Ms. Yang (pseudonym), 30, who already has a 4-year-old son, was a twin in her second pregnancy, and a noninvasive DNA test was done at 15 weeks of pregnancy, and the results suggested a high risk of trisomy 21.
Humans have 23 pairs of chromosomes, one from mom and one from dad.
One more, one less, one more, and one less chromosome of the 46 chromosomes will cause different degrees of deformity or defects in the fetus.
If chromosome 21 becomes three, trisomy 21 is also known as Down syndrome.
A high risk of trisomy 21 indicates a high likelihood of fetal malformations or defects.
In general, noninvasive DNA testing is a method of prenatal screening with high accuracy, but further prenatal diagnosis is required.
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Examination to confirm the diagnosis of Down syndrome How should she choose?
As a mother-to-be, Ms. Yang felt more panicked: 99% of the fetuses with high risk of noninvasive DNA results had problems, after all, the children with Down syndrome had various defects and great parenting risks, and she decided to terminate the pregnancy.
At the Eugenic Genetic Clinic of Xi'an People's Hospital (Xi'an Fourth Hospital), the doctor recommended that Ms. Yang undergo amniocentesis for prenatal diagnosis when she was 18 weeks pregnant, because Ms. Yang's twins were double cashmere double sheep, which were decided based on the chromosome test results of the two fetuses.
After 2 weeks, the results of the amniocentesis revealed chromosomal abnormalities in one fetus, and the diagnosis was "trisomy 21", also known as Down syndrome. Another fetal chromosome examination showed no obvious abnormalities.
"Down syndrome" is the most common chromosomal disease caused by an extra chromosome 21. Children with growth and developmental disorders, motor development and sexual development delays. There may be congenital heart disease and other organ defects, and low immunity is susceptible to various infections.
Looking at the test results, Ms. Yang is very entangled in her heart, in fact, she already has a 4-year-old son, this fetus is not normal, and the economic pressure and psychological pressure that the family will face after birth are very large.
After assessment and risk analysis, the doctor told Ms. Yang that the existing medical technology can completely retain the normal fetus. When Ms. Yang was 21 weeks pregnant, she underwent a fetal reduction operation with the help of an obstetrician. At 39+ weeks gestation, Ms. Yang gave birth to a baby girl healthily.
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Which pregnant mothers are prone to "Down syndrome" and how to prevent it?
The incidence of pregnant women aged > 35 years increased significantly. Egg aging of elderly pregnant mothers is an important cause of the occurrence of trisomy 21.
Pregnant women who are exposed to teratogenic substances during pregnancy. For example, during pregnancy, there is exposure to pesticides, benzene, radiation and other teratogenic substances.
Genetic factors. A small number of parents who have given birth to a child with Down syndrome have a higher probability of re-fertility.
Prevent the occurrence of Down syndrome in the following three points:
Avoid giving birth at an advanced age.
Pregnant women ≥ 35 years of age should be diagnosed prenatally in a timely manner.
Pregnant women with a family history, early screening, early detection, and early intervention.
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How do expectant mothers test "Down Babies"?
Early screening: At 9-13+6 weeks of pregnancy, the pregnancy-related plasma protein A and human chorionic gonad hormone concentration in the blood of pregnant women are detected, combined with the age, gestational age, weight, ethnicity, etc. of pregnant women and ultrasound detection indicators, and the risk of fetal suffering from Down syndrome is screened out by evaluation software.
Medium screening: At 15-20+6 weeks of pregnancy, the concentration of alpha-fetoprotein, free estriol and human chorionic gonadotropin in the blood of pregnant women is detected, combined with the pregnant woman's age, gestational age, weight, ethnicity and other indicators, and the risk of fetal suffering from Down syndrome is screened by evaluation software.
Noninvasive DNA testing may also be performed after 12 weeks' gestation to assess the risk of trisomy 21.
Prenatal diagnosis: fetal karyotype analysis by choriocentesis or transabdominal pumping of amniotic fluid. Cell chromosomal examination is the definitive method of prenatal diagnosis of "Down syndrome".
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How to take care of "Down Baby"?
There is currently no effective treatment for Down syndrome.
Children have low immunity and need to pay attention to preventing infection. If other malformations are concomitant, surgical correction may be considered. Long-term education and training can also be carried out to enable children to take care of themselves and slowly adapt to society.
Tang Shi'er is an angel with broken wings, and if they intervene appropriately and undergo rehabilitation training in time, they can also integrate into society, and some of them can also live independently.
Source: Xi'an People's Hospital Xi'an Fourth Hospital
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Editor: Lei Yang
Review: Liang Yuan