How Is Genetic Testing Done In Pregnancy

How Can I Arrange Carrier Status Screening

Pregnancy: The First Trimester

Carrier screening is usually requested by a doctor, obstetrician, fertility specialist, midwife or genetic counsellor. They will fill out a test request form that you take to your local pathology collection centre for the blood test. The genetic testing will be done in a specialist laboratory.

Make sure you tell the person who is ordering the test if you have a family history of a genetic condition, so they can order the most appropriate test.

In Australia, carrier status screening can cost several hundred dollars per person. You cannot claim any of the money back on Medicare. Some private health funds will pay part of the cost if you have a family history of some genetic diseases.

What If Cvs Is Not Possible

Women with twins or other higher-order multiples usually need sampling from each placenta. However, because of the complexity of the procedure and the positioning of the placentas, CVS is not always feasible or successful with multiples.

Women who are not candidates for CVS or who did not get accurate results from the procedure may require a follow-up amniocentesis. An active vaginal infection, such as herpes or gonorrhea, will prohibit the procedure. In other cases, the doctor may take a sample that does not have enough tissue to grow in the lab, generating incomplete or inconclusive results.

What Are The Risks Of Cvs And How Reliable Is It

The CVS test has a slightly higher chance of miscarriage than amniocentesis, but it has the advantage of being able to be done earlier in pregnancy.

It is a relatively new test and there is not so much information on reliability as with amniocentesis. There is a suggestion that the CVS test may give a confusing result in a small proportion of cases, maybe one in 100.

In such cases it may indicate an abnormality where none exists. Although there is usually additional information which clearly demonstrates that the baby will be abnormal, where doubt still exists it may be necessary for an amniocentesis test also to be carried out later in the pregnancy.

There is also a remote possibility around 1 in 1000 cases that a chromosome abnormality will not be detected.

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Prenatal Genetic Testing: Who May Need It And Why

Many parents worry about whether their unborn child may have genetic conditions that can affect their long-term health or even the infants ability to survive after birth. The process of prenatal genetic testing can determine whether a fetus has certain medical conditions while in utero. Weve put together a guide that can help you better understand genetic testing.

What Is Prenatal Genetic Testing

Noninvasive Prenatal Testing

Prenatal genetic testing gives parents information about genetic disorders or birth abnormalities the fetus may have. Unlike some of the routine prenatal tests like blood type, blood count or glucose screening, these tests are optional. Talk with your healthcare provider and decide which tests are right for you.

Some people decide to get prenatal genetic testing in addition to routine pregnancy testing. Prenatal genetic testing is optional. A persons chromosomes or genes cause genetic disorders. A gene is part of your bodys cells that stores instructions for how your body works. A chromosome holds your genes. Congenital disorders are present at birth, and healthcare providers can diagnose some of these conditions before birth.

There are two different kinds of tests: screening tests and diagnostic tests.

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Who Should Get Genetic Testing

The decision to get prenatal genetic testing is a personal choice. Ask your healthcare provider what they recommend if youre unsure. The results provide important information about the health of the fetus. Healthcare providers offer all pregnant families genetic screening as part of their pregnancy care.

Some of the reasons families will choose diagnostic genetic testing during pregnancy are:

  • Irregular result of a genetic screening test.
  • Family or personal history of genetic conditions.

Why You Might Consider Undergoing Genetic Testing

As you think about whether youâd like any of the genetic tests your healthcare provider offers, consider some of the following reasons for having genetic testing done:

  • Screening tests donât pose any risk to your unborn baby

  • First-trimester screening tests can detect about 85 percent of Down syndrome cases

  • Second-trimester screening tests can detect 80 percent of Down syndrome cases

  • Combined first- and second-trimester screening tests successfully detect 94 to 96 percent of genetic disorders

  • Diagnostic tests can identify more than 99 percent of many disorders however, itâs important to keep in mind that there is a small risk of pregnancy loss associated with these procedures. During diagnostic tests a sample is taken of either amniotic fluid or the placenta.

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Testing For Changes Other Than Gene Changes

  • Chromosomes. DNA is packaged into structures called chromosomes. Some tests look for changes in chromosomes rather than gene changes. Examples of these tests are karyotype and chromosomal microarrays.
  • Gene expression. Genes are expressed, or turned on, at different levels in different types of cells. Gene expression tests compare these levels between normal cells and diseased cells because knowing about the difference can provide important information for treating the disease. For example, these tests can be used to guide chemotherapy treatment for breast cancer.

What Are Kick Counts And How Do You Do Them

Her At-Home DNA Test Revealed a Huge Family Secret

Kick counts is a way for you to track how often your baby moves. By about 5 months of pregnancy, you should start to feel your baby move in your belly. Your baby can turn from side to side and sometimes head over heels. Tell your provider if:

  • Youre at about 20 weeks of pregnancy and havent felt your baby move.
  • Youre worried that your baby isnt moving.
  • You notice a change in how often your baby moves, especially if movement decreases.

Your provider may ask you to do kick counts to see when and how often your baby moves. Here are 2 ways to do kick counts:

  • Every day, time how long it takes for your baby to move 10 times. If it takes longer than 2 hours, tell your provider.
  • See how many movements you feel in 1 hour. Do this 3 times each week. If the number changes, tell your provider.
  • You can do kick counts into your third trimester. If your provider is concerned about your babys movements, they may do other tests to check on your babys health.

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    Whats The Best Dna Test Kit

    You should try to find a provider or genetic counselor near you to perform DNA testing. They will order the correct tests and then talk to you about what they mean. But if you cant go through your healthcare provider, you can get a DNA test kit directly from a DNA testing company. These test kits are called direct-to-consumer genetic tests. The best DNA test kits offer easy-to-understand information about the scientific basis of their tests, but it is risky to use them because there may not be anyone you can speak to personally about the results.

    If you test positive for a genetic condition or find that you have a higher risk of developing a disease, you should call your healthcare provider. They can put you in touch with a genetic counselor who can evaluate you and the information you have and help you decide what to do next.

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    What Is Chorionic Villus Sampling

    The CVS test is carried out earlier then amniocentesis at around the 9th or 10th week of pregnancy, and again it is an outpatient procedure. Rather than testing a sample of the fluid of the mothers womb, this test take a very small amount of material from the developing placenta.

    One way of doing the test is to place a thin tube through the cervix to obtain the sample. Most women say that this is only slightly uncomfortable.

    Another method is similar to the amniocentesis test, and involves placing a needle in the womb and using an ultrasound scanner to guide it.

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    Family Health History Checklist: Planning A Pregnancy

    Gather family history information before seeing the doctor.

    Use the US Surgeon Generals online tool for collecting family histories, called My Family Health Portrait.

    Tell your doctor if you have any family members with a genetic condition, chromosomal abnormality, developmental disability, birth defect, newborn screening disorder, or other problem at birth or during infancy or childhood, especially if you have had a previous pregnancy or child affected by one of these conditions.

    o Talk to those family members, if possible, to find out their specific diagnoses.

    o Ask for a copy of their genetic or diagnostic test results, if any, to share with your doctor.

    Getting Support And Advice

    A Clear Understanding on Preimplantation Genetic Testing

    Planning a pregnancy can cause a lot of worry if you are concerned about a genetic condition that can be passed on to your children. The results of a genetic test can have a major impact on your life and the lives of your family members. You should consider talking to your doctor or getting genetic counselling before going ahead with testing.

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    Prenatal Testing For Down Syndrome

    Down syndrome is a genetic condition caused by extra genes from the 21st chromosome. It results in certain characteristics, including some degree of cognitive disability and other developmental delays. Common physical traits include an upward slant of the eyes flattened bridge of the nose single, deep crease on the palm of the hand and decreased muscle tone. A child with Down syndrome, however, may not have all these traits.

    The incidence of Down syndrome in the United States is about 1 in 1,000 births. There is no association between Down syndrome and culture, ethnic group, socioeconomic status or geographic region.

    Is Genetic Testing Covered By Health Insurance

    Some genetic testing may be included with your health insurance. Your coverage will depend on your policy and in some cases your risk factors, such as being over age 35, a history of genetic issues, or other reasons for testing as deemed necessary by your doctor. You can contact your health insurance provider for the specifics.

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    What To Consider When Deciding Whether To Have Genetic Testing During Pregnancy

    Prenatal testing is optional. You might consider the following risk factors for chromosomal issues or birth defects when making your decision to test:

    • Your age: The risk is higher as you age particularly over age 35.
    • Your ethnicity: People of different ethnic backgrounds may carry a higher risk of certain chromosomal issues and birth defects as well.
    • Your family medical history: If a genetic condition runs in your family, you may be at higher risk of passing on the condition to your offspring.
    • Your pregnancy history: If you have had another child with a genetic condition or birth defect, you may have a higher risk of passing it on to another child.

    Choosing to undergo testing is very personal. On one hand, it gives you time to consider different options or find support if you receive a positive result. On the other, you may not want this information so its up to you and your partner.

    Screening tests usually give a positive or negative result with regard to certain conditions or birth defects. They indicate the potential for issues versus a confirmation of diagnosis.

    Screenings may be performed in the first or second trimester.

    Second Trimester Genetic Screening Tests

    Daughter reveals her surprising DNA test results l WWYD
    • Maternal serum screen: This screening involves a blood test that looks for markers of trisomy 21 , trisomy 18 , or neural tube defects. For the most accurate results, this test should be given between weeks 15 and 17, but it can be done anywhere between 14 weeks and 20 weeks, 6 days.
    • Anomaly ultrasound: This ultrasound looks at your baby from head to toe. Your healthcare professional will look at the size of your babys head and for other potential physical issues. This ultrasound is usually performed between and, yes, its also the scan where you may find out your babys sex.

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    What Does Genetic Testing Look For

    Genetic testing is a type of medical test that identifies changes in chromosomes, genes, or proteins. The results of a genetic test can confirm or rule out a suspected genetic condition or help determine a persons chance of developing or passing on a genetic disorder. In short, it identifies any changes or mutations in a persons DNA that could lead to genetic diseases like:

    • Spina bifida and other neural tube defects
    • Cystic fibrosis

    Diagnostic Testing In Pregnancy

    Diagnostic tests provide more accuracy as well as information about conditions not included in screening.

    We move beyond common chromosomal problems and have the ability to scan for smaller deletions or duplications, Dugan says. This can be particularly informative when certain birth defects are detected on an ultrasound.

    Some women may choose to have these invasive tests without screening. Others, though, could have an abnormal screen and then proceed to a diagnostic test.

    Diagnostic testing options include:

    Chorionic villus sampling: Placenta tissue is extracted via the cervix or by using a needle inserted through the mothers abdomen into the uterus. It is performed between the 10th and 13th weeks of pregnancy. Parents who want a confirmation sooner often choose this option, Dugan says.

    Amniocentesis: Here, a needle is inserted through the abdomen to extract fluid surrounding the baby . The amniotic fluid, which Dugan says is mostly baby urine, contains fetal cells that can be used for diagnostic testing. It is performed 15 weeks into the pregnancy or later.

    There is a risk of miscarriage with these procedures most women who undergo the procedures have no complications.

    Youll hear different risks quoted, but we try to stay pretty conservative, says Dugan, noting that the miscarriage risk quoted by Michigan Medicines Maternal Fetal Medicine is 0.28 percent for chorionic villus sampling and 0.25 percent for amniocentesis.

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    What Else Should I Know

    Scientists are learning more and more about genetics. A worldwide research project called The Human Genome Project created a map of all human genes. It shows where the genes are located on the chromosomes. Doctors can use this map to find and treat or cure some kinds of genetic disorders. There is hope that treatments for many genetic disorders will be developed in the future.

    What Are The Risks Of Screening Tests

    Why The âprenatal Peaceâ Genetic Screening Test? C27

    Screening tests cannot harm you or the baby but it is important to consider carefully whether or not to have these tests.

    Some screening tests in pregnancy can lead to difficult decisions for you.

    For example, screening tests for Down’s syndrome, Edwards’ syndrome or Patau’s syndrome can lead to difficult decisions about whether to have a diagnostic test, such as amniocentesis, that carries a chance of miscarriage.

    A diagnostic test tells you for certain whether you or your baby has the condition.

    If diagnostic tests show your baby has a condition, this can lead to a decision about whether you want to continue or end the pregnancy.

    Having a further test or ending the pregnancy will always be your decision, and healthcare professionals will support you whatever you decide.

    It’s up to you whether or not you choose to have screening tests in pregnancy.

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    Diagnostic Genetic Testing During Pregnancy

    Chorionic villi sampling A small sample of placental tissue is obtained either transcervically or transabdominally under ultrasound guidance between 11-13 weeks of gestation.

    Amniocentesis A small sample of amniotic fluid is removed by placing a needle into the amniotic cavity under ultrasound guidance after 16 weeks gestation.

    Scientific Journal Articles For Further Reading

    Committee Opinion No. 640: Cell-Free DNA Screening For Fetal Aneuploidy. Obstet Gynecol. 2015 Sep 126:e31-7. doi: 10.1097/AOG.0000000000001051. PubMed: 26287791.

    Dondorp W, de Wert G, Bombard Y, Bianchi DW, Bergmann C, Borry P, Chitty LS, Fellmann F, Forzano F, Hall A, Henneman L, Howard HC, Lucassen A, Ormond K, Peterlin B, Radojkovic D, Rogowski W, Soller M, Tibben A, Tranebjærg L, van El CG, Cornel MC. Non-invasive prenatal testing for aneuploidy and beyond: challenges of responsible innovation in prenatal screening. Summary and recommendations. Eur J Hum Genet. 2015 Apr 1. doi: 10.1038/ejhg.2015.56. PubMed: 25828867.

    Goldwaser T, Klugman S. Cell-free DNA for the detection of fetal aneuploidy. Fertil Steril. 2018 Feb 109:195-200. doi: 10.1016/j.fertnstert.2017.12.019. PubMed: 29447662.

    Gregg AR, Skotko BG, Benkendorf JL, Monaghan KG, Bajaj K, Best RG, Klugman S, Watson MS. Noninvasive prenatal screening for fetal aneuploidy, 2016 update: a position statement of the American College of Medical Genetics and Genomics. Genet Med. 2016 Oct 18:1056-65. doi: 10.1038/gim.2016.97. Epub 2016 Jul 28. PubMed: 27467454.

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    Group B Strep Culture

    Group B streptococcus is a type of bacteria found in the lower genital tract of about 20 percent of all women. While a GBS infection does not usually cause problems in women before pregnancy, it can cause serious illness in mothers during pregnancy. GBS may cause chorioamnionitis and postpartum infection. Urinary tract infections caused by GBS can lead to preterm labor and birth or pyelonephritis and sepsis.

    GBS is the most common cause of life-threatening infections in newborns, including pneumonia and meningitis. Newborn babies contract the infection during pregnancy or from the mothers genital tract during labor and delivery.

    The Centers for Disease Control and Prevention recommends screening all pregnant women for vaginal and rectal GBS colonization between 35 and 37 weeks gestation. The treatment of mothers with certain risk factors or positive cultures is important to reduce the risk of transmission of GBS to the baby. Babies whose mothers receive antibiotic treatment for a positive GBS test are 20 times less likely to develop the disease than those without treatment.

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