In this article:
What Is Genetic Testing During Pregnancy?
Genetic testing during pregnancy may help determine whether or not the baby has a genetic condition. There are many sorts of genetic tests available, each providing distinct information.Types Of Genetic Tests During Pregnancy
Prenatal genetic testing is a broad phrase that includes both genetic screening and diagnostic tests. While both kinds of testing seek for specific genetic markers, they vary significantly in how they are conducted and what the findings signify.Genetic screening tests
There are many sorts of tests that may be performed at different stages of pregnancy. The procedure begins with a genetic screening test. Screening tests only measure the likelihood of a genetic condition and do not give diagnostic information regarding the baby's health or well-being. In other words, they may predict the presence of a problem but cannot confirm its existence.The results of these tests may be misleading, as per experts. Reports on genetic screening often use the terms "positive" or "negative," however it would be far more suitable for them to say "increased risk" or "decreased risk" followed by a probability. Essentially, the findings of these tests are not definite, but they might help parents determine if they want to pursue more testing for more conclusive answers.
Prenatal genetic screening tests may include:
- First-trimester screening: This is done between 10 and 13 weeks of pregnancy and comprises a blood test and nuchal translucency screening through ultrasound. The results of both tests are combined to assess the risk of Down syndrome, other chromosomal abnormalities, and potential heart, bone, and/or abdominal wall issues.
- Second-trimester screening: This is another two-part test, consisting of a blood test and an ultrasound. The blood test, which may be performed between 15 and 22 weeks of pregnancy, checks for the risk of Down syndrome, Edwards syndrome, and neural tube abnormalities (NTD). The ultrasound is conducted between weeks 18 and 22 of pregnancy and looks for abnormalities in the baby's limbs, heart, brain, spine, abdomen, and facial characteristics.
- Screening throughout both the first and second trimesters: This is sometimes referred to as an "integrated" screening; it occurs when the results of all four screening tests are combined with factors such as a mother's age and weight to produce slightly more accurate screening results. Because it includes first and second-trimester testing, the findings of a combination screening are not accessible until 18 to 22 weeks gestation.
- DNA testing in the absence of living cells: This blood test, also known as noninvasive prenatal testing (NIPT), may be administered as early as 10 weeks of pregnancy. It extracts the baby's DNA from the mother's blood and screens for Down syndrome, Patau syndrome, Edwards syndrome, and chromosomal abnormalities.
Diagnostic genetic tests
A diagnostic test is a direct test of the cells from the pregnancy and can determine with a high level of accuracy whether a pregnancy is affected by a genetic condition.Diagnostic testing varies from prenatal genetic screenings not just in terms of accuracy, but also in terms of invasiveness. Furthermore, unlike screens, which are conducted at a routine prenatal exam, diagnostic tests are performed by an expert, frequently outside of your OB-gyn office.
There are two types of diagnostic genetic testing, both with a low risk of miscarriage. This is the reason why a lot of individuals begin with screening tests and, if the findings are alarming, proceed to diagnostic testing.
The testing choices are:
- Amniocentesis: This sort of diagnostic test may be conducted at any time after the 15th week of pregnancy and has a 99.9 per cent accuracy rate in predicting whether the baby has a chromosomal genetic disorder, such as Down syndrome. This approach may also be used to screen for neural tube abnormalities like spina bifida and hereditary illnesses like cystic fibrosis. The procedure involves introducing a tiny needle through the mother's belly into the amniotic sac to retrieve a fluid sample. This surgery has a less than 1% chance of miscarriage.
- Chorionic villus sampling (CVS): This procedure is often done between 10 and 13 weeks of pregnancy and includes inserting a tiny needle through the belly or a catheter through the cervix to obtain a small tissue sample from the placenta. The sample is then analysed for chromosomal disorders such as Down syndrome or particular genetic testing, with an accuracy rate of around 99 per cent; there is a 1 per cent possibility of miscarriage.
Who Should Get A Genetic Test?
The decision to undergo prenatal genetic testing is entirely personal. If you are uncertain, ask your healthcare professional what they suggest. The findings are essential for understanding the foetus's health. All expectant families get genetic screening as part of their prenatal care.Families may select diagnostic genetic testing during pregnancy for many reasons, including:
- An irregular result from a genetic screening test
- Genetic disorders may run in the family or on a personal level
- Pregnancy above the age of 35
- History of miscarriage or stillbirth
How Do They Do Prenatal Genetic Testing?
The majority of prenatal genetic testing tests the pregnant person's blood. If the screening test results show a high chance of a congenital problem, your doctor will order more invasive testing to detect particular disorders. Amniocentesis and CVS are invasive diagnostic techniques.Is There A Risk To Genetic Testing During Pregnancy?
Prenatal tests do not pose any harm. There is a slightly higher risk if you proceed with diagnostic testing such as amniocentesis or CVS. The dangers of these tests include infection, haemorrhage, and miscarriage.There is no correct or incorrect response when it comes to prenatal genetic testing. The choice is entirely up to you and your family. If you have any concerns regarding prenatal testing or need clarification on what each test looks for, speak with your healthcare practitioner. They will be able to help you weigh the risks and advantages of all genetic testing and make the best option for you and your family. Remember, most kids are born healthy, but it is important that you understand your choices and the genetic testing that is available to you.
FAQs on Your Guide to Genetic Testing During Pregnancy
- What is the 12-week genetic testing?
First-trimester combination screening test. This test combines the findings of a blood test at around 10- 12 weeks with an ultrasound at 11- 13 weeks followed by blood tests. The test will determine your risk of having a kid with Down syndrome or Trisomy 18. - Do I need genetic testing when pregnant?
No, this is not essential. It is a personal decision based on your beliefs or medical history. Some parents wish to know whether their baby will be born with a problem so that they may arrange their care accordingly.
