Determination of gestational age using ultrasound genetic screening at 11-14 weeks

Today, in the era of high development of information technology and, thereby, active popularization of knowledge about various diseases of the population, incl. During pregnancy, improving family planning methods, it is relevant to increase the knowledge of women planning pregnancy about the risk of developing gestational diabetes mellitus in order to timely seek medical help in highly qualified medical institutions, where this problem is dealt with by doctors with extensive clinical experience in managing such patients.

basic information

Gestational diabetes mellitus, which develops during pregnancy, is characterized by hyperglycemia (increased blood glucose levels). In some cases, this disorder of carbohydrate metabolism may precede pregnancy and be first identified (diagnosed) only during the development of this pregnancy.

During pregnancy, physiological (natural) metabolic changes occur in the mother's body, aimed at the normal development of the fetus - in particular, the constant supply of nutrients through the placenta.

The main source of energy for the development of the fetus and the functioning of the cells of its body is glucose, which freely (through facilitated diffusion) penetrates the placenta; the fetus cannot synthesize it on its own. The role of the conductor of glucose into the cell is played by the hormone “insulin”, which is produced in the β-cells of the pancreas. Insulin also promotes the “storage” of glucose in the fetal liver.

Amino acids - the main building material for protein synthesis in the fetus, necessary for cell growth and division - are supplied in an energy-dependent way, i.e. through active transfer across the placenta.

In the mother’s body, to maintain energy balance, a protective mechanism is formed (“rapid starvation phenomenon”), which implies an immediate restructuring of metabolism - preferential breakdown (lipolysis) of adipose tissue, instead of the breakdown of carbohydrates with the slightest restriction in the supply of glucose to the fetus - ketone bodies (products) increase in the blood fat metabolism are toxic to the fetus), which also easily penetrate the placenta.

From the first days of physiological pregnancy, all women experience a decrease in fasting blood glucose levels due to accelerated excretion in the urine, decreased glucose synthesis in the liver, and glucose consumption by the fetoplacental complex.

Normally, during pregnancy, fasting blood glucose does not exceed 3.3-5.1 mmol/l. The blood glucose level 1 hour after eating in pregnant women is higher than in non-pregnant women, but does not exceed 6.6 mmol/l, which is associated with a decrease in motor activity of the gastrointestinal tract and an increase in the absorption time of carbohydrates supplied with food.

In general, in healthy pregnant women, fluctuations in blood glucose occur within very narrow limits: on an empty stomach on average 4.1 ± 0.6 mmol/l, after meals - 6.1 ± 0.7 mmol/l.

In the second half of pregnancy (starting from the 16-20th week), the fetal need for nutrients remains highly relevant against the backdrop of even faster growth rates. The placenta plays a leading role in changes in a woman’s metabolism during this period of pregnancy. As the placenta matures, active synthesis of hormones of the fetoplacental complex occurs, which maintain pregnancy (primarily placental lactogen, progesterone).

As the duration of pregnancy increases, for its normal development in the mother's body, the production of hormones such as estrogens, progesterone, prolactin, cortisol increases - they reduce the sensitivity of cells to insulin. All these factors, against the background of decreased physical activity of the pregnant woman, weight gain, decreased thermogenesis, decreased insulin excretion by the kidneys, lead to the development of physiological insulin resistance (poor tissue sensitivity to its own (endogenous) insulin) - a biological adaptive mechanism for creating energy reserves in the form of adipose tissue in in the mother's body in order to provide nutrition to the fetus in case of starvation.

In a healthy woman, a compensatory increase in insulin secretion by the pancreas occurs approximately three times (the mass of beta cells increases by 10-15%) to overcome such physiological insulin resistance and maintain blood glucose levels normal for pregnancy. Thus, there will be an increased level of insulin in the blood of any pregnant woman, which is the absolute norm during pregnancy!

However, if the pregnant woman has a hereditary predisposition to diabetes mellitus, obesity (BMI more than 30 kg/m2), etc. The existing secretion of insulin does not allow overcoming the physiological insulin resistance that develops in the second half of pregnancy - glucose cannot penetrate the cells, which leads to an increase in blood sugar and the development of gestational diabetes mellitus. Through the bloodstream, glucose is immediately and unhinderedly transferred through the placenta to the fetus, facilitating its production of its own insulin. Fetal insulin, having a “growth-like” effect, leads to stimulation of the growth of its internal organs against the background of a slowdown in their functional development, and the entire flow of glucose coming from the mother to the fetus through its insulin is deposited in the subcutaneous depot in the form of fat.

As a result, chronic hyperglycemia of the mother harms the development of the fetus and leads to the formation of so-called diabetic fetopathy - fetal diseases that occur from the 12th week of intrauterine life until the onset of labor: high fetal weight; violation of body proportions - large belly, wide shoulder girdle and small limbs; advance of intrauterine development - with ultrasound, an increase in the main dimensions of the fetus in comparison with gestational age; swelling of the tissues and subcutaneous fat of the fetus; chronic fetal hypoxia (impaired blood flow in the placenta as a result of prolonged uncompensated hyperglycemia in a pregnant woman); delayed formation of lung tissue; trauma during childbirth.

Why is it necessary to know the gestational age during IVF?

Determining the exact timing of pregnancy plays a critical role in maintaining the health of mother and baby and, ultimately, in a successful delivery. It is necessary for the following purposes:

• Determining the date of delivery . Childbirth is a complex process that poses a certain threat to the health and life of the woman herself and her child. Therefore, preparation for them must begin in advance, and for this you need to know the estimated start date. This is especially true for patients who have undergone IVF, since in their case pregnancy is more difficult, because it is, in fact, the result of medical treatment for infertility. Accordingly, in the case of in vitro fertilization, the risk of miscarriage, frozen embryo development and other complications increases.
• Carrying out an abortion procedure. Unfortunately, not every pregnancy ends successfully. During the process of bearing a child, especially after IVF, a woman may experience serious complications that threaten her health and life. Often, to preserve them, doctors resort to artificial termination of pregnancy as the only possible option. However, abortion (especially surgical) in itself is a serious stress for the mother's body and can only be carried out in the early stages of pregnancy. If the exact timing of gestation is unknown, the doctor is not able to accurately determine at what stage of development the fetus is, and may carry out the procedure late, which is fraught for the woman, at best, with the final loss of the opportunity to have children in the future, and at worst, with her death.
• For pregnancy management. Women who have undergone in vitro fertilization require more careful medical supervision. Pregnancies resulting from IVF are at increased risk of complications. Accordingly, the doctor must know its exact timing in order to choose the appropriate medical care strategy, including the prescription of certain medications and their dosages, diagnostic and therapeutic measures.

Calculating the period of conception after IVF is also necessary to monitor the development of the fetus, identify possible congenital anomalies, correct the mother’s lifestyle, her diet and other goals. Timely and accurately calculated medical care is the main factor ensuring the normal course of pregnancy after IVF and successful delivery.

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Child health problems with gestational diabetes mellitus

Thus, at the birth of children with fetopathy, there is a violation of their adaptation to extrauterine life, which is manifested by the immaturity of the newborn even with a full-term pregnancy and its large size: macrosomia (child weight more than 4000 g), respiratory disorders up to asphyxia (suffocation), organomegaly (enlarged spleen, liver, heart, pancreas), heart pathology (primary damage to the heart muscle), obesity, jaundice, disorders in the blood coagulation system, the content of erythrocytes (red blood cells) in the blood increases, as well as metabolic disorders (low values ​​of glucose, calcium , potassium, magnesium blood).
Children born to mothers with uncompensated gestational diabetes mellitus are more likely to experience neurological diseases (cerebral palsy, epilepsy); during puberty and thereafter, the risk of developing obesity, metabolic disorders (in particular, carbohydrate metabolism), and cardiovascular diseases is increased.

On the part of a pregnant woman with gestational diabetes mellitus, polyhydramnios, early toxicosis, urinary tract infections, and late toxicosis are more common (a pathological condition that is manifested by the appearance of edema, high blood pressure and proteinuria (protein in the urine), develops in the second and third trimester up to preeclampsia - cerebrovascular accident, which can lead to cerebral edema, increased intracranial pressure, functional disorders of the nervous system), premature birth, spontaneous abortion, delivery by cesarean section, labor anomalies, and trauma during childbirth are more common.

Disorders of carbohydrate metabolism can develop in any pregnant woman, taking into account the hormonal and metabolic changes that consistently occur at different stages of pregnancy. But the highest risk of developing gestational diabetes is in women who are overweight/obese and over 25 years of age; presence of diabetes in close relatives; with disorders of carbohydrate metabolism identified before the current pregnancy (impaired glucose tolerance, impaired fasting glycemia, gestational diabetes in previous pregnancies); glucosuria during pregnancy (the appearance of glucose in the urine).

Gestational diabetes mellitus, which first developed during pregnancy, often does not have clinical manifestations associated with hyperglycemia (dry mouth, thirst, increased volume of urine excreted per day, itching, etc.) and requires active detection (screening) during pregnancy !

What causes anembryonic pregnancy?

• Genetic disorders when combining the chromosomes of the parents; an unsuccessful combination of the genes of a woman’s egg and a man’s sperm is also possible. • Bacterial and viral infections in parents. • Negative effects of toxic substances or radiation. • Hormonal imbalances in a woman’s body. • Abuse of cigarettes, alcohol, drugs.

The mechanism of anembryonia has not yet been thoroughly studied by medicine, so it can happen even in a healthy woman. Cytogenetic and histological examination of material extracted from the uterine cavity and examination of both spouses for infections will help determine the cause of anembryonia. If a cytogenetic study has not been carried out or the result of the study indicates the presence of genetic or chromosomal abnormalities of the elements of the fetal egg, it is necessary to conduct a study of the karyotype of the spouses and visit a geneticist. To exclude male factor, in some cases it is necessary to take a spermogram.

Necessary tests

All pregnant women must have their fasting venous blood plasma glucose tested in a laboratory (cannot be tested using portable glucose self-monitoring devices - glucometers!) - against the background of a normal diet and physical activity - upon first contact with the antenatal clinic or perinatal center (as possible earlier!), but no later than 24 weeks of pregnancy. It should be remembered that during pregnancy the blood glucose level on an empty stomach is lower, and after eating it is higher than outside pregnancy!

Pregnant women whose blood glucose levels, according to WHO recommendations, meet the diagnostic criteria for diabetes mellitus or impaired glucose tolerance are diagnosed with gestational diabetes mellitus. If the results of the study correspond to normal indicators during pregnancy, then an oral glucose tolerance test - OGTT ("stress test" with 75 g of glucose) is mandatory at 24-28 weeks of pregnancy in order to actively identify possible disorders of carbohydrate metabolism. All over the world, OGTT with 75 g of glucose is a safe and the only diagnostic test for detecting disorders of carbohydrate metabolism during pregnancy!

Remember that normalizing carbohydrate metabolism in a pregnant woman allows you to avoid complications from both the course of pregnancy itself and the condition of the fetus!

After a diagnosis of gestational diabetes mellitus is made, all women require constant monitoring by an endocrinologist together with an obstetrician-gynecologist. Pregnant women should be trained in the principles of rational nutrition, self-control and behavior in conditions of a new pathological condition (i.e., timely testing and visits to specialists - at least once every 2 weeks).

A pregnant woman's diet should be sufficiently high in calories and balanced in basic food ingredients to provide the developing fetus with all the necessary nutrients. At the same time, in women with gestational diabetes mellitus, taking into account the characteristics of the pathological condition, nutrition should be adjusted. The basic principles of diet therapy include ensuring stable normoglycemia (maintaining blood glucose levels corresponding to those for physiological pregnancy), and preventing ketonemia (the appearance of fat breakdown products - “hungry” ketones - in the urine), as mentioned above in the text.

Increased postprandial blood glucose levels (above 6.7 mmol/L) are associated with an increased incidence of fetal macrosomia. Therefore, a pregnant woman should exclude easily digestible carbohydrates from food (which lead to a rapid uncontrollable rise in blood glucose) and give preference in the diet to difficult-to-digest carbohydrates high in dietary fiber - carbohydrates protected by dietary fiber (for example, many vegetables, legumes) have a low glycemic index. The glycemic index (GI) is a factor in the rate of absorption of carbohydrates.

What is an anembryonic pregnancy?

The second name for this type of non-developing pregnancy is “empty ovum syndrome,” and it immediately becomes clear what we are talking about. Anembryonic pregnancy is a condition in which there is a pregnancy, but no embryo. This situation occurs when fertilization has occurred and the membranes have begun to form, but there is no embryo in it.

At the same time, external signs of pregnancy remain - menstruation does not occur, the breasts become full, fatigue increases, and the level of hCG in the body increases and the corpus luteum develops, but... there is emptiness inside the fertilized egg. The embryo either did not form, or for some reason stopped developing in the initial stages of its formation.

For a more accurate diagnosis, in some cases, when establishing the gestational age, it is necessary to perform a dynamic ultrasound (2 or more), since the embryo may simply be small in size, and with a dynamic study, the size of the fetal egg and embryo should increase.

What are the symptoms of anembryonic pregnancy?

There are no specific symptoms of anembryonic pregnancy. However, with anembryonia, more often than with a normally developing pregnancy, symptoms of threatened miscarriage occur in the form of bloody discharge and pain in the lower abdomen. When testing blood for hCG, this indicator may not correspond to the expected gestational age. And only by ultrasound can you see the absence of an embryo. With anembryonia, pregnancy cannot develop indefinitely and always ends in spontaneous miscarriage in the 1st trimester (up to 12 weeks).