Remember to consider the family health history of both potential parents, not just mom. Be sure to discuss any concerns with your doctor. Based on your family health history, your doctor might refer you for genetic counseling. Other reasons for genetic counseling include having had. After genetic counseling, you might decide to have genetic testing for conditions that could affect your baby. Results from these tests could impact your pregnancy planning. Testing before you get pregnant can give you time to think about what the results mean for you and consider all your options.
Parents can have a baby with a genetic disease even though neither parent has it. A negative result means that your fetus is at lower risk of having the disorder compared with the general population. It does not rule out the possibility that your fetus has the disorder.
Diagnostic testing with CVS or amniocentesis that gives a more definite result is an option for all pregnant women. Your obstetrician or other health care professional, such as a genetic counselor , will discuss what your screening test results mean and help you decide the next steps.
With any type of testing, there is a possibility of false-positive results and false-negative results. A screening test result that shows there is a problem when one does not exist is called a false-positive result. A screening test result that shows there is not a problem when one does exist is called a false-negative result. Your health care professional can give you information about the rates of false-positive and false-negative results for each test. It is your choice whether to have prenatal testing.
Your personal beliefs and values are important factors in the decision about prenatal testing. It can be helpful to think about how you would use the results of prenatal screening tests in your pregnancy care.
Remember that a positive screening test tells you only that you are at higher risk of having a baby with Down syndrome or another aneuploidy.
A diagnostic test should be done if you want to know a more certain result. Some parents want to know beforehand that their baby will be born with a genetic disorder. This knowledge gives parents time to learn about the disorder and plan for the medical care that the child may need.
Some parents may decide to end the pregnancy in certain situations. Other parents do not want to know this information before the child is born. In this case, you may decide not to have follow-up diagnostic testing if a screening test result is positive. Or you may decide not to have any testing at all. There is no right or wrong answer. Amniocentesis : A procedure in which amniotic fluid and cells are taken from the uterus for testing. The procedure uses a needle to withdraw fluid and cells from the sac that holds the fetus.
Aneuploidy: Having an abnormal number of chromosomes. Types include trisomy, in which there is an extra chromosome, or monosomy, in which a chromosome is missing.
Aneuploidy can affect any chromosome, including the sex chromosomes. Down syndrome trisomy 21 is a common aneuploidy. Others are Patau syndrome trisomy 13 and Edwards syndrome trisomy Carrier Screening: A test done on a person without signs or symptoms to find out whether he or she carries a gene for a genetic disorder.
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. You will normally get the test results back in 2 to 4 weeks. If both you and your partner are carriers of a faulty gene, it does not mean your baby will definitely be affected. You can talk to your doctor or a genetic counsellor about the best course of action. This might involve more tests, IVF if you are not already pregnant, or tests in early pregnancy such as the non-ivasive pre-natal blood test NIPT chronic villus sampling CVS or amniocentesis.
If the carrier status screening test is positive, it is still up to you whether you go ahead and conceive a child or avoid having children. A genetic counsellor can give you the information you need to make the decision. If you have more questions, call Pregnancy, Birth and Baby on to talk to a maternal child health nurse. Learn more here about the development and quality assurance of healthdirect content.
Read more on Garvan Institute of Medical Research website. Introduction to a series of articles developed to provide a behind the scenes look at clinical laboratories. Your first doctor visit, scheduled pregnancy check-ups, tests, ultrasounds and genetic screening. Read more on NT Health website. The principle of screening is to offer a safe, accessible test to identify women with an increased chance of having a baby affected by a chromosomal or genetic condition.
Understanding Genetic Testing Genetic testing may be considered for many different reasons and should always be discussed with a health professional.
Read more on NSW Health website. If you have a strong history of cancer in the family, genetic testing can be used to determine if you have the faulty gene. Find out more here. Read more on Cancer Council Australia website.
They usually do not have symptoms or have only mild symptoms. If both parents are carriers of a recessive gene for a disorder, there is a 25 percent 1-in-4 chance that their child will get the gene from each parent and will have the disorder. There is a 50 percent 1-in-2 chance that the child will be a carrier of the disorder—just like the carrier parents. If only one parent is a carrier, there is a 50 percent 1-in-2 chance that the child will be a carrier of the disorder. Carrier screening involves testing a sample of blood, saliva, or tissue from the inside of the cheek.
Test results can be negative you do not have the gene or positive you do have the gene. Typically, the partner who is most likely to be a carrier is tested first. If test results show that the first partner is not a carrier, then no additional testing is needed.
If test results show that the first partner is a carrier, the other partner is tested. Once you have had a carrier screening test for a specific disorder, you do not need to be tested again for that disorder. Some people decide to have carrier screening before having children.
Carrier screening also can be done during pregnancy. Getting tested before pregnancy gives you a greater range of options and more time to make decisions. Carrier screening is your choice. You can choose to have carrier screening, or you can choose not to. There is no right or wrong choice.
Some of these disorders occur more often in certain races or ethnic groups. For example, sickle cell disease often affects people of African descent. But anyone can have one of these disorders. They are not restricted to these groups. All women who are thinking about getting pregnant or who are already pregnant are offered carrier screening for cystic fibrosis, hemoglobinopathies , and spinal muscular atrophy SMA. You can have screening for additional disorders as well.
There are two approaches to carrier screening for additional disorders: 1 targeted screening and 2 expanded carrier screening.
In targeted carrier screening, you are tested for disorders based on your ethnicity or family history. If you belong to an ethnic group or race that has a high rate of carriers for a specific genetic disorder, carrier screening for these disorders may be recommended.
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