Many pregnant women and their families are particularly confused about how to choose prenatal screening or prenatal diagnosis, and even some obstetricians and gynecologists are unable to provide prenatal screening or prenatal diagnosis options to pregnant women and their families.
I. Which pregnant women choose Down’s syndrome screening?
Pregnant women younger than 35 years old with no history of adverse pregnancy (spontaneous miscarriage, fetal arrest, stillbirth, stillbirth, neonatal death and birth of malformed children), no family history of genetic disease, and no abnormalities in this pregnancy with a singleton pregnancy are recommended to choose to do Down’s screening.
Time of Down’s syndrome screening: divided into early pregnancy (9 weeks to 13+6 weeks) and middle pregnancy (15 weeks to 20+6 weeks)
Early pregnancy Down’s screening mainly screens for trisomy 21 (Down’s syndrome) and trisomy 18; mid-pregnancy Down’s screening can screen for trisomy 21, trisomy 18 and open neural tube defects (such as anencephaly, open spina bifida, meningeal bulge, spinal membrane bulge, etc.).
Second, which pregnant women need to do amniotic fluid examination?
Pregnant women who have one of the following conditions need to do amniotic fluid examination.
1. age ≥ 35 years old pregnant women;
2. pregnant women with a history of chromosomal abnormalities;
3. if one of the couple is a carrier of a balanced chromosomal translocation or inversion;
4. Pregnant women who may be carriers of an X-linked genetic disorder;
5. Pregnant women with a couple with a single gene disorder or who have given birth to a child with a single gene disorder;
6. Pregnant women with a history of unexplained spontaneous abortion, malformation, stillbirth or neonatal death;
7. Pregnant women with a high risk of Down’s syndrome screening;
8. Pregnant women with fetal abnormalities suggested by ultrasound during pregnancy.
However, pregnant women with contraindications to amniocentesis are advised not to do amniocentesis for the time being: (1) those who have not been cured of preoperative infection or those who have infection or suspected infection on the day of surgery; (2) those with central placenta praevia or placenta praevia or hypoplacenta with bleeding; (3) those who have not been cured of miscarriage first.
Third, which pregnant women are suitable for non-invasive fetal DNA testing?
Non-invasive fetal DNA testing is a more accurate means of prenatal screening, not diagnosis. Pregnant women with high risk of Down’s syndrome need further amniocentesis to confirm the diagnosis.
1. Non-invasive fetal DNA testing is recommended for pregnant women who miss screening and have no indication for amniocentesis;
2. Pregnant women with indications for amniocentesis and contraindications for amniocentesis are recommended to undergo non-invasive fetal DNA testing;
3. Non-invasive fetal DNA testing is recommended for pregnant women with a gray area of prenatal screening risk;
However, some pregnant women are not suitable for non-invasive fetal DNA testing: (1) pregnant women with gestational age less than 3 months; (2) pregnant women with IVF assisted pregnancy; (3) pregnant women with twin or multiple pregnancies; (4) pregnant women with chromosomal abnormalities; (5) pregnant women with indications for amniocentesis and no contraindications for amniocentesis.