Fetal DNA testing can be done as early as 10 weeks. This method is used to screen for chromosomal abnormalities within the fetus. A blood sample and DNA sample will be extracted from both the mother and fetus to check for the following – Down syndrome, trisomy 13 and trisomy 18, and sex chromosome abnormalities. This test has a 99 percent accuracy rate in detecting whether a mother is at risk of having a baby with a chromosomal disorder.
Unlike the first and second trimester screening, the fetal DNA test is recommended to women who have already determined they are at risk. This test is not recommended for women carrying more than one baby or those who have a low risk of having a baby with chromosomal disorders. Women who qualify for the test are those above the age of 35 or those with an abnormal screening test.
Because the test is more specific than the first or second-trimester screening, the fetal DNA test is more accurate in determining chromosomal defects. However, the results will likely vary depending on the lab. If the test results are negative, which means there is no defect than you might not need future testing. This depends on what your doctor recommends you to do. If the results are positive, then you’ll need to decide with your family and your doctor what your next steps should be.