About screening for diseases during pregnancy
For all diseases, whether pregnant or non-pregnant, the first strategies recommended by doctors are: early prediction, early detection, early prevention and early intervention. This is a common practice in health management, health promotion, disease prevention and disease control.
This unisex practice in Xian Yi, old and young, is best implemented in obstetrics, which is universal.Pregnancy check-up mode.
The mode of prenatal check-up during pregnancy originated in Britain. As early as 1929, the British Ministry of Health issued a memorandum recommending pregnant women to have regular prenatal check-ups. This systematic management mode of prenatal check-up was quickly accepted and popularized all over the world.
In the last century, this measure made a great contribution to the remarkable reduction of maternal mortality and perinatal mortality rate all over the world.
The main purpose of prenatal examination is screening for diseases during pregnancy.For those relatively common diseases that may have adverse effects on mothers and fetuses, screening is conducted in order to find risks, make early prediction, early prevention and intervention.
Screening for diseases during pregnancy is aimed at normal people.It is all pregnant women, not a few, who want to screen out people with problems in the normal population.
So don’t always question why everything is normal when you are pregnant. The doctor still has to prescribe all kinds of laboratory tests for you. You should be happy to find out that there is no problem. Don’t think it’s a waste of money. Do you want every penny to be spent, and every laboratory test can find out the problem?
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If it is a high-risk population, screening is generally not needed, and diagnostic examination can be carried out directly.
Compared with screening, diagnostic examination methods are usually more complicated, more expensive and more likely to be invasive.
As for which diseases need screening, which diseases don’t need screening and which screening method to use, it needs comprehensive consideration.
Screening needs to balance screening efficiency, sensitivity, specificity, cost-benefit analysis, how much money to spend and how many people to screen before a patient can be diagnosed.
Therefore, you will see that different countries and regions will have different recommendations for the check-up items during the whole pregnancy. Some check-up items are more, while others are less, which is mainly a cost-effective choice.
The prenatal check-up during pregnancy is a model and pioneer of systematic and comprehensive disease screening for the whole population in the history of modern medicine. Many non-pregnant people learn the strategies of disease screening from the prenatal check-up.
At present, during the check-up, the commonly used screening for diseases during pregnancy includes:down syndrome screening,B-ultrasound screening for macromalformation,Preeclampsia screening,Premature birth screening,screening for gestational diabetes mellitus,Thyroid disease screening,Screening for sexually transmitted diseases,GBS screeningWait, I will take the most common Down’s screening as an example to make an introduction for everyone.
In the whole population, the incidence of Down syndrome is about 1/800-1,000. In order to improve the efficiency and reduce the risk, we usually adopt the combination of screening and invasive diagnosis.
That is to say,For a high-risk minorityWe do invasive amniocentesis and karyotype analysis directly.
For normal peopleFirst, we screen the mother’s peripheral blood. For pregnant women with high risk of screening, we do invasive amniocentesis and karyotype analysis.
There are two main screening methods now, one is the traditional and classic screening of maternal peripheral blood biochemical indicators, which is also called ".down syndrome screening",and the other is advanced screening, that is, non-invasive examination of fetal free DNA in maternal peripheral blood, also referred to as".noninvasive”。
Compared with the traditional "Down’s screening", the price of "non-invasive" will be higher, but the detection rate of Down’s syndrome will be higher, and the false positive rate and false negative rate will be lower, which can reduce more unnecessary amniocentesis.
The results of traditional "Down’s screening" will be divided into three categories: high, medium and low risk, or high and low risk. The cut-off value of high risk is usually set at 1/250, and the high risk will be recommended for amniocentesis.
Therefore, if you want to do screening, you need to know a lot of terms related to screening and the meaning behind these terms.
The following terms and meanings are related to Down’s Screening:
Background risk:The probability and risk of Down’s syndrome in the normal population is about 1/800-1,000.
Screening risks:When you do "Down’s Screening", the risk value may be low risk or high risk.
Residual risk:Even if the result of Down’s screening is low risk, it doesn’t mean that everything is fine, and there is still a relatively low risk, which is the so-called residual risk.
Invasive diagnostic risk:If it is a high risk, you will be advised to do amniocentesis. The risk of abortion caused by amniocentesis is about 1-2/1000, which is the additional risk brought by invasive diagnosis itself.
Game theory game theory:Doing "Down’s Screening" is actually betting on probability, that is, making a choice between the above probabilities and making a choice.
In the normal population, the incidence of Down syndrome is about 1/800-1,000. You can choose to do "Down screening" or not.
Some people think that this probability is very low, so they decide not to do it, but what if they win the prize?
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If the result of "Down’s Screening" is that the risk is 1 in 200, the doctor suggests that you do amniocentesis, and the probability of miscarriage is 1-2 in 1,000, do you do it or not?
Which risk are you more afraid of?
Screening or not screening? Do you need an invasive diagnosis? This is betting on probability.
The correct and reasonable choice principle is to look at the high probability, and to consider the balance between income and risk. It is not only the probability that you gamble, but also whether you are willing and able to accept the consequences of gambling loss.
Gamble if you can afford to lose, even if the risk of 1/100 is not high. If you can’t afford to lose, don’t gamble, even if the risk of 1/1000 is too high, you have to be willing to gamble and lose.
With the continuous progress of technology, more and more diseases can be screened. Even for the same disease, more and more screening methods can be selected, and the screening methods are becoming more and more accurate.
Of course, you are facing more and more choices. Are you ready, students who love to struggle?