Services and Procedures
First Screen© involves an ultrasound examination and a blood test. The ultrasound is used to measure an area in the back of the fetal neck called the nuchal translucency (NT). A blood test is then performed to analyze specific chemicals produced during early pregnancy. The measurement of the NT and the chemicals in the blood are then combined in a formula to provide two risk estimates: a risk for Down syndrome (trisomy 21) and a risk for trisomy 18. This is a screening test, not a diagnostic test, which means it provides only an estimate of risk. First Screen© does not provide information for neural tube defects (spina bifida).
First Screen© can detect approximately 83 – 85% of babies with Down syndrome and 80% of babies with trisomy 18.
Integrated screening, a combination of First Screen© and quad screening, is a two-part process beginning between 10 - 13 weeks of pregnancy and concluding after the 16th week of pregnancy. The screening requires two visits. By combining the information obtained through both visits, risks are provided for Down syndrome, spina bifida, and trisomy 18.
Integrated screening can detect approximately 92% of babies with Down syndrome, 90% of babies with trisomy 18, and 80% of those with open neural tube defects.
If the NT cannot be obtained due to fetal position, the woman is given the option of serum (2 blood tests without NT) integrated screening, which has 87% detection rate for Down syndrome.
Sequential screening follows the same testing pattern as integrated screening, but allows for preliminary results to be available following the initial visit, with final results available after the 16th week of pregnancy.
Sequential screening can detect approximately 90.4% of babies with Down syndrome, 90% of babies with trisomy 18, and 80% of those with open neural tube defects.
Down syndrome (trisomy 21)
Down syndrome is a chromosome abnormality resulting from the presence of an extra chromosome 21. It is a common genetic cause of mental retardation and may be associated with other health problems.
Open neural tube defects (spina bifida)
Spina bifida is a condition where a portion of a baby’s spine does not close properly. The condition may result in paralysis, lack of bowel and bladder control, curvature of the spine, and abnormalities of the brain.
Trisomy 18 is a chromosome abnormality due to the presence of an extra chromosome 18. It results in significant mental retardation and multiple birth defects. Most babies will not survive with this condition.
Patients who are identified at a higher risk are “screen positive.” Results are discussed with each woman who receives a positive screen. Some patients will then opt for a diagnostic test (chorionic villus sampling or amniocentesis). If results are “screen negative,” indicating a decreased risk, results will be shared by either the maternal fetal medicine staff or your obstetrical provider.
Level II Ultrasound
A level II ultrasound examination, also referred to as a “targeted ultrasound,” examines the structure (anatomy) of a baby and can also evaluate the placenta and umbilical cord, as well as determine the level of amniotic fluid. This non-invasive examination is most often performed around 18 - 20 weeks of pregnancy, and can detect many types of birth defects, although not all problems can be seen or identified. Women who are not considered “high-risk” may have a level II ultrasound examination performed for reasons such as family history or previous pregnancy with a maternal or fetal complication.
Biophysical Profile (BPP)
A biophysical profile is a test of fetal well-being that involves evaluating an unborn baby’s movements, tone, practice breathing movements, and amniotic fluid level by ultrasound. Each element of the test is scored as 2, meaning present, or 0, meaning absent. The BPP is a tool used during the third trimester and may be combined with a non-stress test which evaluates the baby’s heart rate pattern. BPP scores that are not reassuring indicate a need for closer observation or delivery.
Amniocentesis is a diagnostic test offered after 15 weeks of pregnancy during which a thin needle is placed into the pregnant woman’s uterus to withdraw a small sample of the amniotic fluid from around the baby. Fetal skin cells floating in the amniotic fluid are tested for chromosomal abnormalities and other genetic conditions. Analyzing other contents of the amniotic fluid by the same method late in pregnancy can help determine whether a pre-term baby's lungs are likely to be mature and functioning if birth is earlier than expected.
Chorionic Villus Sampling (CVS)
Chorionic villus sampling, a diagnostic test available only between 10 and 12 weeks of pregnancy, involves placing a needle into the pregnant woman’s uterus to sample a small amount of placental tissue. This tissue can be tested for chromosomal abnormalities and other genetic conditions. While CVS offers genetic information earlier than amniocentesis, this test does not provide information on neural tube defects such as spina bifida.