Core tip: Some recent medical events have once again reminded us that although modern medicine has been very developed, medicine still has limitations in many cases. In addition to very difficult complications such as \”amniotic fluid embolism\”, there are also some diseases during pregnancy and childbirth that we can prevent and intervene early. Down syndrome is one of them.
The author of this article is the deputy chief physician of the Obstetrics Department of Guangzhou Overseas Chinese Hospital and an authoritative expert in pre-pregnancy consultation, combined internal medicine treatment during pregnancy, and the treatment of critically ill obstetric patients.
1. The main symptoms of children with Down syndrome are as follows:
Down syndrome, also known as congenital stupidity, is a chromosomal disorder caused by an abnormal number of chromosome 21(3) in humans. The current level of medical technology cannot cure and prevent it. The main prevention method is to carefully monitor the labor process to avoid giving birth to a child with Down syndrome.
The main characteristics of children with Down syndrome are mental retardation, delayed physical development and special facial features. Children with wide-set eyes, low nose bridge, small eye fissures, upward sloping eye corners, adjacent inner folds, small external ears, narrow hard palate, tongue often sticking out of the mouth, excessive salivation; short stature, small head circumference, often lagging bone age, and The teeth are delayed and often misaligned; the hair is soft and less; the limbs are short and small, the joints can be excessively bent due to loose ligaments, the fingers are thick and short, and the little finger is bent inwards. Children with Down syndrome can have abnormalities in various parts of the body: congenital heart disease and digestive system abnormalities are the most common. The prevalence of congenital heart disease is as high as 40%, especially ventricular septal and endocardial cushion defects. Digestive organ abnormalities, such as congenital esophageal atresia, duodenal stenosis, anal atresia, etc. Others include: the prevalence of cataracts is 2%, the prevalence of acute leukemia is 1%, the prevalence of thyroid disease is 3%, the prevalence of epilepsy is 10%, transient myelocyte hyperplasia, cornea and lens abnormalities. Myopia, hyperopia, blurred vision, tear duct obstruction, etc., overflow otitis media, which easily causes otitis media to accumulate fluid in the inner ear, affecting hearing, etc. However, there are a small number of children with Down syndrome who do not have body organ malformations.
Children with Down syndrome have special facial features and low intelligence. They may even be unable to take care of themselves and need to be cared for by others throughout their lives. Children with Down syndrome have a short life expectancy, usually around 10-20 years.
2. Who are at high risk for children with Down syndrome?
Some people say: There is no problem with my first child, and there will be no problem with the second one. Some people say that since we are healthy and well-educated, we do not need to be screened for Down syndrome. Some people say that there have been no problem children in our family for generations, and disaster certainly will not befall me. In fact, these are all flukes. Every pregnant woman is at risk of giving birth to a baby with Down syndrome, but the risk varies from person to person. Down syndrome was not associated with a couple\’s number of pregnancies, education level or health status. Relatively speaking, the following groups of people are more likely to be pregnant with Down syndrome than the normal group.
1. The older you are, the greater the riskbig. Pregnant women over the age of 35 are 100 times more likely to have a child with Down syndrome than those over the age of 25;
2. Pregnant women who have given birth to a child with Down syndrome are 10 times more likely to give birth to a child with Down syndrome again;
3. Prenatal ultrasound examination reveals fetal abnormalities, especially heart, kidney and intestinal abnormalities, and fetal bones are shorter than normal. Children with Down syndrome are a high-risk group. In short, all children whose prenatal ultrasound screening detects fetal malformations and chromosomal abnormality markers are high-risk groups for children with Down syndrome;
4. High-risk groups for serological screening;
5. There is a history of congenital stupidity in the family.
3. How to screen children with Down syndrome during prenatal examination?
At present, the international screening methods for Down syndrome are very mature, and experienced experts can even rule out children with Down syndrome through ultrasound.
The current standard screening methods for Down syndrome include ultrasound, blood tests and combined ultrasound + blood screening methods:
Showtime:
1. Blood drawing and ultrasound screening in the early pregnancy (11-13+6 weeks);
2. Second trimester blood screening (14-21 weeks);
3. If fetal abnormalities and chromosomal abnormality markers are found during mid-trimester ultrasound, the results of Down syndrome ultrasound screening should be considered abnormal.
Early pregnancy Down syndrome screening is currently recognized internationally as a very effective screening method. It is a combined method of drawing blood from the mother (free hCG and PAPP-A) and observing the fetus via ultrasound (NT, etc.). Combining the mother\’s age, history of Down syndrome and other factors to comprehensively calculate the risk of Down syndrome in this pregnancy, the accuracy can reach 90% or even more than 95%, that is, 100 children with Down syndrome can be born in 90-95 years. Check it out.
Taking maternal blood to test for Down syndrome (free hCG, AFP and estrogen E3) in the second trimester should actually be a remedy for missed Down syndrome screening in the first trimester. Currently, this method is favored in our country due to its economic applicability and simplicity. It is accepted by many hospitals and pregnant women and has become the main screening method for Down syndrome in many hospitals. However, many pregnant women often question the necessity and accuracy of Down syndrome screening during outpatient visits. This is because screeners use different machines and methods, and the screening time is different, resulting in a decrease in Down syndrome screening accuracy. Inaccurate calculation of gestational age can also affect test results. If non-standard detection methods and reagents are used based on the impact of economic benefits, the false positive rate (high risk rate) will increase. At the same time, some blood samples cannot be sent for testing within 24 hours after collection or the blood storage conditions are not suitable. It can also lead to false positives. Motivation increases. This is also the main reason why many pregnant women have objections to the necessity and accuracy of Down syndrome screening. Screening accuracyIf it is low, it will inevitably lead to a decrease in the final diagnosis rate. Of course, everyone will also question the necessity of this screening. The positive screening rate of this method is about 60%-65%, that is, about 60-65 out of 100 children with Down syndrome are screened. If the inspection methods and reagents are not standardized, the results will be difficult to evaluate.
The final conclusion of several Down syndrome screenings is a ratio, that is, the probability of a child suffering from Down syndrome, rather than a confirmed diagnosis. High risk means that a child has a higher chance of developing Down syndrome than the normal population, but it does not mean that a child with Down syndrome is necessarily a child. Low risk does not absolutely rule out a child with Down syndrome, but the chance is smaller because even 1 in 10,000 is a risk. If the risk is judged to be high, prenatal diagnosis should be used to determine whether the child is truly Down syndrome.
All in all, the results of early pregnancy ultrasound and blood combined screening for Down syndrome are relatively reliable. If it is high-risk, you must ask the bottom line. If the risk of blood testing in the second trimester is high, ultrasound examination should be combined to decide whether to perform invasive prenatal diagnosis.
4. How to deal with the high risks of Down syndrome screening?
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Some pregnant women are worried and even shed tears because of the high risk of Down syndrome screening, mistakenly thinking that the high-risk child is Down syndrome. There are also pregnant women who turn a blind eye to the high risks and take it lightly, thinking that the pie falling from the sky will not fall on their heads. These ideas are wrong. There was a case in which a highly educated couple gave birth to children with Down syndrome three times.
Therefore, if it is high-risk for early pregnancy screening, you should adopt a positive attitude and cooperate with the doctor to do a chorionic villus biopsy to check the fetal chromosomes for a clear diagnosis as soon as possible. If the second-trimester blood screening is high-risk, mid-trimester ultrasound malformation screening should be done between 19 and 23 weeks to observe whether the fetus has abnormal ultrasound performance, and amniocentesis should be done before 24 weeks to check fetal chromosomes. If you miss the above examination time and still suspect Down syndrome, amniotic fluid or umbilical cord blood should be taken after 24 weeks to confirm the diagnosis. Whether it is taking chorionic villi, amniotic fluid or umbilical cord blood to detect fetal chromosomes, it is an invasive prenatal diagnosis. It is relatively easy to obtain amniotic fluid. Other methods require doctors to have higher technical skills, but the results are equally reliable. For the fetus, chorionic villus examination is safer because the sampling needle does not need to enter the amniotic cavity where the fetus lives. At the same time, chorionic villus examination can know the results as early as possible, reducing the psychological burden of fear on pregnant women.
The complication rate of various puncture operations is 0.5%-2%, most of which are miscarriage, infection, premature rupture of membranes, premature delivery, and intrauterine fetal death. The incidence of complications is related to the technical level of the doctor. But complications will occur in every hospital, which is a natural law like colds and fevers.