The influence of environmental factors on human embryogenesis. Teratogenic factors. Embryotoxic effect. Effect of drugs on the embryo and fetus Other harmful environmental factors

From the first moments of life until the very last minute, the human body interacts with the external environment. This interaction is a necessary condition for the normal growth and development of a person.

Under the influence of almost any influence, changes in the internal environment of the body occur to a greater or lesser extent, and all its known reactions are aimed at maintaining or equalizing its parameters. They are called adaptive-compensatory reactions(adaptation- from lat. adaptation, addiction), which are based on adaptive-compensatory mechanisms. If the intensity or aggressiveness of the factor does not go beyond the limits of adaptive-compensatory reactions, the body copes without much damage. With prolonged exposure, these mechanisms are destroyed and the disease develops.

External environment as an integral system includes a large number of different elements or factors that differ from each other in quantitative and qualitative terms.

Physical factors. To physical factors include all types electromagnetic vibrations natural or artificial origin.

The most powerful natural source of electromagnetic vibrations in nature is the Sun. It is thanks to solar energy that all biological processes on Earth occur. The wavelength range of solar radiation extends from a few fractions of a nm (gamma radiation) to meter-long radio waves.

Of all solar radiation in the visible range, the most powerful biological effect is ultraviolet radiation. It has a pronounced erythemal effect, i.e. it causes redness of human skin with subsequent formation of pigment. This is nothing more than a protective reaction of the body from overheating. Thus, direct exposure to ultraviolet radiation on a living organism is far from safe.

Natural natural sources of EMF can be divided into two groups. The first includes constant Earth's electric and magnetic fields, to the second - radio waves, generated by cosmic sources (Sun, stars), as well as electrical processes in the atmosphere, such as lightning strikes. The frequency range varies widely.

Different people react differently to EMFs because they have different sensitivity to them. Some people do not notice magnetic storms at all, while others, on the contrary, feel even minor changes in electromagnetic fields.

Artificial sources electromagnetic radiation are radio stations, radar stations, high-voltage power lines and many others transmitting technical means. They emit energy in a very wide range of wavelengths - from millimeters to several tens and hundreds of meters. Particularly strong effects are observed near radiation sources.

Chemical factors. Chemicals are widely used by humans in production and in everyday life (preservatives, washing, cleaning, disinfectants, as well as products for painting and gluing various objects).

All chemicals used in everyday life, in small quantities are safe for health. However, violating the rules for their use can have an adverse effect on the body.

Chemicals should also include medicines, which are prescribed by doctors for various diseases. Many modern medicines come in the form of multi-colored dragees and have a very attractive appearance, so children often confuse them with candies. Meanwhile, one tablet is enough to cause serious poisoning in a child, life-threatening.

Biological factors. The forms of existence of living matter on Earth are extremely diverse: from single-celled protozoa to highly organized biological organisms. All known microorganisms can be divided into three groups: completely safe for humans(saprophytes), we are constantly in contact with them, but this never causes diseases; definitely harmful that is, dangerous to human health (meeting with them is always fraught with the development of an infectious disease, however, this happens when the body does not have appropriate protection); conditionally pathogenic(these are microorganisms that under normal conditions do not cause any diseases in humans, however, when the body is weakened due to a cold or chronic disease, malnutrition, vitamin deficiency, stress, fatigue, etc., they can cause diseases). Group selected especially dangerous microorganisms that cause severe diseases in humans. These are, for example, the causative agents of smallpox, plague, cholera, tularemia, anthrax, and polio.

Social factors. Social factors are associated with people's lives, with their attitude towards each other and towards society. Revolutionary changes almost always cause social tension in society, which can have a negative impact on the individual and society as a whole. And on the contrary, the calm, progressive, evolutionary development of society and social relations guarantees a calm, creative environment and a reduction in the influence of factors of social nature on human health.

Mental factors. Environmental factors that have a mental connotation are associated with a specific aspect of human life. A person’s behavior in various situations, his perception of the surrounding reality, its emotional coloring, the nature of a person’s behavior in a given situation, the formation of his personality are closely related to factors of the external and internal environment and their interaction with each other.

The implementation of the ideas of mental and social health will require each person to rethink such personal qualities as activity and responsibility, and for society to reconsider established priorities and traditions in the field of upbringing and education, work and leisure.

Critical periods of development. One of the main patterns of development is heterochrony - the formation of organ anlages at different times and the different intensity of their development.

The first critical period is at the beginning or in the middle of crushing;

The second is at the beginning of gastrulation;

The third coincides with the formation of the rudiments of all organs.

Implantation (6-7 days after conception)

Placentation (end of 2 weeks of pregnancy)

Perinatal (childbirth)

At these stages, the embryo is especially sensitive to a lack of oxygen, high or low temperature, mechanical stress, etc. During critical periods, the embryo's metabolism changes greatly, respiration increases sharply, the RNA content changes, and new, previously absent proteins are immunologically detected. At the same time, the growth rate is falling. Critical periods coincide with active morphological differentiation, with the transition from one period of development to another, with a change in the conditions of existence of the embryo. (transition of the zygote to fragmentation, the onset of gastrulation, implantation of the blastocyst into the uterine wall (in mammals)). The critical period in the newborn’s body is associated with a sharp change in living conditions and restructuring in the activities of all body systems.

Teratogenesis- the occurrence of malformations under the influence of environmental factors (teratogenic factors) or as a result of hereditary diseases.

Teratogenic factors include medicines, drugs and many other substances. The effect of teratogenic factors is dose-dependent. The dose dependence of teratogenic effects may vary among different species. For each teratogenic factor there is a certain threshold dose of teratogenic action. Usually it is 1-3 orders of magnitude lower than lethal. Differences in teratogenic effects in different biological species, as well as in different representatives of the same species, are associated with the characteristics of absorption, metabolism, and the ability of the substance to spread in the body and penetrate the placenta. Sensitivity to various teratogenic factors may change during fetal development. In cases where infectious agents have a teratogenic effect, the threshold dose and dose-dependent nature of the action of the teratogenic factor cannot be assessed.

Major developmental defects
Malformations of the central nervous system

Malformations of the central nervous system are classified as polygenic diseases.

Certain toxic substances, when entering the body of animals along with food or as a result of treatments, can negatively affect the reproductive function of animals, causing embryotoxic, teratogenic, and gonadotoxic effects. For this reason, toxic substances that can be ingested by animals continuously or over a period of time should be tested for embryotoxicity, teratogenicity and gonadotoxicity. It is also advisable to test certain medications and premixes for these effects if they are used repeatedly.

Embryotoxic effect. This is the ability of the test substance to have a negative effect on developing embryos. In medical toxicology, the embryotoxic effect is studied on female white rats, which are administered orally through a tube or given the drug with food throughout pregnancy. On the 17-19th day of pregnancy, the beginning of which is determined by the results of a study of vaginal smears, rats are killed, the number of fetal sacs, corpus luteum in the ovaries, live and dead fetuses is counted. By comparing the results of these studies in the experimental and control groups, the degree of embryotoxic activity of the drug is determined. Some of the pregnant rats from the experimental groups are left for childbirth, while taking into account the duration of pregnancy, the number of fetuses, their weight, the length of the body of newborn rat pups, their development (increase in length and weight over a certain period, the time of opening of the eyes, covering with hair, the beginning of independent movement around the cage and eating food). In addition, the survival rate of rat pups and their distribution by sex are taken into account. At the same time, they note: selective embryotoxicity - the effect manifests itself in doses that are not toxic to the maternal body; general embryotoxicity - manifests itself simultaneously with the development of intoxication of the mother’s body; absence of embryotoxicity - the effect is not observed with signs of intoxication of the maternal body (Medved, 1968).

There are no methodological approaches to determining the embryotoxic properties of veterinary drugs.

In the first stages, it seems advisable to also use white rats as a model, since experiments on farm animals are difficult due to the long gestation period and the relatively small number of individuals in the litter (with the exception of pigs). If it is established that the compounds under study have general or selective embryotoxicity, experiments are carried out on animals, and primarily on pigs. Depending on their intended purpose and method of administration, it is advisable to give the drugs with food, administer intramuscularly or apply cutaneously.

Teratogenic effect. This is an action that disrupts the formation of the fetus during its embryonic development. It manifests itself in the form of deformities. Teratology as a science developed after the cases of thalidomide, a drug widely used by pregnant women in Western Europe as a sleeping pill and sedative. As a result, the birth of children with congenital malformations was recorded.

In medical toxicology, the teratogenic effect of pesticides is determined on white rats. For this purpose, the drug is administered orally to animals every 1 day throughout pregnancy. Some animals in the experimental groups are killed on the 17-20th day of pregnancy, while others are left until birth. When opening dead rats, the average number of corpora lutea per female, normally and abnormally developing embryos, as well as resorbed fetuses is determined.

During natural childbirth, the number of females who gave birth, the offspring born, including stillborns, are taken into account, the average weight of the offspring, the length of the body, limbs and other morphological features are established (Medved, 1969).

The teratogenic effect of drugs on farm animals has not been studied.

When a teratogenic effect occurs, the following deformities are possible: absence of the brain (anencephaly); underdevelopment of the brain (microcephaly); increased content of cerebrospinal fluid in the ventricles of the brain (hydrocephalus); cerebral hernia (encephalocelia); splitting of the first vertebral arches (spina bifida). In addition, abnormalities in other organs are possible: absence of eyes (anophthalmia); having one eye (cyclopia); cleft lip; cleft palate; absence of limbs (peramily); absence of a tail; shortening of the tail, etc.

Gonadotoxic effect. When studying the gonadotoxic effect, the effect of the drug under study is determined separately on the genital area of females and males. Experiments are carried out on white rats. The effect of the drug on the astral cycle and oogenesis is studied in females, and on motility, morphology, sperm resistance and spermatogenesis in males.

The estrous cycle is determined by examining vaginal smears. To do this, use an eye dropper to inject a warmed saline solution (2-3 drops) into the vagina, pass it through the pipette several times, and then inject it back into the vagina. After this procedure, vaginal smears are prepared using glass slides, fixed over a flame and stained for 1 minute with a 1% aqueous solution of methylene blue. The smear is viewed under a microscope at low magnification.

The following main stages of the estrous cycle are distinguished:

The proestrus (pre-estrus) phase lasts several hours and is characterized by a predominance of epithelial cells in smears;

The estrus (estrus) phase lasts 1-2 days. At this stage, mostly keratinized polygonal cells (scales) are present;

Metestrus (after-leak) lasts 1-2 days and is characterized by the presence of epithelial cells and leukocytes along with scales;

The diestrus phase (resting phase between heats) is characterized by the presence of leukocytes and mucus. The duration of this phase is equal to half of the entire cycle.

Changes in the duration of the stages of the estrous cycle or the nature of the cells at its various stages are an indicator of the effect of the test substance.

To study the effect of a chemical on oogenesis, histological sections are prepared from the ovaries and the stages of follicle development are determined in the experimental and control groups of animals.

When studying the gonadotoxic effect of drugs on males, the ratio of motile and immobile forms of sperm, the presence of pathological forms, their resistance and the phases of spermatogenesis are determined (Medved, 1969).

Mutagenic effect. Some chemicals disrupt the transfer of genetic information, as a result of which mutants may appear - individuals with characteristics not characteristic of a given species. Therefore, the study of the mutagenic properties of pesticides and other chemicals is one of the necessary stages of toxicological research. In a number of countries, a screening test is used for this purpose - the Ames test. Individual strains of bacteria from the Salmonella group, which are highly sensitive to chemical mutants, are used as test organisms. In the presence of potential mutagenicity in the chemical substance being studied, genes are split and the number of colonies on a solid nutrient medium increases sharply. However, the mutagenicity of a chemical substance detected using this test cannot be considered absolute, since higher animals have powerful defense systems that protect the cells responsible for the transmission of genetic information from the effects of external factors, including chemicals. In many cases, the chemical can be detoxified by enzyme systems before it reaches its target.

Causes

The following reasons may cause complications caused by taking medications:

physicochemical composition of the drug;
senile or childhood age of the recipient;
the formation of decay products of toxic substances that poison the body;
weak general condition of the patient;
Exceeding the dosage or taking the drug incorrectly;
combination of drugs with incompatible pharmacological properties;
individual intolerance to one of the components of the drug, dysbiosis or allergy;
taking illegal medications during pregnancy and breastfeeding.

The toxic effect of drugs, as a rule, spreads selectively, affecting individual organs and tissues of the body. However, its acute phase can trigger the launch of irreversible processes in several systems simultaneously.

Mechanism of action

Almost every medicinal substance (DS) causes side effects, but not all of them manifest themselves. Reactions disappear after discontinuation of the drug. However, there is a risk for the patient to develop a “drug-induced disease.”

Two main aspects that help avoid serious consequences are compliance with medical prescriptions and following the instructions for the drug.

The mechanism of toxic action is such that the time range from the moment of taking the drug to the appearance of side effects has no clear boundaries. They can reveal themselves immediately after taking the medicine, or after several weeks, months and even years. Acute toxic effects manifest themselves sharply and in the shortest possible time. Most often, it is the patient’s liver and kidneys that suffer, since these organs are involved in filtering and removing decay products of poisons and harmful substances. Excessive stress can lead to complete dysfunction.

Embryotoxic effect

During the gestational period, the forces and resources of the mother's body are completely directed towards the development of the fetus. Although a pregnant woman and an embryo have different blood supply systems, it receives nutrition through the umbilical cord and all substances that enter the mother’s body are transported to the child. Such a concept as embryotoxic effect implies abnormal development of the fetus as a result of taking drugs prohibited during pregnancy and occurs in the first trimester.

Before the fertilized egg attaches to the placenta (the first 1-3 weeks after fertilization of the egg), medications affect its development in the lumen of the fallopian tubes and the process of its movement into the uterus. This action threatens the appearance of various deformities in the newborn. Among the drugs that can have a greater negative impact on the embryo are antimetabolites and antimycotics: colchicine, fluorouracil, mercaptopurine.

Teratogenic effect

From the beginning of the second month of pregnancy until its end, there is a teratogenic effect. It is at the end of the eight-week period from the beginning of gestation that the fetus develops the skeleton and develops internal organs. Its tissues at this moment are very sensitive to the effects of external negative factors. Congenital deformities in the form of skeletal developmental anomalies or organ failure are a consequence of the teratogenic effect of drugs that the mother took during pregnancy.

It was found that after taking strong sleeping pills and tranquilizing drugs, such as thalidomed, the child was born with improperly developed limbs shaped like flippers. Antitumor drugs and alcohol entering the female body during conception can also have a teratogenic toxic effect.

Fetotoxic effect

When pregnancy reaches 20 weeks, at this stage all systems and organs are already formed and function in the same way as in an adult. During this period, due to the use of medications, the unborn child is affected by fetotoxic effects. Anticoagulants affect the hematopoietic system, inhibiting the function of blood clotting. Sleeping pills and strong sedatives negatively affect the central nervous system. The use of ethyl alcohol, even as part of medicines, in small quantities and narcotic substances also cause reactions from the central nervous system and can lead to the development of cerebral palsy.

Mutagenic effect

Medicinal substances can have a mutagenic effect, manifested by a change in genetic information in the germ cells of both sexes and at the stage of cellular formation of the embryo.

Carcinogenic effect

The carcinogenic effect lies in the ability of the drug to cause the destruction of cells in the recipient and their absorption by neighboring tissues, which leads to the formation of malignant tumors.

Precautions

Considering that the toxic effect of drugs can cause irreparable harm, the prescription of any drugs to a pregnant woman should be carried out by an obstetrician-gynecologist. This does not mean at all that nothing can be accepted in the situation. In order to avoid serious consequences, you should carefully study the instructions and composition of the product and adequately assess the ratio of benefit to the mother/risk to the fetus.

Mild herbal sedatives, vitamin complexes and folic acid can be taken during this period . However, medication should be taken under close medical supervision. An important aspect is monitoring the condition of the expectant mother and the development of the fetus using blood and urine tests.

Modern pharmacology introduces only those drugs that are not capable of having embryotoxic, teratogenic, fetotoxic, mutagenic and carcinogenic effects on the human body and on the child inside the womb.

Allergy and dysbiosis

Dysbiosis

Violation of the composition of natural microflora is also a manifestation of toxic effects. Dysbacteriosis (dysbiosis) is a lack of beneficial bacteria in the intestines, mouth and vagina, which is replaced by pathogenic and fungal organisms. This phenomenon is a consequence of taking antibiotics and certain hormonal drugs.

Toxic effects due to dysbiosis are manifested in the following reactions:

from the gastrointestinal tract: frequent loose stools, abdominal cramps and pain, bloating and flatulence;
from the female reproductive system: vaginal candidiasis, the distinctive symptoms of which are itching and white curdled discharge from the vagina;
in case of violation of the microflora of the oral cavity: stomatitis, ulcers and wounds on the gums and palate, thrush on the tongue, increased body temperature, unpleasant odor.

To prevent such reactions, antibiotics are combined with antifungal agents (nystatin, pimafucin) and probiotics and prebiotics (bifidumbacterin, lacidophil, etc.).

Allergic reactions due to toxic effects occur against the background of the perception of drug components as antigens. The dosage in this case does not play a role and the severity of side effects varies: it can be skin rashes and anaphylaxis.

There are four types of allergic reactions:

Instant. Develops within several hours after taking a toxic drug. The dosage may be minimal. Immunoglobulins E react with antigens, which leads to the release of histamine. Manifestations of toxic effects can be very different: skin itching, swelling, rashes, runny nose, lacrimation, swelling of the throat and anaphylaxis. Antibiotics of the penicillin series can provoke an immediate reaction.
Cytotoxic. A nonspecific cell reaction caused by the production of IgG and IgM antibodies to determinants. Allergens are one's own tissues modified under the influence of drugs. Hematological diseases due to such exposure can be caused by antihypertensive drugs, sulfonamides, and antibiotics.
Immunocomplex. This is the result of the combined action of the allergen with IgM, IgE and IgG. The victim develops allergic alveolitis and serum sickness, the symptoms of which are itching, urticaria, and fever. This effect can be observed after taking penicillin and sulfonamide.
Delayed. These are skin manifestations that occur after the drug in the form of a cream, ointment, emulsion or suspension comes into contact with the skin. In addition, delayed onset of allergies may be the result of an organ transplant or rheumatism. In this case, there is no early phase; the immune system reaction immediately occurs, caused by lymphocytes and microphages.

The only way to prevent an allergy is to not take medications that cause it, and to warn your doctor about the development of an allergic reaction to a particular drug. If you are taking the medicine for the first time in your life, you should first inject it under the skin or smear it on a small area on the back of the forearm and see the result.

The toxic effect of drugs most often occurs during an overdose. Individual reactions to drugs used in medical practice occur less frequently, and allergies are usually provoked by paracetamol and penicillin. It is impossible to predict what response will follow when taking a particular drug. However, drugs such as antibiotics, tranquilizers and hormones should be taken strictly under the supervision of a doctor, so as not to start an irreversible process and not harm your health.

Hello, Natasha! I think that you can learn about the effect of the drugs you listed on the conception and birth of a child from the annotation to them. Although, of course, even after reading this information, it is impossible to say exactly what the possible effect of these drugs on these things is. Because medications are not always studied for absolutely all factors, especially if the drugs are not taken during pregnancy and breastfeeding, and even more so if they are taken not by women, but by men.

This is exactly the conclusion I come to after reading the annotations. For example, the annotation for Keltikan describes only special instructions regarding pregnancy and lactation.

“The use of the drug during pregnancy and lactation is not contraindicated, but the appropriateness of taking the drug and the dose of the drug are determined by the doctor, depending on the advantage of the benefits of use over the potential risk to the fetus/child.”

From the annotation to Neuromedin:

“Pregnancy and lactation.

The use of the drug is contraindicated during pregnancy and lactation (breastfeeding).

Preparation does not provide teratogenic, embryotoxic action."

What do teratogenic and embryotoxic effects mean? Let's take a look at Wikipedia.

“Teratogenic effect (from the Greek τερατος “monster, freak, ugliness”) - a violation of embryonic development under the influence of teratogenic factors - some physical, chemical (including drugs) and biological agents (for example, viruses) with the occurrence of morphological abnormalities and defects development".

“The embryotoxic effect occurs in the first 3 weeks. after fertilization and consists in the negative effect of drugs on the zygote and blastocysts located in the lumen of the fallopian tubes or in the uterine cavity (before implantation) and feeding on uterine secretions.”

From these points of view, neuromedin is apparently safe.

It seems to me that it is better for you to consult a fertility specialist with these and other questions regarding the conception and birth of a healthy child. Experts know better about the possible side effects of medications. In addition, I think that first of all, it is worth paying attention not even to the medications that your husband is taking. And for the diseases for which he is trying to be treated with these medications. Since these medications are intended to treat neurological diseases, it is your husband’s congenital diseases that may become possible reasons for the birth of an unhealthy child. But these are just my guesses; it is better to receive more serious advice in person from specialists. Moreover, he can take the listed drugs only for a given period of time. And in other months he takes a number of other medications. I think it would also be a good idea to get some advice about them.

(based on the book by Dr. O.A. Mazur “Capillary therapy cures 95% of diseases”)

According to modern domestic and foreign medical statistics, a significant number of women have extragenital pathology at the time of pregnancy or suffer at various stages of pregnancy, that is, diseases of the extragenital area not directly related to the reproductive organs. According to the same data, up to 80% of women take at least one pharmacological drug during this period. On average, according to foreign experts, each pregnant woman takes 4 medications, not counting vitamins and iron supplements.

It is well known that many drugs cross the fetoplacental barrier and create real concentrations in the blood plasma of the developing fetus, which can adversely affect its development. Weakness in the function of the eliminating (removing toxins) organs of the unborn child can cause a fetotoxic (poisoning the fetus) effect when using even a medicine that is relatively harmless for an adult body. Incorrectly prescribed treatment can ruin a person’s entire future life.after his birth.

Doctors prescribing pharmacological drugs to pregnant women should know and take into account the following important points:

main periods of intrauterine development of the body;
embryotoxic (poisoning the embryo), teratogenic (causing deformities) and fetotoxic effects of drugs;
metabolism (transformation in the body) of medications in pregnant women;
passage of drugs through the placenta and amniotic fluid;
metabolic characteristics of the developing fetus;
the main periods of intrauterine development and the effects of drugs on the unborn child.

As is known, the human body in the initial period of its development goes through three stages:

Period of blasto- and embryogenesis;
Period of fruit development;
Newborn period.

Therefore, medications used by a pregnant woman can cause three types of effects on the body of the unborn child: embryotoxic, teratogenic and fetotoxic.

Embryotoxic effect

The embryotoxic effect occurs in the first three weeks after fertilization of the egg and consists in the negative effect of drugs on the zygote and blastocysts located in the lumen of the fallopian tubes or in the uterine cavity (before implantation of the fertilized egg into it) and feeding on uterine secretions. Damage and, as a rule, death of the blastocyst is caused by the following pharmacological substances: hormones (estrogens, progestogens, growth hormone, deoxycorticosterone acetate), antimetabolites (mercaptopurine, fluorouracil, cytarabine, etc.), inhibitors of carbohydrate (iodoacetate) and protein (actinomycin) metabolism, salicylates, barbiturates, sulfonamides, fluorine-containing substances, antimitotic agents (colchicine, etc.), nicotine. If the human embryo continues to develop in the mother's womb, it means that it is not damaged.

Teratogenic effect

A teratogenic effect can develop from the third to the tenth week of pregnancy (but many experts rightly suggest extending the boundaries of the dangerous period until the 12th week of pregnancy) and leads to various disturbances in the normal development of the fetus, the occurrence of anomalies of its internal organs and systems. The type of defect depends on the duration of pregnancy, on which organs are laid down and intensively formed in the embryo during the period of taking the drug. It is believed that the most dangerous period for the development of major defects, that is, for the manifestation of teratogenicity of the drug, is the 3-10th week of intrauterine development, which corresponds to approximately 5-12 weeks after the first day of the last menstruation. Consequently, teratogenic effects are most likely soon after implantation of the egg into the uterine wall, that is, when the woman often does not yet know that she is pregnant.

The likelihood of developing a defect in the fetus depends not only on the pharmacological drug prescribed to the pregnant woman, but also on her age (the likelihood increases if the pregnant woman is under 17 or over 35 years old), on her state of health, the functioning of the drug elimination (removal) organs, the dose of the drug, the duration of its appointment, genetic predisposition to the development of a particular defect.

According to the degree of danger of developing a teratogenic effect, researchers divide drugs into three groups.

Group 1 of substances that are extremely dangerous for the developing fetus and therefore absolutely contraindicated in pregnant women include: thalidomide, antifolate drugs (methotrexate, trimethoprim, co-trimoxazole), androgens, diethylstilbestrol and hormonal oral contraceptives. It is recommended to stop taking the latter at least 6 months before the planned pregnancy.

Group 2 includes medications that are somewhat less dangerous to the fetus and are prescribed to those suffering from epilepsy, diabetes, malignant neoplasms, and some others. Chronic diseases themselves are, of course, a factor predisposing to the occurrence of a teratogenic effect. However, the potential danger of the teratogenic effect of pharmacological drugs of this group, which includes: antiepileptic drugs (difenin, hexamidine, phenobarbital, valproic acid), alkylating antitumor drugs (embiquine, dopan, sarcolysine, chlorbutin), oral (orally administered) antidiabetic drugs, as well as ethanol (ethyl alcohol) and progesterone.

The 3rd group includes drugs that cause malformations under conditions predisposing to this: the first trimester of pregnancy, young or “old” age of the pregnant woman, high doses of the drug, etc. This group of drugs consists of: salicylates, antibiotics of the chloramphenicol and tetracycline, anti-tuberculosis drugs, quinine, imizin, fluorotane (dangerous for pregnant women - workers in anesthesiology departments), vitamin K antagonists, meprotan, neuroleptics, diuretics, anaprilin.

Fetotoxic effect

In the later stages of pregnancy, the fetal organs are mostly formed, so pharmacological agents can no longer cause large anatomical defects in it. Damage may include prematurity, tissue damage, inhibited or impaired organ function, or impaired behavioral responses. The administration of hormones, androgens or progestogens to a pregnant woman is accompanied by masculinization of the fetus. Iodide, lithium and antithyroid drugs used in large doses provoke the development of goiter. Tetracyclines interfere with the development of teeth and bones; quinolones interfere with cartilage development. Prostaglandin synthetase inhibitors (acetylsalicylic acid and indomethacin) can slow down the onset of labor and cause dysfunction of the cardiovascular system in the fetus, since prostaglandins are involved in maintaining the patency of the ductus arteriosus in the fetus, relaxing its muscles.

Fetotoxic effects occur due to an excessively pronounced and characteristic pharmacological effect on the fetus for a given drug (usually in the last weeks of pregnancy) or an undesirable effect specific to the drug. For example, administration of indomethacin to a pregnant woman results in closure of the ductus arteriosus in her fetus before labor occurs; beta-adrenergic agonists disrupt carbohydrate metabolism in the fetus; aminoglycoside antibiotics have an ototoxic effect on the fetus, that is, they affect the tissues and functions of the inner ear. Clinical experience shows that the administration of certain medications to pregnant women can lead to the development of perinatal (childbirth-related) pathology and even the death of the fetus or newborn child.

Medicines before childbirth

Medicines used on the eve of childbirth can cause negative pharmacological effects in the postnatal (postpartum) period. For example, difficulty breathing through the nose, drowsiness, and difficulty feeding a child occur when using reserpine. The antibiotic chloramphenicol causes vascular collapse and hematopoietic disorders in newborns, since it does not conjugate in them. Vasodilators provoke a decrease in blood supply to the uterus and fetus. When beta blockers are used, the fetus may not respond to hypoxia. Sulfonamide drugs displace bilirubin from its connection with plasma proteins, as a result of which the child is born with jaundice. Anticoagulants and antiplatelet agents increase the risk of bleeding. Children born to a woman addicted to opioid drugs may develop withdrawal syndrome with physical manifestations.

Children whose mothers took psychotropic drugs during pregnancy may experience mental changes due to a slowdown in the development of the central nervous system. In particular, such children may have difficulty learning in the future.

The lack of in-depth studies covering a large number of drugs does not allow clear recommendations for increasing or decreasing doses, so most pregnant women are administered drugs at normal therapeutic doses.

Medicines can enter the fetus through the placenta (transplacental route) and amniotic fluid (amniotic fluid), which it actively absorbs through its tracheobronchial tree and lungs, as well as through the gastrointestinal tract. For most pharmacological drugs, their accumulation in the amniotic fluid is low, but some create significant concentrations, for example the antibiotics ampicillin and oxacillin. This property is used in the treatment of intrauterine infections of the fetus.

Features of metabolism in the fetus

An important role in the processes of metabolism (biochemical transformation) of drugs is played by the function of the liver, which in the fetus is immature both functionally and morphologically. The functional maturation of the liver in the fetus and the appearance of drug-metabolizing enzymes in it occurs in parallel with histological (tissue) maturation until the moment of birth. However, full metabolism is possible only during postnatal development. Insufficient inactivation of drugs by the fetal liver leads to the fact that a number of drugs (barbiturates, narcotic analgesics, indirect anticoagulants and many others) have a more pronounced toxic effect on the fetus than on the maternal body.

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