How many weeks is 3 screening? Routine examination of pregnant women

The screening test is conducted once in each trimester. In how many weeks 3 screening is necessary, the doctor will explain in detail. The main thing is to have an ultrasound examination in the period from the 32nd to the 36th week. At the last ultrasound, the condition and position of the fetus is finally determined (by this time the fetus should occupy a longitudinal position with the head presentation).

Which examinations include screening for the 3rd trimester

The last screening consists of several procedures. For all pregnant women, only an ultrasound is mandatory, the remaining procedures and examinations are performed as prescribed by the doctor. The complex of possible diagnostics includes:

• Dopplerography - 3 screening during pregnancy focuses on the correct location of the fetus and the stage of maturation of the placenta (during this period, it should be in the 2nd stage of maturation).
• CTG - cardiotocography (examination of the heart rate of the fetus).
• Biochemical blood test (triple - with determination of total hCG, RAPP-A and ɑ-fetoprotein).

Biochemical analysis is prescribed only for certain indications. In the last trimester, unlike the first, it is necessary to conduct a triple test instead of a double test, in order to more fully evaluate the development of the fetus.

What is ultrasound used for in the third trimester?

In how many weeks, 3 screening needs to be done, each doctor determines individually. It depends on many indicators. At the last ultrasound study, great attention is paid to the following characteristics:

• The state of the cardiovascular system, the presence of heart disease or other pathologies localized in this area.
• Since in the last weeks the brain is rapidly growing and developing, ultrasound is given special attention to the study of this organ (in particular, the brain and oblong brain).
• The Venus Galena, which is located in the cavity of the skull, is carefully studied and has an important function for the normal functioning of the adjacent organs.
• The state of the face is assessed - features of the nasolabial triangle, upper lip and orbitals. Terms of the 3 screening allow you to accurately determine the correctness of the development of the facial area of the fetus and exclude any pathology.
• Important is the proper development and condition of the spine, abdominal organs, urogenital system.
• The condition of the amniotic fluid, umbilical cord and placenta (its thickness, localization and degree of maturity) is diagnosed.
• Also, the genital organs of the mother are examined: the uterus and appendages.

In addition to these indicators, the doctor evaluates the features of the location of the fetus in the uterus, the presence of an umbilical cord and the presentation of the fetus. If the neck is wound with the umbilical cord, an additional ultrasound may be required in a week or two to see if the position of the fetus has changed and whether the whiplash has been eliminated. In some cases, caesarean section may be required.

Carrying out Doppler

Dopplerometry is a study of the characteristics of blood flow in the umbilical cord, vessels of the uterus and fetus. It is necessary to determine the characteristics of the blood flow, allows you to detect a lack of oxygen, the presence of pathologies of the central nervous system or the cardiovascular system.

In how many weeks, 3 ultrasound screening and doppler can be done? As a rule, in the presence of a suitable apparatus, which makes it possible to diagnose the features of the blood flow, these studies are carried out simultaneously. Therefore, if it is necessary to conduct dopplerometry, the gynecologist will send to the laboratory where it is possible to conduct two examinations at once. In addition, this approach will significantly save money.

Conducting cardiotocography

CTG is performed to determine the possible hypoxia of the fetus. It allows to determine the number of heartbeats of a child in a state of rest and with motor activity. How is this type of screening done? Carrying out the examination like ultrasound, the only difference is that with CTG, the fetus and its blood flow are not visualized, and only the features of the heartbeat are projected on the screen - slowing or increasing (depending on the tests).

At 3 screening, it is possible to determine the degree of maturity of the lung tissue and the child's readiness for birth. If a bad result is found, it may be necessary to hospitalize a pregnant woman and, in some cases, preterm delivery in order to preserve the life and health of the mother and child.

How screening is done: the features of CTG

If the features of the ultrasound is clear, then the technique of cardiotocography causes many questions in pregnant women. The examination consists in using an ultrasonic sensor, it can be convex or flat. The sensor is fixed on the abdomen of the pregnant woman with a soft strap in the place where the heartbeat of the fetus is best listened.

A woman at this time is given a special console, which she will need to press at the moment the fetus moves. The procedure takes an average of 40 minutes. If necessary, the doctor can recommend the movement of the fetus, irritating the abdominal wall or eating a piece of chocolate.

If you can not cause the fetus to move in such ways, the doctor can resort to the introduction of special medicines into the vein, with the help of which the preparation will be displayed if the fetus has hypoxia.

Blood chemistry

In addition to these examinations, a biochemical blood test is also required, which includes 3 screenings. What is looked at in this analysis? In addition to the standard indices of total hCG and RAPP-A, an examination of the parameters of free estriol and placental lactogen is mandatory .

All indicators should normally be in the range of 0.5-2 MW. If the measurements take place in other units, then the standards in the other column will be indicated in the laboratory. Since each laboratory has its own characteristics of calculating the normal parameters of pregnancy hormones in the blood.

These indicators indicate normal fetal development if their concentration is within the normal range. Most often, blood biochemistry is prescribed only if there are bad tests that were made in the second trimester of pregnancy.

Dates of the 3rd screening

"When do 3 screenings?" - a question that only the attending physician can answer. The final terms of the survey depend on the individual characteristics and indicators of the pregnant woman.

Most often, ultrasound is performed at 32-34-th week, after which the results should be sent to the biochemistry of the blood. Conduct CTG and dopplerography can begin as early as the 28th week, especially if there is a special doctor's testimony for this.

Timely examination allows excluding the possibility of hypoxia of the fetus and other dangerous changes in its development.

Which training includes 3 screenings

What doctors watch, greatly affects the features of preparing a pregnant woman. Thus, the conduct of ultrasound, CTG and Dopplerometry does not require preliminary preparation. While a blood test requires compliance with a certain diet. The list of prohibited products includes:

• Fatty and fried foods;
• Sharp and salty dishes;
• Smoked products;
• chocolate.

Also it is worth recalling that just before the test is done, you must endure a 4-hour break in eating. Compliance with the diet is necessary to maintain the normal state of blood plasma, because when fatty foods are used, fatty drops are deposited in it, which distort the results, and in some cases make it impossible to carry out the diagnosis.

The norms of the third screening

The interpretation of the 3 screening requires attentiveness on the part of the doctors. In the third trimester, there are certain indicators and their norms. The main ones are:

• The thickness of the placenta. Normally, for a period of 32-34 weeks, the thickness varies between 25-43 mm.
• The degree of maturity of the placenta. At the 32nd week the placenta is at the 1st or 2nd degree of maturation.
• The index of amniotic waters. It varies within the range of 80-280 mm.
• The internal cervical cervix should be closed, and its length should be at least 3 cm.
• The tone of the uterus should not be normal. Otherwise, there is a possibility of the onset of premature birth or placental abruption.
• Fetal weight is within 2 kg, and height is 45 cm, abnormalities and pathologies of development are normal.

Correctly to decipher results of inspection the doctor who initially conducts pregnancy and knows all nuances of its current can only. "How many weeks does the optimal screening take?" Is a question that depends on a variety of individual factors.