Prenatal tests help to determine abnormalities in your unborn child as early as the fetal stage of development. Fetal free DNA testing is a prenatal screening test that can identify certain birth defects in the fetus related to abnormal numbers of chromosomes. The test can also indicate the blood type and sex of the fetus.
Fetal free DNA is the genetic material of your unborn child that circulates in the maternal blood during pregnancy. The fetal DNA finds its way into the maternal blood through the placenta. It is found in small quantities during the first trimester and continues to increase during the pregnancy. Genetic tests can be performed using fetal DNA as early as 10 weeks in the pregnancy to detect for any abnormalities.
Fetal free DNA testing is usually recommended for women who have a high risk of giving birth to a baby with certain birth defects such as Down syndrome or trisomy 18. Some of these risk factors include:
- 35 years or older
- Ultrasound that indicates an increased risk of a birth defect
- Previous pregnancy with birth defect
Fetal free DNA screening is performed by taking a sample of blood from your arm any time during or after the 10th week of pregnancy. The blood is sent to the lab for analysis.
A negative test result suggests that it is very unlikely that your baby will have a birth defect. Positive test results indicate an increased risk of having a birth defect. More invasive procedures, such as chorionic villus sampling (CVS) or amniocentesis, may be required to confirm or rule out a specific birth defect.