Amniotic fluid chromosome testing is one of the most commonly used prenatal diagnostic techniques in mid-trimester achieved by amniocentesis. It is used for prenatal diagnosis of fetal chromosomes and congenital metabolic disorders.
I. The following pregnant women should have amniotic fluid chromosome examination
1.Pregnant women whose expected age of delivery is R 35 years old;
2.Pregnant women who have given birth to chromosomal abnormal children;
3, one of the couple has chromosome balance translocation;
4.History of congenital malformation;
5. Carriers of sex-linked recessive genes;
6.Pregnant women who have congenital metabolic diseases or who have given birth to a sick child;
7.History of exposure to teratogenic substances in early pregnancy;
8.Pregnant women with hereditary family history or history of consanguineous marriage;
9. Pregnant women with unexplained miscarriage, stillbirth, abnormal fetus or history of neonatal death;
10. Pregnant women with excessive amniotic fluid, low amniotic fluid, developmental restriction, etc., suspected of having malformations during pregnancy;
11. Pregnant women with a high risk of Down’s syndrome screening during pregnancy;
12. Pregnant women with fetal abnormalities detected by ultrasound examination during pregnancy.
The best time for amniocentesis
Generally, it is 16-23 weeks and 6 days, with 18-23 weeks and 6 days being the best, when the amniotic fluid volume is moderate.
Which pregnant women cannot have amniocentesis
Pregnant women who are suitable for amniocentesis cannot do it in the following cases.
1.Premature miscarriage (abdominal pain, vaginal bleeding, blood in the leukorrhea, brown discharge, vaginal discharge and other symptoms);
2.Two body temperatures (axillary temperature) higher than 37.2℃ before surgery;
3. Platelets ≤ 70×109 (with bleeding tendency);
4, coagulation function test has abnormal;
5.Signs of pelvic or uterine infection;
6, non-medical need for simple gender identification.
Amniocentesis is dangerous?
Amniocentesis is an ultrasound-guided extraction of 10-20 ml of amniotic fluid in a sterile environment, which is relatively safe and the risk of fetal miscarriage is less than 1%.