What is the Serenity prenatal test®? The Serenity prenatal test® measures genetic material (DNA) from a pregnant woman’s blood to look for too few or too many copies of chromosomes (referred to as aneuploidies) in the mother and baby. We all carry 23 pairs of chromosomes (22 pairs of autosomes and 1 pair of sex chromosomes), which are made of DNA, in every cell of our body. The pattern of our DNA determines the genes that code for our characteristics, such as hair and eye colour, and any genetic conditions we may have or carry. Trisomies occur when three instead of the usual two copies of a chromosome are present. The most common chromosome abnormalities include Down’s syndrome (trisomy 21), Edward’s syndrome (trisomy 18) and Patau syndrome (trisomy 13). Sex chromosome aneuploidies are conditions in which there is a change from the usual 2 copies of sex chromosomes in males (XY) or females (XX). All of these conditions may cause mental or physical defects, with different levels of severity. The presence of fetal genetic material in the maternal circulation raises the possibility of using maternal blood to diagnose fetal chromosomal abnormalities which is less risky to the pregnancy than other techniques. This screening test may be an option for you to consider if you have a confirmed singleton or twin pregnancy of at least 10 weeks gestational age, and meet any of the following criteria:
- You are considered to be of advanced maternal age (35 years or older for singleton pregnancies or 32 years or older for twin pregnancies).
- You have an abnormal or “positive” serum screen
- Your ultrasound scan raises concerns or shows abnormalities with growth or development of your baby.
- You have a personal or family history of chromosomal aneuploidies for trisomy 13, 18, 21, or other sex chromosome aneuploidies.
What are my current testing options? There are various screening and diagnostic options available for the common chromosomal conditions. Current screening options can tell you the chance (for example, 1 in 50 or 1 in 5000) of your pregnancy having a certain chromosome problem, but they do not provide a definitive answer. Current invasive procedures such as a chorionic villus sampling (CVS) or amniocentesis can provide a more definitive answer, but they have a small risk of complications, including miscarriage. Chorionic villi sampling (CVS) is a procedure that takes a small amount of tissue from the developing placenta. The tissue is then sent to a laboratory to test the chromosomes. CVS is typically performed between 11 and 14 weeks of pregnancy. CVS is associated with a small risk of miscarriage, 1-2%. Amniocentesis is a procedure that withdraws a small amount of fluid that surrounds the foetus. The fluid is then sent to the laboratory to test the chromosomes. An amniocentesis is usually performed around or after the 15 weeks of pregnancy. Amniocentesis is associated with a small risk of miscarriage, 1%.
What are the advantages of the Serenity prenatal test® over my current options? In comparison to other testing options, the Serenity prenatal test® provides more accurate information than calculating chances (risk scores), and does not carry the risk of complications that an invasive procedure can have. It also:
- Uses just a simple, single blood draw from your arm (other tests require multiple blood samples).
- Can be performed as early as 10 weeks of pregnancy (compared to other methods at 12-14 weeks)
- Tests for trisomy 13, 18, and 21
- Tests for sex chromosome conditions (for singleton pregnancies) or the presence of a Y chromosome (for twin pregnancies)
- Results are available within one week
- Lower false negative rate (0.07%) than alternative test methods such as Harmony.
- Has lower test failure rate (less than 0.1%) than Harmony (~5%)
How do I know the Serenity prenatal test®is effective? The Serenity prenatal test® uses verifi® prenatal test technology from Illumina and has been shown scientifically to be the most sensitive and accurate non-invasive prenatal screening test available (4). This test uses a technology called “massively parallel DNA sequencing” to count the number of copies of certain chromosomes, and then uses a calculation method to determine if there are too many or too few copies of these chromosomes present in your baby. Newlife offers this because we want you to have the best testing possible for your pregnancy.
Do normal Serenity prenatal test® results mean that my baby will be perfectly healthy? No test can guarantee a baby will not have any medical issues. The Serenity prenatal test® only tests for aneuploidies of chromosomes 13, 18, 21, and sex chromosomes (for singleton pregnancies only), if ordered. It does not test for all genetic and non-genetic problems that may be present in a baby. If the test result is “No aneuploidy detected”, indicating a negative result, it does not completely rule out all potential problems with chromosomes 13, 18, and 21, or all sex chromosome aneuploidies in your baby. The Serenity prenatal test® is a highly accurate advanced screening test that is non-invasive. Genetic counselling before and after testing is recommended. Results of “Aneuploidy Detected” or “Aneuploidy Suspected” are considered positive and patients would be recommended to seek further invasive prenatal procedures for confirmation. A negative test does not ensure an unaffected pregnancy. Chorionic villus sampling (CVS) and amniocentesis provide definitive diagnostic information, but the invasive nature of these procedures can raise concern among some patients.
What do my Serenity test® results mean? Your results will tell your doctor whether or not trisomy 13, 18, 21 or sex chromosome abnormalities (if these were ordered) are highly suspected in this pregnancy. In the case of a positive result, your health care provider may discuss what the results mean to you and your baby as well as further testing options for your pregnancy. Your test report will include one of three possible results for chromosomes 13, 18, and 21:
- No Aneuploidy Detected
- Aneuploidy Detected, or Aneuploidy Suspected (Borderline Value). Sex chromosomes will be reported as No
- Aneuploidy Detected, or Aneuploidy Detected. In the case of a twin pregnancy, the Y chromosome presence will be reported as Detected or Not Detected.
- A No Aneuploidy Detected test result means that this test identified the expected number of copies of chromosomes reported.
- An Aneuploidy Detected test result means that this test identified too many or too few copies of one of the chromosomes as seen on the report. This can indicate either a trisomy or a sex chromosome aneuploidy.
- An Aneuploidy Suspected test result means that this test identified more copies than expected of the chromosomesreported. We advise further follow up on this result to obtain more information.
Transfer of your information outside the European Union For the purposes of carrying out the Serenity prenatal test®, your personal information will be transferred outside of the European Union, to the USA. Please be aware that the laws applicable to your personal data in the USA are different from those operating in the UK, where Newlife Clinic is established. If you have any questions about the Serenity®NIPT, please do not hesitate to contact a member of staff on 01372 738932 or email firstname.lastname@example.org. References 1 – http://ghr.nlm.nih.gov/condition/down-syndrome 2 – http://ghr.nlm.nih.gov/condition/trisomy-18 3 – http://ghr.nlm.nih.gov/condition/trisomy-13 4 – DNA Sequencing versus Standard Prenatal Aneuploidy Screening. Bianchi et al. New England Journal of Medicine. 27th Feb 2014