What Makes the Maternal Fetal Imaging Program at Hudson Valley Radiology Unique?
What is Down Syndrome?
What is Trisomy 18?
What is the First Trimester Screening: the 11-14 week scan?
What does the First Trimester Screening tell me and my doctor?
What happens if First Trimester Screening shows that I am at increased risk?
How does First Trimester Screening Compare to other ways of determining if my fetus is at risk for a chromosomal abnormality or a structural malformation?
How accurate is First Trimester Screening?
What is Chorionic Villus Sampling (CVS) at 11-14 weeks?
How is CVS done?
What are the risks associated with the CVS test?
What is a “Genetic” obstetrical ultrasound examination?
What patients can benefit from Genetic obstetrical ultrasound?
What makes the 18-22 week Cardiovascular Genetic/Level II Ultrasound program with Hudson Valley Radiology Associates unique?
Consultation with board certified physicians who are subspecialty fellowship trained in high risk Maternal Fetal Imaging.
Accreditation- We are the first providers of 11-14 week First Trimester Screening (accredited by The Fetal Medicine Foundation, London, England) and one of the few private practice maternal-fetal imaging programs who have achieved and maintained accreditation by the prestigious American Institute of Ultrasound in Medicine (AIUM).
Detailed protocols to assess your fetus not only for structural malformations but for the most extensive list of genetic ultrasound “markers”: a partial list includes- middle bone of the pinky finger, widened space between the first and second toes of the foot, ear and nasal bone length, and our unique assessment of cardiovascular Down syndrome markers.
Universal fetal cardiac assessment- approximately 60% of Down Syndrome fetuses and approximately 80% of trisomy 18 fetuses have structural heart diseases. The detection of structural heart disease therefore is a critical requirement of ultrasound risk assessment for chromosomal abnormalities. We are the only private practice providers of genetic obstetrical ultrasound studies whose physicians also have the dedicated expertise in fetal echocardiography (detailed evaluation of the fetal heart).
Quantitative Down Syndrome risk assessment- The end result of your exam will be a number that represents the risk of Down Syndrome or Trisomy 18 that is unique to your fetus. Each patient has their own unique emotional balance sheet that weighs the risk of a chromosomally abnormal baby with the risks and benefits of knowledge gained from an amniocentesis. The purpose of this consultation is to provide the information allowing you to make a decision that is best for you (Do I want or need an amniocentesis?).
Sophisticated Imaging Tools- If a fetal structural abnormality is found, we have the most sophisticated imaging technology including Fetal MR (magnetic resonance imaging) and 3D Ultrasound, to fully analyze the problem so you can be counseled appropriately.
Non-Invasive Screening for Fetal Structural Malformations and Chromosomal Abnormalities: First Trimester Screening at 11-14 Weeks
Brief Overview:
- The vast majority of babies are born normal.
- All women, whatever their age, have a small risk of delivering a baby with a physical and/or mental handicap.
- In some cases the handicap is due to a chromosome abnormality such as Down syndrome (Trisomy 21 or Trisomy 18).
- First Trimester Screening (FTS) gives an estimate of the risk for Down Syndrome. To know for sure whether or not the fetus has a chromosome abnormality, an invasive test is needed (chorionic villus sampling or amniocentesis). However, invasive tests carry a small risk of causing miscarriage.
Down Syndrome is a chromosomal disorder that causes mental retardation and birth defects which may involve the heart and/or digestive tract. Down Syndrome affects approximately one in every 800 babies.
Risks for Downs in Relation to Maternal Age
The table below shows how the chance of having a baby with Down Syndrome increases with age. In the beginning of pregnancy, the risk that the fetus has a chromosome abnormality is higher than at birth because many affected fetuses die naturally during pregnancy.
Maternal age related risks of having a live born child with Down Syndrome and the risk of carrying a fetus with Downs at 12 weeks of gestation.
Risk of Trisomy 21
| Age | At Birth | At 12 Weeks | |||
| 20 | 1 in 1526 | 1 in 1018 | |||
| 25 | 1 in 1351 | 1 in 901 | |||
| 30 | 1 in 894 | 1 in 596 | |||
| 32 | 1 in 658 | 1 in 439 | |||
| 34 | 1 in 445 | 1 in 297 | |||
| 36 | 1 in 280 | 1 in 187 | |||
| 38 | 1 in 167 | 1 in 112 | |||
| 40 | 1 in 96 | 1 in 64 | |||
| 42 | 1 in 55 | 1 in 36 | |||
| 44 | 1 in 30 | 1 in 20 |
Trisomy 18 is a more severe chromosomal disorder which causes profound mental retardation and multiple birth defects. Few Trisomy 18 babies live longer than one year, although some do survive childhood. Like Down Syndrome, the chance to have a pregnancy with Trisomy 18 increases with increased maternal age.
First Trimester Screening consists of a combination of an ultrasound exam and a maternal blood test performed between 11-13 weeks and six days (the crown rump length: 45-84 millimeters) of pregnancy. The ultrasound exam assesses gestational age and looks for major physical defects. Then, the amount of fluid accumulation behind the neck of the baby, called nuchal translucency (NT) is measured. A maternal blood specimen is obtained and analyzed for two chemicals called free beta-hCG (human chorionic gonadotropin) and PAPP-A (pregnancy associated plasma protein-A), which are normally found in the blood of all pregnant women. The results of the ultrasound exam are combined with the results of the blood test to estimate a specific risk level for Down Syndrome and Trisomy 18.
First Trimester Screening can provide helpful information about the possibility of chromosomal disorders and structural malformations. The test alerts you and your doctor that your baby may be at increased risk for one of these disorders. The 11-14 week scan can detect some but not all physical defects. A follow-up ultrasound study at 18-22 weeks with a Cardiovascular Genetic/Level II Ultrasound is recommended to optimize noninvasive ultrasound risk assessment for chromosomal abnormalities and structural malformations. If the ultrasound measurement of the nuchal translucency is enlarged (greater than 2.5 mm) there is an increased risk of structural (anatomic) abnormalities even if chromosome studies (amniocentesis or CVS) are normal. Under such circumstances, we recommend a Cardiovascular Genetic/Level II Ultrasound.
Please remember that if your test result does not fall within the normal range, it only means that further testing (CVS or amniocentesis) may be indicated. Since First Trimester Screening is a screening test, and not a diagnostic test, an abnormal result does not necessarily mean that there is a problem with your baby. Depending on the estimated risk, you may be happy to continue without further testing.
If the First Trimester Screening test indicates an increased risk for chromosome abnormalities, your doctor will refer you for genetic counseling to explain the test results and your options for further testing. These options may include an invasive test such as chorionic villus sampling (CVS) or amniocentesis. The advantage of an invasive test is that it is diagnostic- you get a diagnosis, or definitive answer. The disadvantage is the risk of miscarriage (see discussion later in this overview). Alternatives to invasive testing include additional screening tests which provide a risk estimate for Down Syndrome but are not diagnostic: Modified sequential screen maternal blood test at 15 weeks; Cardiovascular Genetic/Level II Ultrasound, which detects approximately 98% of Down fetuses if both are normal.
How does First Trimester Screening compare to other ways of determining if my fetus is at risk for a chromosomal abnormality or a structural malformation?
Currently, advanced maternal age (AMA, >35 yoa) and an abnormal maternal blood second trimester screen test (15-16 weeks) are the methods used to determine risk and select which patients would benefit from amniocentesis. First Trimester Screening (FTS) has several advantages over these approaches. FTS is more sensitive. For example, FTS will detect 90% of Down Syndrome in comparison to second trimester screen, 60-70% and AMA 20-30%. FTS has significantly less false positive and that means you are far less likely to be exposed to the risks of an invasive procedure (amniocentesis) following a positive FTS in comparison to advanced maternal age (AMA) or a positive second trimester screen.
Our program of First Trimester Screening and 18-22 week Cardiovascular Genetic/Level II Ultrasound is the most sensitive and specific way to non-invasively optimize risk assessment for chromosomal abnormalities and structural malformations.
90% of babies with Down Syndrome and 75% of Trisomy 18 babies will have a positive First Trimester Screening test. In addition, patients carrying babies with other chromosomal disorders or birth defects with other chromosomal disorders or birth defects may have a positive First Trimester Screening. However, a negative First Trimester Screening does not eliminate the possibility that the baby may have Down Syndrome, Trisomy 18 or other chromosomal abnormalities, nor does the test eliminate the possibility of birth defects, mental retardation and other disorders not detectable by prenatal screening. Therefore we recommend that all women have an 18-22 week Cardiovascular Genetic/Level II ultrasound scan. In the majority of cases, no increased risk is found and patients can be reassured that it is unlikely that their baby had Down Syndrome or Trisomy 18.
PLEASE REMEMBER: The decision to have First Trimester Screening is your personal decision. If these tests show that you are at increased risk, it does not mean that your baby has a problem, only that further evaluation of your pregnancy is indicated. In addition, please speak to your doctor about second trimester maternal serum AFP (alpha-fetoprotein) to screen for neural tube defects (NTD’s).
Further information for women who consider having an invasive test
Basic information on invasive tests is provided below. This office provides amniocentesis services in conjunction with genetic counseling. We can provide you the names of several physicians in the region who perform chorionic villus sampling.
The test is offered at 10-12 weeks gestation. This involves the examination of chorionic villi (placental cells). Both the baby and the placenta (afterbirth) develop from the same cell. That is why the cells of the placenta can be used to check the chromosomes of the baby.
CVS can be done from a transabdominal approach or through the cervix. Which technique is used depends primarily upon the particular physician performing the procedure and the location of the placenta.
Trans Abdominal CVS:
Local anesthetic is given. A fine needle is then passed into the uterus through the mother’s abdomen and a sample of cells is taken. The needle is watched carefully with an ultrasound scan to ensure that it does not harm the fetus. The whole procedure takes 2-3 minutes.
Trans Cervical "CVS”
The doctor inserts a thin tube, or a catheter through the cervix into the placenta. When gentle suction is applied, a chorionic villus sample is withdrawn.
Need to repeat the test…
In about 1% of cases, the invasive test will need to be repeated because the cells will not grow in the laboratory or the results are inconclusive.
The risk of miscarriage due to CVS is 1% (1 in 100), approximately twice that of amniocentesis.
Amniocentesis at 15 weeks or later.
Amniocentesis is another invasive test which involves passing a thin needle into the uterus in order to take some fluid from around the fetus. This test gives the same information as CVS but it is carried out at 15 weeks and the results are available 2 weeks later. The risk of miscarriage is 1 in 200 to 1 in 400, about one half that of CVS.
Part II
The 18-22 Week Cardiovascular Genetic/Level II Obstetrical Ultrasound Exam
What is a "Genetic" obstetrical ultrasound examination?
A Genetic obstetrical ultrasound study is one of several noninvasive tools by which a woman’s risk for structural malformations and certain chromosomal abnormalities (in particular Down syndrome, also called Trisomy 21) is assessed. The other non-invasive methods are First Trimester Screening (please see our accompanying brochure), and the 18-22 week Cardiovascular Genetic/Level II Ultrasound examination. These methods assess one’s risk for Down syndrome but only an invasive procedure, either chorionic villous sampling (CVS, performed 10-13 weeks) or amniocentesis (usually performed 15-18 weeks) can definitively diagnose a chromosomal abnormality. These invasive procedures carry the small risk of miscarriage of a normal fetus: CVS, 1:100 (1%); amniocentesis (1:200-1:400 (0.25%-0.5%).
Our 11-14 week First Trimester Screening and the 18-22 week Cardiovascular Genetic/Level II ultrasound studies we perform optimize noninvasive risk assessment for the three most common chromosomal abnormalities- Down Syndrome, trisomy 18 and trisomy 13 and optimize the detection of structural malformations.
It should be considered for all patients:
1. Patients who are 35 years of age or older, who are uncertain as to amniocentesis and desire additional information other than age alone to help them make a decision.
2. Patients less than 35 years of age who have had prior false-positive second trimester maternal serum screen results (abnormal “AFP” test indicating increased risk for Down Syndrome followed by either a normal amniocentesis or the birth of a normal baby.)
3. Patients who desire to optimize noninvasive screening in conjunction with 11-14 week First Trimester Screen and 15-16 week maternal serum screen.
4. Patients with abnormal maternal serum screen who are ambivalent or uninterested in amniocentesis.
(Please note, the American College of Obstetricians and Gynecologists standard of care is to offer amniocentesis for all patients who will be 35 years of age at term or older, or patients with a prior history of a chromosomal abnormality regardless of noninvasive screening test results)
What makes the 18-22 week Cardiovascular Genetic/Level II Ultrasound program with Hudson Valley Radiology Associates unique?
The 18-22 Week Cardiovascular Genetic Level II Ultrasound is a detailed maternal-fetal ultrasound study with advanced cardiovascular protocols that achieves a Down syndrome risk detection rate (sensitivity) of at minimum 90%. When combined with normal first, modified sequential or second trimester quad screen, Down syndrome risk detection may be as high as 99%.
The 18-22 Week Cardiovascular Genetic Level II Ultrasound is a detailed maternal-fetal ultrasound study with advanced cardiovascular protocols that achieves a Down syndrome risk detection rate (sensitivity) of at minimum 90%. When combined with normal first, modified sequential or second trimester quad screen, Down syndrome risk detection may be as high as 99%.
Click to download the brochure: First Trimester Screening at 11-14 Weeks
Click to download the brochure: The 18-22 Week Level II Ultrasound Exam