Today is March 21, about every 20 minutes in the mainland there is a "Tang Bao" born, due to the huge population base, the number of "Tang Bao" born every year should not be underestimated, as a mother-to-be and father-to-be it is necessary to understand what is "Tang Bao" and how to effectively avoid the recurrence of tragedy, which is related to the happiness of every family.
What are the characteristics of "Tang Bao"?
01 Special face
Babies with Down syndrome generally have a special face, and at birth they can obviously have a special face, such as wide eye distance, small fissure, and oblique outer corner of the eye, opacity of the lens, low and flat nose bridge, smaller outer ear, and often open mouth and tongue, drooling more, smaller and rounder skull, wider skull slit, larger fontanelle, and usually fontanelle is relatively closed, delayed, hair is soft and very rare, neck is relatively short, often sleepy, can be accompanied by obvious feeding difficulties.
02 Mental retardation
Mental retardation, developmental delay, intelligence is only equivalent to children around 4 years old, life can not take care of themselves.
03 There are many complications
Congenital heart disease can usually be accompanied by congenital heart disease, as well as congenital gastrointestinal malformations, visual impairment, and complications of hypothyroidism.
04 Fertility is limited
Male "Tang Bao" can not have fertility until adulthood, and female "Tang Bao" has menstruation after adulthood and may have certain fertility, but it is not recommended that "Tang Bao" have offspring.
Under what circumstances is it easy to give birth to "Tang Bao"?
01 Advanced age to give birth
The vast majority of them originate from the inseparation of chromosome 21 when the mother's egg is formed. The decline of ovarian function is positively correlated with the increase of age, due to the aging of the ovaries of elderly pregnant women, germ cells or fertilized eggs are prone to chromosomal non-separation or chromosomal aberrations when the cells divide. So whether you have a first or a second child, don't be too late!
02 Genetic factors
In a few cases, the birth of "Tang Bao" is caused by genetic factors, such as the presence of chromosomal balance translocation between husband and wife, there is a certain chance of having "Tang Bao".
03Environmental factors
The long-term living environment of pregnant women will have a certain impact on the fetus. For example, under the influence of harmful chemical, physical and pharmaceutical factors for a long time, it is possible to deform the fetus. If during the pregnancy preparation, the mother works for a long time in a bad environment, lives, and is exposed to harmful substances for a long time, such as chemicals and radiation-emitting life appliances, more or less will definitely cause certain harm to the pregnant woman's body, causing some adverse symptoms and diseases, which are the causes of the fetus suffering from Down's disease.
04 Other factors
Pregnant women who take certain medications in the first trimester of pregnancy, or other conditions such as infection in the first trimester, may also lead to the birth of "Tang Bao".
How to avoid fertility "Tang Bao"
01 Births of appropriate age
As mentioned earlier, advanced age fertility is one of the most common reasons for the occurrence of "Tang Bao", so giving birth at the right age can effectively reduce the risk of giving birth to "Tang Bao".
02 Prenatal screening and prenatal diagnosis
Down's screening
Down screening, short for Antenatal screening test for Down syndrome, is a test of special significance. The objective is to determine the risk factor of fetal folly and neural tube defects in the fetus by testing the blood of pregnant women, detecting the concentration of fetal protein, chorionic gonadotropin and free estriol in the maternal serum, and combining the age, weight and gestational age of pregnant women.
Maternal peripheral blood fetal free DNA prenatal screening (noninvasive DNA)
Non-invasive DNA detection technology can accurately obtain the risk rate of fetal chromosomal aneuploidy, that is, trisomy 21-, trisomy 18, and trisomy 13- syndrome by collecting 8mL of pregnant women's peripheral blood, extracting free DNA, using a new generation of high-throughput sequencing technology, combined with bioinformatic analysis. Noninvasive DNA testing is 12 to 22 weeks and 6 days of pregnancy, and the accuracy of noninvasive DNA is much higher than that of Down screening, up to more than 95%.
Non-invasive PLUS
Noninvasive PLUS adds 17 common fetal chromosome aneuploidy, a relatively high incidence of 7 microdeletive diseases larger than 3Mb in size and located at the location of specific syndrome-related chromosome fragments, and 76 fetal chromosome large fragment deletion/duplication syndromes greater than 10Mb.
Karyotype analysis of amniotic fluid cells
For the diagnosis of high-risk pregnant women with fetal screening for Down syndrome, amniotic fluid cell karyotype analysis after amniocentesis is the "gold standard". The most commonly used technique is amniocentesis, in which a fine needle is used to extract amniotic fluid from a pregnant woman's abdomen under ultrasound guidance, followed by chromosomal analysis. Suitable for pregnant women within 18 to 24 weeks of the second trimester.
Since advanced age is currently the only identified risk factor for increased birth risk in Down's infants, it is generally recommended that advanced pregnant women go directly to prenatal diagnosis without blood screening, including villus biopsy in early pregnancy and amniocentesis in the middle trimester. The 21-3 physical examination rate of amniotic fluid puncture is 100%, which is a diagnostic method, not screening.
Heard that the third generation of test tubes can screen for Down syndrome?
The above down syndrome screening method belongs to the diagnosis method during pregnancy, that is, when there is a problem with the obstetric examination during pregnancy, the fetus is miscarried, which will cause great harm to the mother's body and psychology at this time.
The third generation of test tubes takes the genetic material of the embryo before the embryo is implanted in the uterus, diagnoses whether there is an abnormality, screens for healthy embryo transfer, and avoids the birth of a baby with Down syndrome. And that's not all, third-generation IVF mainly includes embryo genetic screening (PGS) and diagnostic (PGD) techniques.
PGS is based on the existing assisted reproductive technology to implant embryos for chromosomal aneuploidy and chromosomal copy number variation detection, in order to select chromosome normal embryos for implantation, thereby improving the success rate of assisted reproduction and reducing the incidence of birth defects. PGS can screen not only for Down syndrome, but also for aneuploid abnormalities and copy number variants in all 23 pairs of chromosomes.
For known and clear chromosomal abnormalities carriers, embryos can be detected and diagnosed through PGD technology, embryos with normal phenotypes can be transferred, in addition, PGD can also be diagnosed for single-gene genetic diseases with known clear pathogenic genes, such as congenital deafness, progressive muscular dystrophy, albinism, hemophilia, etc., effectively reducing the occurrence of birth defects.
![Pay attention to Down's screening to nurture healthy babies[fig]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)