When is the second screening done? Terms, norms, decoding

2024 Author: Priscilla Miln | [email protected]. Last modified: 2023-12-16 00:21

Expectant mother, bearing a baby, always hopes for a successful pregnancy. But her expectations are not always met. Currently, the pathological development of the fetus is very common. For example, such serious developmental abnormalities as Down syndrome, Turner syndrome, Noonan syndrome and many other chromosomal pathologies can be detected in early pregnancy.

The main method for detecting deviations in the development of the baby is the implementation of the first and second screening. Many experts say that the second one is more informative.

Let's take a closer look at what this procedure is, and dwell on the very concept of the second screening during pregnancy, what week it is advisable to take it and whether there is any point in this manipulation.

Screening: the essence of screening pregnant women

Purposefulexamination of the female body during pregnancy in medical practice is called screening. If, as noted, this is a purposeful procedure, then it should be told what exactly is being investigated and why.

Screening is done two or three times throughout pregnancy. The first (during the first trimester of pregnancy - 8-10 weeks) involves a complete medical examination:

• weighing;
• blood pressure measurement;
• testing: blood, urine;
• determination of blood type and Rh factor;
• testing for HIV infection and other infectious diseases (hepatitis, STDs, tuberculosis);
• intrauterine ultrasound;
• gathering information about hereditary, genetic diseases.

Based on a woman's he alth status, experts often recommend a second screening for a mother-to-be. This refers to the examination during the second trimester of pregnancy (15-20 weeks). Important indicators at this stage are:

• ultrasound results;
• venous blood tests;
• hormonal panel.

The third screening is done during the third trimester of pregnancy (30-35 weeks). At this stage, the results of ultrasound and Doppler sonography are important.

Screening gives the specialist observing the course of the patient's pregnancy a complete picture of the development of the fetus and changes in the he alth of the expectant mother. Identifies the risks of possible deviations or their presence.

What you needknow

Screening is not a therapeutic procedure, the examination only allows you to observe the development of the fetus after conception. Pregnancy does not always proceed normally. There are cases when experts recommend termination of pregnancy at a certain time due to the identification of serious abnormalities in the development of the fetus. But there are many such situations when it is possible to carry a baby, even with detected physical and genetic problems. The decision to give birth always remains with the future parents.

It should be understood that:

• neither parents nor doctors can influence the development of pathologies - in many cases the process is irreversible;
• children born with chromosomal diseases are deprived of a full life and require constant monitoring;
• despite the availability of modern research methods, it is not always possible to make the correct diagnosis, therefore, in some controversial situations, pregnancy is monitored for three trimesters.

Where are pregnant women screened?

Examination of pregnant women is carried out in the antenatal clinic at the place of residence, where the expectant mother applies for registration. The leading specialist assigns a certain list of examinations to the patient and writes out a referral to medical centers or medical rooms. There, she can take tests and get the results, with which she subsequently comes to visit her doctor.

After examining the results, the doctor makes a decision:

• following up the patient;
• monitoring her condition and the development of the fetus;
• maintain or terminate the pregnancy.

Mandatory Screening Schedule

There is no exact schedule for screening. For each pregnant woman, the period is individual. Therefore, when looking for an answer to the question of how many weeks the second screening is done, you can only get information that the procedures are feasible during the second trimester.

This period allows you to evaluate not only the results of biochemical parameters, but also the anatomical structure of the fetus.

At what week of pregnancy is the second screening done?

The second stage of examinations is appointed after the first. Many women have certain indications for a second screening. In how many weeks it is better to do this procedure, the observing doctor himself suggests. We emphasize that in most cases there are grounds for passing the second screening.

The clarity of the results of the examination depends on the week in which the second screening is carried out during pregnancy. Approximate terms - at 15-20 weeks. Results obtained at 15 weeks, for example, will differ from responses obtained at 20. Fetal development depends on many social and hereditary factors, so recommendations for screening timing are averaged.

Detailed description of the steps of the second screening

No matter how many weeks the second screening isthe basis is taken a period of 15-20 weeks, the list of prescribed procedures is as follows:

• biochemical blood test - blood is taken from a vein and examined for the content of hormones and protein;
• non-invasive blood test - isolating fetal DNA and examining it for chromosomal abnormalities;
• ultrasound examination of the anatomy of the fetus, the amount of amniotic fluid, the state of the placenta.

If there are any abnormalities identified as a result of the above procedures, a pregnant woman is recommended to undergo:

• cordocentesis - cord blood sampling;
• amniocentesis - amniotic fluid sampling.

These two procedures carry a high risk of miscarriage, miscarriage and preterm labor. Therefore, they are prescribed only in exceptional cases, they are performed only with the consent of the future woman in labor. This is also emphasized by the reviews that answer the question, at how many weeks the second screening during pregnancy is done.

What abnormalities can screening at the second term of pregnancy show?

Specialists, when conducting a second screening during pregnancy, can identify pathologies and anomalies in the development of the fetus, such as:

• Down syndrome;
• Patau syndrome;
• Edwards syndrome;
• cystic fibrosis;
• galactosemia;
• hypothyroidism;
• non-molar triplodia;
• phenylketonuria;
• galactosemia;
• anatomical pathologies and other abnormalitiesfrom the norm.

Can I opt out of screening?

Of course, parents are responsible for the he alth of the unborn baby. Fetal monitoring is recommended for all women, regardless of he alth conditions. The second screening is very important during pregnancy! When they conduct an examination in the second trimester, specialists can detect many deviations that could not be determined in the first terms.

Every woman in labor has the right to refuse additional examinations. But we must not forget that in this case, the risks of the birth of an inferiorly developed child and the deterioration of the he alth of the expectant mother increase.

Rejection of research is appropriate only if the he alth indicators of the future woman in labor are normal. In this situation, only ultrasound is recommended for women without additional manipulations.

What are the indications for screening?

These are the following criteria:

• the age of the woman in labor has exceeded 30 years;
• test results during the first trimester have a number of deviations from the norm;
• first screening showed pathological changes;
• the first child in the family has a genetic disease;
• the presence of chronic or hereditary diseases in a future woman in labor, requiring the use of drugs that are undesirable during pregnancy;
• pre-pregnancy miscarriages, fetal fading;
• prior abortions;
• woman diagnosed with sexually transmitted diseases;
• the expectant mother is a carrier of HIV infection;
• relations between spouses;
• radiation exposure of one of the spouses before conception;
• infectious diseases transmitted by airborne droplets, transferred during the first stages of pregnancy, including influenza.

Screening results

If you are interested in how many weeks screening is done, then you should also know what the results of examinations of a pregnant woman mean. Attention should be focused on quantitative indicators.

The decoding of a biochemical blood test is as follows:

• ACE (fetal protein) - the norm is 15-95 units / ml, underestimated indicators determine the presence of chromosomal abnormalities, overestimated - underdevelopment of the neural tube, spinal cord.
• Estriol (hormone) - the norm is 9.9-18.9 nmol / l, overestimation indicates problems with the functioning of the internal organs of the pregnant woman, understatement - chromosomal abnormalities of the fetus.
• hCG (hormone) - the norm is 4720-80100 IU / l, overestimation indicates chromosomal abnormalities in the development of the fetus, underestimation can mean developmental delays, threats of miscarriage, miscarriage.

Ultrasound results, no matter how many weeks the second screening is done, can show the following picture:

• maturity of the placenta;
• the condition of a woman's reproductive organs;
• fetal position;
• place and condition of the umbilical cord;
• IAH - oligohydramnios can be fraught withunderdevelopment of the fetal skeleton and nervous system;
• the state of the internal organs of the fetus, the presence of limbs, the gender of the unborn baby.

Cordocentesis allows you to make an approximately accurate diagnosis of chromosomal abnormalities and hereditary diseases transmitted from parents to the fetus. The karyotype determined in this way allows you to make a choice between maintaining the pregnancy or terminating it.

When can screening be false?

Taking into account all of the above, it should be concluded that no matter how many weeks the second screening and ultrasound are done during pregnancy in particular, the results of the procedures cannot be 100% accurate.

Deceptive indicators can be:

• if the future woman in labor has chronic diseases;
• when a woman is underweight or overweight;
• if you do not follow a full meal schedule;
• with high nervous tension;
• when carrying multiple children;
• if the fetus is too large;
• when conceived through IVF.

How to avoid inaccurate indicators?

It is possible to bring survey indicators closer to more accurate and truthful if the following recommendations are followed:

• quitting smoking;
• following a diet for a day and fasting six hours before donating blood from a vein;
• restriction of taking medications a week before testing.

Preparation for cordocentesis involves additional archresearch.

Now you know how many weeks the second screening is done and for what purpose. The list of examinations for each woman in labor is individual. Their timely passage reduces the risks of bearing an inferiorly developed child. Remember this!