Prenatal Testing: Everything You Need To Know

Medically Reviewed by Dr. K on 21 April 2021

Table of Contents :

  1. Your Guide to Prenatal Testing
  2. Routine Prenatal Tests
  3. Prenatal Genetic Tests
  4. Other Tests
  5. Results
  6. Questions for Your Doctor

Your Guide to Prenatal Testing

 

Prenatal checks provide details regarding your wellbeing and the health of your baby when you are pregnant. They help in the detection of any issues that can concern them, such as birth defects or hereditary diseases. The findings will assist you in making the right health care choices regarding your child both before and after birth. 

 

Prenatal tests are useful, so it’s crucial to understand how to view the results. A favourable test outcome does not necessarily imply that your child would be born with a condition. You should discuss the assessments with the doctor, midwife, or any health care professional to understand what they say and what you should do with the findings after you receive them. 

Prenatal tests are recommended for all pregnant women by doctors. Some women may need further diagnostic testing to rule out hereditary issues.

Routine Prenatal Tests

 

In the first, second, and third trimesters, you will get several pregnancy checks. Some people want to know about your health, and others want to know about your baby. 

 

You’ll get regular tests during your pregnancy to ensure that you’re in good shape. Your health care professional will examine blood and urine tests for the following conditions:

 

  • HIV and other sexually transmitted diseases
  • Anaemia
  • Diabetes
  • Hepatitis B
  • Preeclampsia, a type of high blood pressure

 

They’ll even look at your blood type and see if you have a protein called the Rh factor in your blood cells. You could also receive:

 

  • Pap smear
  • Group B Strep screening: To check for this kind of infection, your doctor can swab the skin in and around your vagina. This normally occurs in the month leading up to your due date.
  • Ultrasound: Sound waves are used to create images of your baby and organs using this technology. If your pregnancy is natural, you’ll get it twice: once at the beginning to determine how far along you are, then then at 18-20 weeks to monitor your baby’s development to ensure their organs are developing properly.

 

Prenatal Genetic Tests

 

Prenatal screening may also be used for doctors to check for symptoms that the baby is at risk for genetic abnormalities or heart defects. You are not required to have these tests, however your doctor can recommend them to ensure the health of your infant. 

 

They’re particularly crucial for women who are at a higher risk of giving birth to a child with a birth condition or a genetic problem. If you answer yes to all of the below questions, this might be you:

 

  • Are you above the age of 35? 
  • Have you ever had a child that was born prematurely or with a birth defect? 
  • Have a hereditary disease or one that runs in your family or in the family of one of your parents? 
  • Do you have a medical condition such as diabetes, elevated blood pressure, seizures, or an inflammatory illness like lupus? 
  • Have you ever experienced miscarriages or stillborn babies? 
  • Have you ever had gestational diabetes or preeclampsia while pregnant?

 

Screening tests are seen with certain maternal genetic tests. They will warn you whether your child has a greater chance of developing an illness or condition, but they can’t guarantee they’ll be born with it. Some “diagnostic" tests will provide you with a more precise response. This kind is usually provided after a positive result on a screening examination. 

 

To begin, your doctor will want to screen you and the other parent for genes linked to diseases such as cystic fibrosis, Tay-Sachs disease, sickle cell disease, and others. Even if you don’t have the disease, if both of you have a gene for one of these diseases in your DNA, you might pass it on to your child. The exam is known as a carrier test. 

 

To search for a genetic problem in your baby, your doctor can use one or more screening tests, such as:

 

Ultrasound. Each of them will be scheduled for you early in your pregnancy to ensure that all is going on. If you’re pregnant with a high-risk baby, you’ll need this test more often. Doctors will use it to examine the back of your baby’s neck from 11-14 weeks. There may be a greater chance of Down syndrome where there are folds or dense skin. Your doctor can sometimes take a blood sample at the same time.

 

Integrated Screening. This test is divided into two sections. The findings of the ultrasound looking at your baby’s neck and the blood samples you had at 11-14 weeks are combined in the first section. Then, between 16 and 18 weeks, they’ll take a second blood sample. Your baby’s chance for Down syndrome and spina bifida, a spinal cord and brain disease, is determined by the results.

 

Sequential Screen. This is equivalent to integrated screening, in that the doctor checks the findings for you immediately following the first phase, which takes place between 11 and 14 weeks. It’s not as reliable as the longer test, but it gives you an earlier indication of your baby’s danger. If the screening reveals that there might be a condition, the specialist will do further testing to determine the exact nature of the problem. If no danger is seen, you’ll most definitely get a second blood test at 16-18 weeks just to be sure.

 

Triple or quadruple screening test. Doctors look for hormones and proteins in the blood that come from your infant or the placenta, the organ that transports oxygen and nutrients to them. The test will scan for three distinct substances (triple screening) or four different substances (quadruple screening) (quadruple screening). If your infant has a certain number of these, he or she is more likely to have a birth disorder or a hereditary illness. This procedure takes place in the second trimester, between 15 and 20 weeks.

 

Cell-free fetal DNA testing. Doctors use this procedure to look for the baby’s DNA in your blood to screen it for Down syndrome as well as two other hereditary disorders, trisomy 18 and trisomy 13. Within 10 weeks of pregnancy, you will get this finished. Doctors don’t advise it for any woman; it’s normally reserved for women who are carrying a high-risk pregnancy. It isn’t possible anywhere, and it isn’t included by any health care plans. Consult the doctor and see if this test is essential.

 

Other Tests

 

If a screening results in a great result, the doctor will use other testing to check for a concern.

 

Amniocentesis. Your doctor will take a sample of the fluid that covers your baby to scan it for developmental abnormalities or birth defects with a small needle inserted into your belly. The treatment is not without consequence. Amniocentesis causes around 1 in 300 to 500 women to miscarry. Your doctor would be able to inform you whether or not anything is essential.

 

Chorionic villus sampling (CVS). Doctors sample a small portion of the placenta by inserting a needle or a small tube into your vaginal canal. They look for Down syndrome and other developmental disorders in the study. Only a small percentage of high-risk women would need this procedure, typically after a scan revealed the possibility of a birth defect. The treatment will inform you if there is a concern for sure, but it still carries a chance of miscarriage equivalent to amniocentesis. Consult the doctor and see if CVS is right for you.

 

Results

 

The results of prenatal tests will assist you in making critical health-care choices. However, keep in mind that all of them will warn you that your child will be born with a disability, but this isn’t guaranteed. There is no such thing as a 100% accurate test. 

 

Discuss the findings with the doctor and what they say. A genetics consultant will also assist you with deciding what to do if you have a favourable outcome, as well as what life would be like with your child if they are diagnosed with a disease.

Questions for Your Doctor

 

If your doctor suggests pregnancy examination, consider the following questions:

  • What is the aim of these tests? 
  • What would the outcomes reveal to me? What are they not going to show? 
  • What if I don’t get the test? 
  • What am I going to do with the results? 
  • What is the accuracy of the tests? 
  • What are the potential risks of these tests? 
  • How long would it take for the results to be received? 
  • What do the tests feel like? 
  • How long should they set you back? 
  • Would they be covered by my insurance? 
  • Would the findings of genetic testing, in particular, be accessible to someone else (such as my insurance company)? 
  • What impact would the outcomes have on my family? 
  • Is it possible to refuse to receive the findings even though the exam has already been completed? 
  • Where can these tests be done?

Sources

Referenced on  10.4.2021

  1. March of Dimes: “Prenatal Care."
  2. Neil Seligman, MD, University of Rochester Medical Center.
  3. childs Health from Nemours: “FAQs: Prenatal Tests."
  4. American College of Obstetricians and Gynecologists: “Frequently Asked Questions- Routine Tests in Pregnancy."
  5. Cleveland Clinic: “Maternal-Fetal Medicine (High-Risk Pregnancy).
  6. Johns Hopkins Medicine: “Common Tests During Pregnancy."
  7. Ryan E. Longman, MD, University of Miami, Miller School of Medicine.
  8. Eunice Kennedy Shriver National Institute of Child Health and Human Development: “How do healthcare providers diagnose birth defects?"
  9. Cystic Fibrosis Foundation: “About CF: What Is Cystic Fibrosis?"
  10. Eunice Kennedy Shriver National Institute of Child Health and Human Development: “The Placenta: A Vital Organ for Baby, Mom and Science."
  11. University of California San Francisco Medical Center: “FAQ: Cell-Free Fetal DNA Testing.”
  12. https://www.webmd.com/baby/your-guide-prenatal-testing#1

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