctor.

Endocrine disorders in the mother, including diabetes mellitus, are also at risk. Irradiation (radiation, x-rays) in some cases can cause fetal development abnormalities, and that is why such examinations in the first trimester are carried out only for health reasons and under reliable protection.

Living in an environmentally unfavorable area - near mines, metallurgical enterprises and similar places - poses a great danger to the development of a child. In addition, anomalies in the development of the fetal cardiovascular system are also found in women living in high mountains with thin air. Injuries and falls, incorrect fetal position, and the presence of tumors can affect the blood supply to the fetus and cause congenital birth defects.

Maternal nutrition can also have an impact on the occurrence of fetal malformations - for example, folic acid deficiency has been proven to increase the risk of neural tube developmental abnormalities in the child. Finally, the child’s father’s work in hazardous work can lead to sperm abnormalities, which is also one of the causes of congenital malformation.

What to do if a child has a developmental defect

We have already spoken about the shock that invariably befalls parents at this news. But you need to try to deal with it quickly - perhaps with the help of specialists. If the pathologies are incompatible with life and the timing allows for termination of the pregnancy, doctors will immediately say so.

The life of children with fetal developmental defects largely depends on the timeliness of measures taken. Today, even the most complex defects are successfully operated on, and operations are often carried out in the first days of life. A number of defects make it possible to postpone surgery or even undergo conservative treatment. Parents should try to collect the maximum amount of information about this disease in order to know all its symptoms and treatment features. Of course, such babies will be under constant medical supervision and undergo regular examinations. There are a number of dietary and physical activity restrictions that your pediatrician will tell you about.

The birth of a child with congenital developmental defects is always stunning for the family; this topic is one of the most difficult in obstetrics. At the first moment, the spouses experience an incomparable psychological shock, which then turns into a feeling of guilt; it seems to them that they will never have a healthy child.

It should be said right away that a child with congenital defects can be born into absolutely any family - young, healthy, without bad habits, with a normal pregnancy. According to long-term statistics, around the world, about 5% of children are born with congenital diseases.

Congenital malformations of the fetus can be divided into two large groups - hereditary (that is, embedded in genes and chromosomes, transmitted by inheritance) and actually congenital (acquired during intrauterine development). This division is quite arbitrary, since most developmental defects are caused by a combination of hereditary predisposition and adverse external influences, representing multifactorial anomalies.

The problem of congenital malformations of the fetus is very diverse; various specialists study this issue - geneticists, neonatologists, embryologists, and specialists in prenatal (prenatal) diagnostics. Understanding the reasons is always difficult.

Hereditary diseases

Mutations are the basis of hereditary diseases. Thanks to modern blood-curdling thrillers, this word now evokes almost superstitious horror in many. In fact, the Latin word mutatio means “change” - nothing more. A mutation is a change in the hereditary properties of an organism as a result of rearrangements in the structures responsible for the storage and transmission of genetic information. Diseases associated with pathological changes in chromosomes are usually called chromosomal diseases. Under actual hereditary diseases understand disorders caused by gene mutations.

Table 1 below lists, by way of example, just some of the life-threatening hereditary anomalies.

Congenital multifactorial malformations

Congenital malformations are very diverse; they can affect almost any organ of the fetus. Their occurrence is caused by various adverse effects on the fetal organs, especially in the early stages of pregnancy. Factors that cause fetal malformations are called teratogenic. The most studied types of teratogenic effects are the following:

• Ionizing radiation (X-rays, exposure to radioactive isotopes). In addition to the direct effect on the genetic apparatus, ionizing radiation has a toxic effect and is the cause of many congenital anomalies.
• Teratogenic infections , i.e. infectious diseases transmitted from mother to fetus.
• Medicines . There are no medications that can be unconditionally recognized as completely safe, especially in the early stages of pregnancy. During pregnancy, medications should be taken only as prescribed by the attending physician and taking into account their possible effect on the fetus. (See S. Gonchar “Medicines and Pregnancy” in this issue of the journal. - Approx. ed.) You should not go to the other extreme and not treat follicular tonsillitis or a carious tooth just because “the pills are harmful for a pregnant woman.” It’s good for the fetus if the mother feels good!
• Alcohol . Drinking alcohol in large doses by a pregnant woman can lead to the development of fetal (i.e., affecting the fetus) alcohol syndrome - a severe congenital disease, sometimes incompatible with life. But you shouldn’t exaggerate the risk - a glass of champagne drunk before conception is not at all a reason to terminate a pregnancy! If you are concerned about the risk of “drunk conception,” be sure to consult a geneticist.
• Nicotine . Smoking a large number of cigarettes during pregnancy leads to retarded physical development of the child.
• Exposure to toxic chemicals . Women who have contact with active chemicals due to their work should plan pregnancy. 2-3 months before conception and the entire period of pregnancy (especially up to 14-16 weeks), it is advisable to avoid contact with chemicals that can cause a teratogenic effect in the fetus.

Often, however, a factor such as hereditary predisposition plays a role in the development of congenital defects: it is known that if parents or close relatives had congenital malformations, then the risk of giving birth to a child with similar defects increases, that is, we are talking about a “family accumulation” of anomalies development. Thus, a woman with a congenital heart defect has a slightly higher chance of giving birth to a child with a defect in the development of the cardiovascular system than all other women. Therefore, it is customary to talk not so much about simply congenital, but about congenital multifactorial malformations . However, a large amount of statistical material shows that the repeated risk of having a child with a congenital malformation is small - on average 2-4%. Let us give several examples of congenital multifactorial malformations compatible with life (see. Table 2).

I would like to emphasize once again that when it comes to congenital malformations, the question “who is to blame?” often remains unanswered, it is more productive to look for an answer to the question “what to do?” Let's talk about this topic.

What to do, if…

1. You are planning a pregnancy

It is known that the “risk group” from the point of view of the birth of offspring with congenital diseases includes:

• men and women in whose families one or another hereditary disease has already occurred, even if they themselves are not sick;
• families where there are already children suffering from congenital malformations;
• families in which previous pregnancies ended in miscarriages or stillbirths;
• spouses who are related (for example, first and second cousins);
• women over 35 and men over 50;
• men and women who, due to their occupation, health status or for some other reason, are exposed to the teratogenic factors listed above.

In all these cases, we strongly recommend that partners planning pregnancy attend a medical genetic consultation. Geneticists will draw up a pedigree and determine the risk of having a child with a hereditary disease. The current level of development of medical technologies allows today, in case of an unfavorable prognosis, to resort to artificial insemination with donor sperm or fertilization of a donor egg. In addition, exposure to teratogenic factors should be eliminated or minimized whenever possible.

2. You are expecting a baby

and are part of one of the listed “risk groups”. The first step in this case should be a visit to a medical genetic consultation. It's not fun to talk about, but there are - although very rare - situations when, based on pedigree genetics alone, they come to the conclusion that the fetus is affected by a disease incompatible with life. In this case, of course, termination of pregnancy is recommended. However, we repeat, these cases are very, very rare. As a rule, specialists in medical genetic consultation do not engage in diagnosis, but in assessing the risk of having a child with severe anomalies and, based on this assessment, recommend one or another method of prenatal diagnosis. Further, the decision is made depending on the results of the study. Only a specialist can decide how high the risk of giving birth to a child with developmental defects really is. Do not rush to have an abortion if you read in the annotation that the drug you took at the very beginning of pregnancy is not recommended for use during this period; if you took alcohol, drugs or suffered an acute respiratory viral infection, took an x-ray during pregnancy, etc. Be sure to contact a medical genetic consultation, where they will be able to correctly assess the real risk and recommend the necessary set of studies.

3. You had a child with a congenital malformation

The best way to cope with psychological shock is to try to obtain maximum information about the nature of the developmental defects. Make sure your child is consulted by a geneticist. It is highly desirable that a sick child undergo a cytogenetic study (analysis of the karyotype - a set of chromosome characteristics). The more information about a sick child is obtained, the more effective the treatment will be and the more accurately it will be possible to establish a prognosis for the future. It is better to seek final medical and genetic consultation regarding the prognosis for the future after 2-3 months, when psychological tension has subsided and the spouses will be able to perceive this kind of information more objectively. For most families, subsequent pregnancies are successful. The possibilities of prenatal diagnosis add confidence in a successful outcome for both doctors and patients.