Results indicate your risk of carrying a baby who has certain chromosomal conditions, such as Down syndrome. This test measures levels of four substances in your blood. During your second trimester, your health care provider will offer another blood test called the quad screen.
In Down syndrome and in certain other conditions, the nuchal translucency measurement is larger than usual. During your first trimester, your health care provider will offer a blood test and an ultrasound to measure the size of the clear space in the tissue at the back of a baby's neck (nuchal translucency). Some diagnostic tests, such as chorionic villus sampling and amniocentesis, carry a slight risk of miscarriage. A diagnostic test is the only way to be sure of a diagnosis. If a screening test indicates a possible problem - or your age, family history or medical history puts you at increased risk of having a baby with a genetic problem - you might consider an invasive prenatal diagnostic test. If results indicate an increased risk for a genetic disorder, your health care provider will discuss your options for a diagnostic test to confirm the diagnosis. Screening tests can't make a definitive diagnosis. Prenatal screening tests are usually offered during the first or second trimester. These tests include blood tests, a specific type of ultrasound and prenatal cell-free DNA screening. Prenatal screening tests can identify whether your baby is more or less likely to have certain birth defects, many of which are genetic disorders. They support their patients by interpreting genetic testing results, providing information on testing options, and emotionally supporting patients undergoing the prenatal genetic testing process.The two main types of prenatal testing are: A prenatal and preconception genetic counselor assists expecting mothers and couples through the process of prenatal screening and prenatal diagnostic testing. Genetic counselors are medical professionals who have completed specialty training in medical genetics and counseling. In general, anyone considering prenatal screening should consider working with a genetic counselor. If you have questions regarding fetal fraction and how it affects NIPT screening, consider speaking with a genetic counselor. Have Questions About NIPT and Fetal Fraction? If you receive a low fetal fraction measurement in your second blood draw, your doctor may recommend alternative methods of prenatal screening. In this case, your doctor may recommend that you repeat the test a little later on in your pregnancy when fetal fraction is more likely to be higher. A low fetal fraction measurement in NIPT testing simply means that there was not enough placental cfDNA to obtain accurate results. If your NIPT results indicate that there was a low fetal fraction, this does not mean that there is a health concern for the fetus. What if my NIPT Results Indicate Low Fetal Fraction? Whether the pregnancy is considered a singleton (one fetus) or a twin (two fetuses): Fetal fraction has been shown to increase by 1.6 fold for twin fetus pregnancies compared to singleton pregnancies. Gestation: Fetal fraction is at its highest between 10 and 21 weeks gestationĬhromosomal abnormalities in the fetus: For example, maternal blood tends to have a higher than average fetal fraction when the fetus has trisomy 21, also called Down syndrome.
Weight: Women who are overweight or obese have lower fetal fraction Fetal fraction varies for each woman and is determined by multiple factors, including:
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