Get help deciding whether to have prenatal screening

  • What genetic conditions you can get tested for
  • Deciding whether to get tested
  • Types of genetic conditions
  • Types of prenatal screening
  • Benefits and harms of screening or not

If you're pregnant, you can have tests to tell you the chances that your unborn baby may have certain genetic conditions that we call birth defects.


  1. What genetic conditions you can get tested for

    Prenatal tests cannot tell you for sure whether or not your baby has any genetic conditions, only the chance of it happening.

    We'll tell you in language such as 1 chance in 1,000 or 1 chance in 20.

    You can get your unborn baby tested for:

    • Down syndrome, which is called trisomy 21.
    • Edwards syndrome, which is called trisomy 18.
    • Patau syndrome, which is called trisomy 13.
    • Neural tube defects, such as spina bifida and anencephaly.

    What an ultrasound can detect

    When you're deciding whether to have testing, it's helpful to know that the detailed ultrasound you'll have at 19 to 20 weeks into your pregnancy will detect most cases of:

    • Edwards syndrome;
    • Patau syndrome; and
    • neural tube defects.

    Ultrasounds are not able to detect Downs syndrome.


  2. Deciding whether to get tested

    It's up to you whether you have prenatal screening. To help make your decision:

    • use this guidance; and
    • talk to your health care provider.

    The information you get from testing can help you decide whether to:

    • prepare for a child with special needs;
    • offer the child for adoption; or
    • consider ending the pregnancy.

    Doing and not doing prenatal testing are both good decisions.

    Making the decision might be easier if you:

    • base your decision on the best scientific information available;
    • share your thoughts with your doctor, midwife and your family; and

    base your decision on your values and preferences.

    Questions to ask yourself

    • Do I want to know the chance of my baby being affected by one of these conditions?
    • How would I use this information?
    • How might doing the screening test affect my feelings during the pregnancy?

    Talk to your health care provider

    When you talk to your health care provider about prenatal screening make sure you understand:

    • what the tests are for;
    • how and when you get the results;
    • your options for further testing if your result shows a high risk;
    • what your private pay options are; and
    • the benefits and harms of the tests.

    Guide to help you decide

    Use the aid to decision making for prenatal screening document to help make your decision. As well as including the information on this web page it contains:

    • definitions of terms;
    • a place to make notes;
    • a place for you to list the benefits and harms of the options;
    • information about sex chromosome anomalies; and
    • guidance on how to make sure you're comfortable with your decision.

    In this document we also list the references we used for this information and the authors of the aid to decision making.

    Chances related to age

    The chance that your baby will have a genetic condition increases with your age.

    An exception is that the chances of your baby having neural tube defects are 1 in 1,000, whatever your age.

    If you're 25

    • The chance your child will have Down syndrome (trisomy 21) is 1 in 2,500.
    • The chance your child will have Edwards syndrome (trisomy 18) is 1 in 25,000.

    If you're 30

    • The chance your child will have Down syndrome (trisomy 21) is 1 in 840.
    • The chance your child will have Edwards syndrome (trisomy 18) is 1 in 8,400.

    If you're 35

    • The chance your child will have Down syndrome (trisomy 21) is 1 in 356.
    • The chance your child will have Edwards syndrome (trisomy 18) is 1 in 3,650.
    • The chance your child will have Patau syndrome (trisomy 13) is 1 in 5,000.

    If you're 38

    • The chance your child will have Down syndrome (trisomy 21) is 1 in 166.
    • The chance your child will have Edwards syndrome (trisomy 18) is 1 in 1,660.
    • The chance your child will have Patau syndrome (trisomy 13) is 1 in 2,000.

    If you're 40

    • The chance your child will have Down syndrome (trisomy 21) is 1 in 94.
    • The chance your child will have Edwards syndrome (trisomy 18) is 1 in 940.
    • The chance your child will have Patau syndrome (trisomy 13) is 1 in 909.

     


  3. Types of genetic conditions

    About Down syndrome (trisomy 21)

    Down syndrome or trisomy 21 is when a baby has an extra copy of chromosome 21, which affects how the baby develops and grows.

    • People with trisomy 21 have:
      • almond-shaped eyes and a round face;
      • poor muscle tone;
      • greater risk of vision and hearing problems;
      • heart, stomach and bowel defects; and
      • intellectual disabilities that can be mild or moderate.
    • 60% of children with trisomy 21 need specialized home care.
    • Some adults with trisomy 21 have jobs and are almost completely independent.
    • People with trisomy 21 can have meaningful emotional relationships and lead lives that are fulfilling for themselves and their family and friends.

    About Edwards syndrome (trisomy 18)

    Edwards syndrome or trisomy 18 is when a baby has an extra copy of chromosome 18.

    • Many pregnancies with trisomy 18 will miscarry.
    • Babies that are born with trisomy 18 rarely live more than a few days or months because of serious heart and brain defects and poor growth before and after birth.
    • 50% of babies born with trisomy 18 survive beyond their first 6 to 9 days and about 12% of babies survive the 1st year of life.

    About Patau syndrome (trisomy 13)

    Patau syndrome or trisomy 13 is when a baby has an extra copy of chromosome 13.

    • Many pregnancies with trisomy 13 will miscarry.
    • Due to multiple serious medical defects, only 5 to 10% of babies born with trisomy 13 will live to 1 year of age.

    About neural tube defects

    An "open" neural tube defect is when the brain or spinal cord does not form properly.

    • Spina bifida is a type of neural tube defect when the spine does not completely close.
    • People with spina bifida may have both physical and mental disabilities.
    • Anencephaly is an open neural tube defect involving the brain. A baby with anencephaly will be stillborn or die shortly after birth.

  4. Types of prenatal screening

    There are 2 types of non-invasive prenatal screening tests available in Yukon:

    • Serum Integrated Prenatal Screening (SIPS); and
    • the Non-Invasive Prenatal Test (NIPT).

    Information from your ultrasound

    You can also get information from the detailed ultrasound scan you'll have at 19 to 20 weeks into your pregnancy. This ultrasound will be able to detect most cases of:

    • Edwards syndrome;
    • Patau syndrome; and
    • neural tube defects.

    Serum integrated prenatal screening

    Serum integrated prenatal screening (SIPS) tells you if you have a higher chance of carrying a baby with:

    • Downs syndrome;
    • Edwards syndrome; or
    • a neural tube defect.

    To get a serum integrated prenatal screening test, you'll need to give 2 blood samples:

    • The 1st between week 9 and the end of week 13 of your pregnancy; and
    • the 2nd between week 15 and the end of the week 20, preferably between 15 and 16 weeks.

    You'll get your test results about 10 days after your 2nd blood test.

    If the chance is high for either Down syndrome or Edwards syndrome, your doctor or midwife will offer you a:

    • non-invasive prenatal test (NIPT); or
    • an amniocentesis.

    What's an amniocentesis?

    An amniocentesis is a prenatal test we can do when your baby is at a higher risk of having an abnormality.

    A health care professional will insert a needle through your abdomen to take a small sample of fluid around the baby. They will use ultrasound images to guide them as they work. here's a risk of about 1 in 200 that the test cause a miscarriage.

    We sometimes refer to an amniocentesis as an "amnio".

    Non-invasive prenatal test

    A non-invasive prenatal test (NIPT) is more accurate than serum integrated prenatal screening. It identifies whether you're at high risk for having a baby with:

    • Down syndrome;
    • Edwards syndrome; or
    • Patau syndrome.

    To get a non-invasive prenatal test, you'll need to have a single blood test any time after 10 weeks of pregnancy.

    You'll get your test results in about 10 days.

    The non-invasive prenatal test does not screen for neural tube defects.

    If you choose to have a non-invasive prenatal test, you'll be screened for neural tube defects through your detailed ultrasound at 19 to 20 weeks into your pregnancy.

    If your results show that you have a high chance of having a baby with:

    • Down syndrome;
    • Edwards syndrome; or
    • Patau syndrome, your doctor or midwife will offer you an amniocentesis to confirm the result.

    Sex chromosome anomalies

    A non-invasive prenatal test can also tell you the risk of your baby having certain sex chromosome anomalies (SCA). This is when a baby is missing an X or Y chromosome or has an extra chromosome.

    • This type of disorder is fairly common and can affect a baby's development and health.
    • People with sex chromosome anomalies can lead fulfilling lives and develop meaningful relationships.

    You can find out more about sex chromosome anomalies in the aid to decision making for prenatal screening.

    Health coverage

    The non-invasive prenatal test is only covered by the Yukon Health Care Insurance Plan if you're at higher risk for having a baby with:

    • Down syndrome;
    • Edwards syndrome; or
    • Patau syndrome.

    You're higher risk if you're:

    • 35 years or older when your baby is born;
    • pregnant with twins; or
    • your serum integrated prenatal screening results say you're higher risk.

    We may also consider other factors in rare situations.

    If you're not high risk but want to have a non-invasive prenatal test instead of serum integrated prenatal screening, you'll need to pay the $495 cost.


  5. Benefits and harms of screening or not

    Doing and not doing prenatal screening are both good choices. This information can help you make the choice that's best for you. 

    Because ultrasound scans are able to detect most cases of Edwards syndrome, Patau syndrome and neural tube defects, we focus here on the benefits and harms of screening for Down syndrome.

    Ultrasounds cannot screen for Down syndrome.

    Serum integrated prenatal screening

    Benefits

    • You'll know your chances.
      • Out of every 5,000 people screened, 500 people have a result that says they're at higher risk for carrying a baby with Down syndrome.
      • If these 500 people also have a non-invasive prenatal test or an amniocentesis to know for sure, only 13 of them would actually be carrying a baby with Down syndrome.
    • You can prepare for a child with Down syndrome.
      • Some people who know they're carrying a baby with Down syndrome will choose to continue the pregnancy and can prepare for the child or they may consider an adoption plan.
    • You can prepare to end a pregnancy.
      • Some people who know they're carrying a baby with Down syndrome will choose to end the pregnancy.
    • You'll be reassured.
      • Out of 5,000 people who take the test, 4,500 people are reassured by a result that means they're at low risk for carrying a baby with Down syndrome.
    • There's no risk.
      • This is an extremely safe test. There's no risk that this test will cause harm to your baby.

    Potential harms

    • There's risk of a false alarm.
      • Out of the 500 people whose screening results show they're at increased risk of carrying a baby with Down syndrome, 487 are not in fact carrying a baby with Down syndrome. This can create a lot of anxiety.
    • You'll experience anxiety waiting for the results.
      • People waiting for test results have anxiety levels 10 times higher than normal.
    • You may have to face difficult decisions.
      • The 500 people whose screening results show they're at increased risk of carrying a baby with Down syndrome will need to decide about having further testing.
      • People who have testing and are shown to have a baby with Down syndrome will need to make a decision about whether to continue with or end the pregnancy.
    • You may be falsely reassured.
      • Of the 4,500 people whose screening results show they're at low risk for carrying a baby with Down syndrome, 2 will in fact be carrying a baby with Down syndrome.

    Non-invasive prenatal test

    Benefits

    • There's a high detection rate.
      • The detection rate for Down syndrome is greater than 99%. Most babies with Down syndrome will be detected.
    • You can prepare for a child with Down syndrome.
      • Some people who know they're carrying a baby with Down syndrome choose to continue the pregnancy and can prepare for their child. Others may consider an adoption plan.
    • You can prepare to end the pregnancy.
      • Some people who know they're carrying a baby with Down syndrome will choose to end the pregnancy.
    • You'll be reassured.
      • People who have this test and get a low risk result are reassured.
    • There's no risk.
      • This is an extremely safe test. There's no risk that this test will cause harm to your baby.

    Potential harms

    • There's risk of a false alarm.
      • Although the rates for false positives are low at less than 0.1%, someone could get a positive result which is in fact false. This can cause unnecessary stress.
    • You may have to face difficult decisions.
      • People who are faced with a positive test result must make a decision about whether to continue with or end the pregnancy.
    • You may be falsely reassured.
      • False negative results can happen; this means that a person who tests negative is actually carrying a baby with Down syndrome. This happens rarely, but these people are falsely reassured.
    • You may get inconclusive results.
      • About 3% of tests do not give a clear result. This may cause people high levels of stress and anxiety. If you're in this situation, you can get further testing.
    • You may need to pay for the test.
      • Since the Yukon Health Care Insurance Plan only covers this test if a pregnancy is considered high risk, people with a low risk pregnancy will need to pay for the service. Or they may choose serum integrated prenatal screening or to not have any screening.

    Not doing any prenatal screening

    Benefits

    • It avoids anxiety and extra testing.
      • Some people would not consider having any invasive testing or terminating a pregnancy whatever the result of the testing.
    • You can stay true to your personal convictions and values.
      • For some people, not doing the test is the right choice for their personal or family’s convictions.
    • You can avoid decisions about continuing or ending a pregnancy.
      • Not doing the test can avoid the anxiety and stress of making a decision about continuing or ending the pregnancy.

    Potential harms

    • Not knowing your risk of carrying a baby with Down syndrome.
      • Out of 5,000 people who do not have any screening, 15 are carrying a baby with Down syndrome. These people do not have the knowledge to prepare for giving birth to a baby with Down syndrome.
    • Anxiety from not knowing.
      • People who do not take the test may be anxious because they do not know if their child will have Down syndrome or not.
    • Social pressure.
      • People may feel pressured by society to get screened.