What to Expect at Your Visits
Genetic Testing and Screening
There are several testing options offered to screen for genetic conditions during the pregnancy. These screening tests, meaning they provide information about the probability or chance that the baby may be affected by one of these conditions. They cannot diagnose or rule out these conditions. Ask your provider for more information on the specific conditions mentioned below and screening options that are recommended for you. All of these screenings and tests are optional.
Screening Options
Circulating cell free fetal DNA screening (also known as prenatal cell free DNA, NIPT, or NIPS): This screening test can be done as early as 10 weeks. It is done by taking blood from your arm to look at the DNA from the pregnancy. The screen checks the pregnancy for Down Syndrome (Trisomy 21), Trisomy 13, and Trisomy 18. You have the option to screen for sex chromosome abnormalities which would also allow you to learn the predicted fetal sex. The results of this screen give an increased or decreased risk for the chromosome conditions listed above, but will not give a definite result.
Maternal serum marker screening: This blood test is performed between 15 and 21 weeks. It measures four proteins that are normally found in your blood during pregnancy. This test screens for the risk of Down syndrome, trisomy 18, spina bifida, and anencephaly. You may be referred to a genetic counselor for diagnostic testing if your screening tests show an increased risk for any condition. You may also request a genetic counselor appointment. Just ask your provider for a referral.
Diagnostic Testing:
Chronic villus sampling (CVS) is a diagnostic test performed between 10 to 13 weeks. It involves the removal of a small number of chorionic villi. Chorionic villi is tissue from the developing placenta. The test provides a chromosome analysis and may provide additional information about other potential genetic conditions. Complications leading to miscarriage is the main risk of CVS. It can occur in less than 1 out of every 100 cases.
Amniocentesis involves the removal of a small amount of amniotic fluid from the sac surrounding the baby. It uses a thin needle that is inserted through your belly and uterus. It is typically performed in the clinic between 15 to 23 weeks. Ultrasound is used throughout the procedure. Your baby's cells from the amniotic fluid are tested. Complications leading to a miscarriage is the main risk. It can occur in less than 1 out of every 200 cases.
Carrier Screening:
Carrier Screening is a type of genetic test that can tell you whether you carry a genetic change from certain genetic disorders. Carriers do not have symptoms of the condition but may pass on a genetic change that could result in the condition in their children. The test allows you to find out your chances of having a child with a genetic disorder.
Carrier screening is available for disease including cystic fibrosis, spinal muscular atrophy, and hemoglobinopathies. Your provider will give you more information about these diseases if needed. All three conditions are recessive. Recessive means that both parents must be a carrier of the genetic change in order to potentially have a child with the disease. Hemoglobinopathy screening is most complete when ordering a CBC and hemoglobin electrophoresis or fractionation. These are done by drawing your blood.
