During the period of bearing a child, a woman should be especially responsible for her own health. Now doctors recommend that each patient at certain times donate blood and undergo an ultrasound scan. The doctor compares the results with the norms of 2 screenings during pregnancy. After this, the patient may be prescribed treatment. How many weeks during pregnancy 2 screening is best done? In the article we will consider the answer to this question.
When screening is prescribed
During pregnancy, the expectant mother must be observed by a doctor. What is the recommended number of weeks for 2 screenings during pregnancy? A woman can donate blood for research from 15 to 20 weeks. It is believed that during this period you can most accurately determine the level of hormones in the body. But the most optimal time for screening will be from 16 to 18 weeks. During this period, it is possible to determine the biochemical composition of blood as accurately as possible. The information content of the study will be very high.
When is it best to do 2 screenings during pregnancy? Ideal dates for ultrasound from 19 to 24 weeks. If doctors have any concerns, then screening can be postponed to an earlier time. As a rule, first the doctor directs the expectant mother to donate blood, and after receiving the results of the study, she recommends an ultrasound scan. During this period, you can already clearly see the baby and understand how it develops in the womb.
With a favorable course of pregnancy, the doctor directs his patient for ultrasound in the period from 19 to 22 weeks. If during the study the abnormality is found in the fetus, then a woman may be assigned to re-scan. In some cases, the expectant mother may be assigned a consultation with a geneticist or other specialized specialists.
Why screening
This procedure is prescribed for every woman who carries a child, even if she has absolutely no complaints about her health. Deciphering 2 screenings during pregnancy is the responsibility of the doctor, who in the case of adverse test results, prescribes additional studies. Doctors pay special attention to women at one of the risk groups:
- Drinkers and drug users.
- Having a burdened gynecological history.
- Pregnant women for the first time over the age of 35.
- Having infectious diseases in the early stages.
Particular attention is paid to women who have been diagnosed with oncological pathology for a period of more than 14 weeks. Families in which future parents are in close consanguinity are at risk. What is 2 pregnancy screening for? In time to notice deviations from the norm in the development of the fetus and adjust them.
Also at risk are future mothers who have already had children with genetic abnormalities. Earlier screening may be given to those women whose previous pregnancies have ended in a miscarriage. At risk are future mothers, whose close relatives suffer from genetic pathologies. Doctors are required to especially carefully monitor the results of tests of the woman who had any problems during the first screening.
Study preparation
It is better to schedule a blood donation in the early morning so that a too long absence of breakfast does not cause dizziness. What does 2 screening during pregnancy show? According to its results, one can judge the development of the fetus and the health of the future mother. Some women experience so much screening that they cannot sleep. This must not be allowed. The main preparation that is needed before passing the tests is peace of mind. To this, the expectant mother should be taken in all seriousness, because she can not worry.
Donate blood strictly on an empty stomach. The last meal should be 6-8 hours before the study. If you eat shortly before blood donation, the results may not be entirely reliable, which will only add emotions to the expectant mother. The day before, it is not recommended to eat any foods that can cause allergies. It is also undesirable to eat fatty, sweet, flour. Before the test, it is advisable to drink some clean water.
Ultrasound can be done at any time. Despite the fact that the fullness of the intestines and bladder are not able to affect the results, it is advisable to empty them. This is due to the fact that during the study, a woman may want to use the toilet, she will not feel very comfortable.
Ultrasound in the second trimester
After examining the indicators of 2 screenings during pregnancy, the doctor issues a conclusion to the expectant mother. Despite the fact that everything is described in detail in it, for a person who does not understand medicine, these data will hardly be informative. Usually, an ultrasound doctor does not diagnose, but recommends that a woman visit her local gynecologist.
If you wait too long for a consultation, the patient may be interested in the results of perinatal screening. Do not forget that in the case when deviations are seen in only one indicator, the doctor will not judge the presence or absence of a pathology by it. All babies in the womb develop differently, so a woman should not worry about minor deviations from the norm. If the doctor notices that the child has a suspicion of pathology, he will immediately report it.
The doctor can determine the sex of the child with 2 screenings during pregnancy. But this can only be done if the baby is lying correctly. If the child covers his genitals or turns to a specialist booty, then it will not be possible to determine the sex during this ultrasound examination. In this case, parents can only come to terms with this fact and wait for the next screening, which is appointed in the 3rd trimester. But sometimes expectant mothers so want to know the baby’s sex that after a while they go on an ultrasound examination again.
Fetal parameters
Decoding 2 of the screening during pregnancy consists in analyzing the data obtained during the ultrasound examination. In the second trimester, the fetus is actively growing, so there will be a big difference between the indicators of 16 and 20 weeks. It should also be understood that all babies develop individually. If the doctor said that any parameter is normal, then so it is.
One of the most important indicators is the growth and body weight of the baby. If at the beginning of the 2nd trimester the fetus weighs only 100 g, then by the end this figure is already 300 g. The baby’s height also changes, at first it is 11.6 cm, and by the 20th week the baby grows to 16.4 cm in length. During ultrasound, the doctor must measure the circumference of the head and tummy. The first indicator at 16 weeks is from 112 to 136 mm. At the end of the trimester, the head circumference should be between 154 and 186 mm. The second indicator should have values from 88 to 164 mm.
Then the doctor finds out the fronto-occipital size. At the beginning of the trimester, it should be in the range from 41 to 49 mm, and at the end - from 59 to 68 mm. Another important parameter is biparietal size. Normally, it is from 31 to 53 mm (depending on the gestational age).
After the doctor measures the length of the leg bone. At the beginning of the trimester, this parameter should be from 15 to 21 mm, and at the end - from 26 to 34 mm. The length of the baby's femur is also measured. It should be from 17 to 37 mm (depending on the week of the study). What does 2 screening during pregnancy show? It gives an idea of how the baby develops.
The doctor must measure the humerus of the fetus, normally it should be from 15 to 34 mm. This value is directly related to the gestational age. The older the baby, the greater this figure. Then the doctor draws attention to the length of the bones of the forearm, this indicator should be in the range from 12 to 29 mm. Also, the doctor finds out the approximate amount of amniotic fluid. After that, he writes a conclusion.
Internal organs of the fetus
By the time of the planned ultrasound examination, the baby is already quite formed. Deciphering 2 screenings during pregnancy includes an assessment of the work of its internal organs. Particular attention is paid to the heart. The doctor assesses the rhythm and frequency of his contractions. In the second trimester, the heart occupies about a third of the fetal chest. The frequency of his strokes normally ranges from 140 to 160 per minute. The doctor draws attention to the size of the heart, its location and the shape of the interventricular septum. The structure of the tissues of the myocardium, endocardium, pericardium is also evaluated.
By the time of screening, the baby’s respiratory system is already fully formed. Ultrasound development of the lungs is assessed by the ratio of their echogenicity to the same indicator of the liver. The doctor determines the degree of maturity of the organ and its location. Normally, the lungs occupy about a third of the chest cross-section.
By the end of the 2nd trimester, kidney formation ends, which began another 3 weeks after conception. Depending on the duration of pregnancy, their size can be from 16 to 34 mm. The fetus already has a digestive system. The doctor must examine the entire gastrointestinal tract. Also, by the 20th week of pregnancy, the formation of the adrenal glands ends. Normally, their size at this period is from 9-10 mm.
Blood biochemistry
How is 2 screening during pregnancy? The doctor prescribes a woman to donate blood and undergo an ultrasound scan. Also at the reception, the gynecologist talks about the time when you need to re-approach the appointment. The doctor, focusing on the results of analyzes and expert opinions, prescribes treatment if necessary.
Usually, a specialist prescribes three types of blood tests, after which the level in the body of hCG, estriol, a-fetoprotein will be known. Sometimes a future mother is recommended to undergo another test, which will show the content of inhibin A.
During the second trimester, the level of human chorionic gonadotropin is from 10 to 35 thousand units. At the 16th week, blood should contain from 4.9 to 22.75 nmol / l of estriol, and at the 20th week it should already be from 7.35 to 45.5 nanomoles per liter. The level of alpha-fetoprotein by the end of the trimester should not exceed 57 units.
The probability of abnormalities in the fetus will be calculated by the doctor according to the multiplicity of the result of the marker to the average value. The optimal result will be 1. 1. The upper limit of this indicator will be 2.5, and the lower - 0.5. Normally, the risk of fetal abnormalities should not be less than 1 in 380.
False indicators
Expectant mothers often look forward to deciphering 2 screenings during pregnancy, but there may be errors in the conclusion. Naturally, this rarely happens in the modern world, but there are precedents. Decryption results can be affected by several factors that lead to errors.
For example, false indicators may appear in custody with multiple pregnancies. Sometimes the cause of the error lies in the incorrectly established period of conception, since the baby may be slightly younger or slightly older than doctors believe. The exact gestational age is generally very difficult to determine, of course, if a woman has not become pregnant after IVF.
False indicators are also possible if the expectant mother is obese or diabetes. Women at the age of 35 and older are at risk for incorrect interpretation of the results. Another reason for screening errors is the unhealthy habits of the expectant mother: addiction, substance abuse, smoking, alcoholism. Wrong results can be obtained by women taking hormonal drugs or undergoing in vitro fertilization.
Possible deviations
What is determined on 2 screening during pregnancy? The doctor looks at how the baby develops. Sometimes, according to the results of the tests, some pathologies can be suspected in the fetus. For example, with low estriol, specialists suggest intrauterine infection of the embryo. On the same basis, adrenal hypoplasia, anencephaly, and fetoplacental insufficiency can be suspected. In some cases, this indicator also suggests Down syndrome in the baby. With low estriol, there is a high risk of premature birth. If the rate is increased, then this can speak of both multiple pregnancy and liver disease in the expectant mother.
Low levels of alpha-fetoprotein are often a symptom of Edwards syndrome. In some cases, a similar analysis result indicates fetal death. Also, a low indicator of this substance can be a symptom of Down syndrome. High levels of alpha-fetoprotein indicate the following diseases: Meckel syndrome, umbilical hernia, malformation of the nervous system, and death of liver cells.
Low hCG values in some cases indicate the development of Edwards syndrome in the fetus. A high level of human chorionic gonadotropin indicates the presence of Down syndrome or Klinefelter in the baby. However, sometimes such a symptom only indicates that pregnancy has occurred as a result of IVF.
Next steps
Reviews of 2 screenings during pregnancy are mostly positive, since often it shows that the baby is healthy. Women understand that research is necessary, therefore they comply with the doctors' orders meekly. In the reviews, they write that it is quite simple to take tests. The slight discomfort associated with visiting the clinic does not scare anyone, because it is most important to know that the pregnancy is developing normally.
But what if the decryption results did not please? In this case, do not give up. Sometimes after a few weeks it is enough to do a second ultrasound examination to make sure that everything is fine with the child.
The doctor may also recommend amniocentesis. In this procedure, a doctor takes a small amount of amniotic fluid through a puncture in the peritoneum. Usually, the result of the analysis shows that the baby is healthy. The disadvantage of this study is that sometimes it can provoke a miscarriage.