Genetic Testing

Options – Genetic Testing

At Stark Women’s Center we provide genetic screening and testing to give you and your baby the best chance at a healthy life. These tests can provide insight into severity and treatment for birth defects, chromosomal abnormalities and genetic disorders.

Understand that all of these tests are optional and are performed only if elected by our patients. Our team of specialists is always available to discuss the advisability of performing any genetic screening and counseling is recommended for those with questions about abnormal results and whether your baby is at increased risk of having a birth defect.

Sequential (serum) Integrated Screening

Sequential Screening tests for genetic abnormalities and open neural tube defects, such as anencephaly and spina bifida. It also can detect Down syndrome and trisomy 18, which are chromosomal abnormalities. It is a noninvasive test performed in two steps during the first and second trimesters, providing a preliminary result, then a final result. Sequential Screening leads to detection of about 90% of Down syndrome and Trisomy 18 cases and 80% of open neural tube defects.  An abnormal result does not mean the baby has any birth defect, nor does a “negative” test guarantee a baby without one of these defects. If your screen is “positive”, your doctor may suggest further testing, including a targeted ultrasound, Chorionic villus sampling (CVS)* or Amniocentesis*. 

What to expect: At 10 to 13 weeks gestation – a blood sample and an ultrasound that looks for increased fluid build-up at the back of your baby’s neck, which is common in babies with Down Syndrome. Preliminary results show whether you are at increased risk. A second blood test at 15 to 18 weeks provides final results.

Quad Screen

The Quad screen tests for open neural tube defects, Down syndrome, and trisomy 18 by looking at levels of four hormones in your blood, alpha-fetoprotein, human chorionic gonadotropin, unconjugated estriol and inhibin. The detection rate is 75% to 80%, and while a “positive” result does not necessarily mean your baby has one of these birth defects, abnormal readings provide an opportunity to consider genetic counseling and further testing, including ultrasound and amniocentesis.*

What to expect: A blood sample at 15 to 22 weeks gestation to measure hormone levels.

MaterniT21plus

The MaterniT21plus tests for common and rare chromosomal abnormalities, including trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome). It tests your blood for increased levels of hormones that typically occur in these birth defects and is more than 90% accurate. The test can be done as a primary screen or after a positive serum screen test. The MT21 also can detect the sex of your baby.

What to expect: A blood sample after 10 weeks gestation to measure hormone levels.

Alpha-fetoprotein (AFP) Test

An AFP test measures the amount of AFP present in your blood. Often part of a quad screen in the second trimester of pregnancy, it tests primarily for neural tube defects, including spina bifida and anencephaly, but it also can detect chromosomal abnormalities.

What to expect: A blood sample between the 14 and 22 weeks gestation to measure AFP and hormone levels.

Amniocentesis*

Amniocentesis is a prenatal diagnostic test that may be recommended after an abnormal serum, triple or quad test that could indicate you are at increased risk of having a baby with birth defects. It may also be recommended based on your health history and genetic concerns. It is usually done between 14 and 20 weeks gestation, but in certain cases may be recommended as early as 11 weeks. The test studies cells and chromosomes in the amniotic fluid to detect chromosomal abnormalities, neural tube defects, and genetic disorders. It may also detect health problems, including lung development. It is 99% accurate. An amniocentesis is usually performed to confirm results of a previous test or when there is reason to believe your baby could have health problems. Risk of miscarriage is about 0.5% above the naturally occurring rate for women who have this test.

What to expect: Your doctor uses an ultrasound to guide insertion of a needle through the abdomen into the amniotic sac to withdraw a sample of amniotic fluid. The procedure takes about 45 minutes and is usually done at 15 to 18 weeks gestation.

Chorionic Villus Sampling (CVS)*

Chorionic Villus Sampling is a prenatal test that may identify such chromosomal problems as Down syndrome as well as genetic diseases, such as cystic fibrosis, Tay-Sachs disease, and sickle cell anemia. It also determines the sex of you baby to help in identifying disorders that are more common to one sex. Your doctor will obtain and test a small sample of cells called chorionic villi, which are found in the placenta. The test is generally done when there is a family history or higher than normal chance of a genetic disorder and it is 98% accurate. Risk of miscarriage is about 1% above the naturally occurring miscarriage rate for women who have this test.

What to expect: Your doctor uses an ultrasound to guide insertion of a small catheter into the vagina through the cervix. In the case of a newly developing placenta, he may insert a needle through the abdomen. The tissue sample is drawn through a syringe. This procedure is done at 8 to 12 weeks gestation.

*Genetic counseling is always recommended prior to additional testing, including CVS or Amniocentesis, to discuss risks and benefits.