What is non-invasive DNA
This test is performed by collecting peripheral blood (5-10 ml) from a pregnant woman, extracting the free DNA from it (which includes placenta-derived fetal DNA), and using next-generation high-throughput gene sequencing combined with bioinformatics to analyze the placenta-derived fetal free DNA and derive the risk rate of fetal diseases with three chromosomal aneuploidies with an accuracy rate of about 90%.
What fetal disorders can be detected by non-invasive fetal DNA testing?
Three common fetal chromosomal aneuploidy abnormalities are currently indicated.
They are Trisomy 21, Trisomy 18 and Trisomy 13.
What are the groups not suitable for non-invasive fetal DNA testing?
1.
What are the chromosomal disorders that are currently unsuitable for non-invasive fetal DNA testing?
1. Chimeric phenotypes in chromosomes (chimerism refers to the inconsistent karyotype of fetal and placental cells)
2. structural abnormalities such as microdeletions, microduplications, or translocation types in chromosomal abnormalities.
3. Sex chromosome abnormalities.
What information do I need to provide to the physician when applying for a non-invasive fetal DNA test?
1. Name of the pregnant woman, date of birth, weight at the time of blood collection, mailing address and contact number of the pregnant woman.
2. Pregnancy and delivery history (including history of bad pregnancy and delivery) and number of fetuses.
3. Provide the date of the last menstrual period for the doctor to verify the gestational week to exclude intrauterine growth restriction of the fetus.
4. providing the results of other prenatal tests, serological prenatal screening or prenatal diagnosis, especially early fetal ultrasound screening or mid-term ultrasound screening
5. whether the couple has chromosomal abnormalities and a family history of monogenic disease
6. whether the conception was assisted reproduction
7. whether cell therapy, allogeneic blood transfusion or whether the patient is a tumor patient, etc. has been performed.
What are the caution groups for non-invasive fetal DNA test?
1. Pregnant women with high risk of prenatal serological screening, advanced age with expected delivery age ≥ 35 years, and pregnant women with other direct prenatal diagnosis indications.
2. Pregnant women with gestational weeks <12 weeks. _
3. Pregnant women with high weight (weight >100 kg).
4. Pregnant women conceived by in vitro fertilization-embryo transfer (double or multiple embryo’s).
5. Pregnant women with double chorionic twin pregnancies.
6. Pregnant women with combined malignancy (e.g. teratoma, etc.).
7. Pregnant women with soft independent imaging screening indicators suggesting a high likelihood ratio of common chromosomal aneuploidy (e.g., nasal bone loss, NF thickening).
1. Pregnant women with a history of delivery of chromosomally abnormal fetuses.
2. One of the spouses has a definite chromosomal abnormality (excluding normal chromosomal variants).
3. The pregnant woman has received allogeneic blood transfusion, transplantation, cell therapy or received immunotherapy within one year, which will cause interference to the results of high-throughput gene sequencing prenatal screening and diagnosis.
4. Fetus with microdeletion microduplication syndrome or other chromosomal abnormalities suspected by fetal imaging (e.g., multiple positive imaging screening soft indicators).
5. People with high risk of various genetic diseases.