Genetic Testing and Screenings

Initially, expectant mothers would spend nine months before finding out if they had a girl or a boy. Well, that game is completely outdated today. Likewise, you can gauge if you are a carrier for genetic diseases that could be passed on to your unborn baby. At Gyn LA, we offer different genetic testing and screening options before conception and during the first and second trimester. Our team of Los Angeles doctors can also help you in understanding the various testing options, how inheritance works, and birth defects. This will help you make an informed decision about your genetic testing results and pregnancy as well as allow you to learn about the condition before the childbirth.

An Overview of Genetic Testing and Screenings

Why is it essential to integrate genetic testing and screening? According to a report released by the Centers for Disease Control and Prevention (CDC), genetic disorders are the second leading cause of infant mortality between infants between one (1) and four (4) years. It is also the third leading cause of fatality among minors aged between fifteen and seventeen years. The predetermination of genetic tendencies can assist in the preventive management of potential chromosomal abnormalities and diseases such as cancer.

It is worth noting that genetic testing is different from genetic screening. The latter involves measuring the degree of risk for genetic ailments in a fetus. It is known as population-based screening. For instance, African Americans are at an increased risk of suffering sickle cell disease because they have a specific gene.

Genetic testing, on the other hand, is performed based on genetic screening. It involves more rigid tests. If you suspect you have a disease gene because of family history, your doctor will perform a genetic test.

The screening test assesses the probability or level of risk that a fetus could have certain birth defects. That means the test does not diagnose the fetus with any disease. To get more information, the doctor could recommend follow-up tests like Chorionic villus sampling (CVS) or amniocentesis.

8 Reasons Why Your Doctor May Suggest Genetic Testing

Discussed below are the reasons why your doctor may suggest genetic testing or counseling:

  • Expectant mothers above thirty-four years of age- Your chances of getting a baby with chromosomal issues like Trisomy increases if you are above thirty-four years. Children born of fathers of advanced age are also at an increased risk for new dominant genetic mutations (caused by a defect which does not run in his family).
  • A typical prenatal test gave an abnormal outcome- Your doctor could suggest genetic testing in case the test shows a probable genetic issue.
  • You have had two or more miscarriages- Serious chromosome issues in the baby can sometimes result in a spontaneous miscarriage. Numerous miscarriages are an indication of a genetic problem.
  • You have delivered a stillborn baby with a genetic illness physical signs- Most severe genetic diseases cause distractive and specific issues.
  • A baby has medical conditions which could be genetic- When your baby has medical conditions involving at least one body system, genetic testing could assist your doctor find the cause as well as make a diagnosis.
  • A couple intends to have a baby, and one of the spouses or a relative suffers from an inherited disease- Some individuals are carriers of genetic diseases even if they do not show symptoms of the disease themselves. It occurs because some genetic health conditions are recessive. They could cause signs only if you inherited two (2) copies of the disease gene, one from each parent. That means if you inherited a disease gene from one of your parents but a normal gene from the other parent, you will not have signs of the recessive disease. However, you'll have a fifty percent possibility of passing the illness gene to your babies.
  • You already have a baby with a severe birth defect- Not every baby with a birth defect has a genetic issue. Sometimes, infection, physical trauma, poison (toxin) before birth could result in birth defects. The cause is unknown. The fact that a baby has a genetic issue, it does not always mean the issue has been inherited. It could happen due to an unintentional mistake in the baby's cells, not your cells.
  • A baby has medical issues that are genetic syndrome- A genetic testing can validate the diagnosis. Sometimes it could also assist in understanding the severity or kind of genetic disease. It could also help your doctor in getting the most effective treatment.

What are the Different Types of Genetic Testings?

If you are contemplating to get pregnant or you are expectant, genetic testing gives you a comprehensive overview of your baby's health as well as your health.  Some tests check a fetus for medical health conditions while in your womb while others check their deoxyribonucleic acid (DNA) for genetic ailments.

Moreover, a genetic carrier screening (before pregnancy) can examine both parents' genes to determine if their baby will have a genetic condition.

Although most genetic tests are optional, they can assist you in making an informed decision. Additionally, you will understand what to expect once the child is born.

Discussed below are different genetic test options (this will help you choose the test that suits your needs best).

Before Conception

Genetic Carrier Screening Test

If you have a disorder gene but do not have the genetic condition, you are a carrier. The test helps you know if either you or your spouse have a disorder gene. If so, there is a likelihood you will pass the condition on your babies. In most cases, testing is advisable for only one parent. Testing for the second parent becomes necessary if the first test tests positive.

Although you can take the test before or at the time of the pregnancy, it is advisable beforehand.

Your physician will take your saliva or blood samples for testing. Then the laboratory will search for disorders' genes such as cystic fibrosis, sickle cell, spinal muscular atrophy, Tay-Sachs, and fragile X syndrome.

Individuals from certain ethnic groups are likely to be carriers for specific conditions. Therefore, you should confirm with a doctor if you are at an increased risk of being a carrier. For instance, individuals with Ashkenazi or Eastern European background are more likely to suffer from diseases like Canavan and Tay-Sachs. Non-Hispanic whites are at high risk of having cystic fibrosis, whereas sickle cell affects persons with Southern Asian, Mediterranean, and African background.

However, some health conditions are not limited to specific geographic or ethnic backgrounds. Most people today are of mixed backgrounds hence making it difficult to make a recommendation based on geographic or ethnic origin. According to the American College of Obstetricians and Gynecologists (ACOG), all expectant mothers or those planning to get pregnant ought to get screened for:

  • Spinal muscular atrophy
  • Thalassemia
  • Sickle cell
  • Cystic fibrosis

Screening Tests Conducted During the First Trimester

Once you conceive, any experienced doctor will recommend checking the fetus for the risk of medical conditions. Common tests performed in your first three months of pregnancy include:

Sequential Screen

A sequential screen uses a blend of blood tests and ultrasound to check for the likelihood of having Trisomy 18, brain and spine challenges, and Down Syndrome. Typically, the test is carried out between ten and thirteen weeks of the pregnancy. In case your results are not positive, you may have more screening tests in the second trimester.

Cell-Free Fetal DNA Testing

Some of the child's DNA is located in the parent's blood. After ten weeks, the doctor will take your sample and test the fetus' DNA for signs of challenges with the sex chromosomes, Trisomy 18, Down Syndrome, and Trisomy 13.

Should the screening test reveal a birth defect risk, the doctor will recommend a diagnostic test to validate the results.

It is worth noting that the screening test in question does not search for challenges with the spine or brain. Therefore, if you want to know, you should undergo another blood test in the second trimester.

Integrated Screening

Integrated screening is a mix of blood tests and ultrasound to search for Trisomy 18, brain and spine challenges, and Down Syndrome. It is performed during the twelfth week, and the second part of the test occurs during the second trimester.

Although it takes longer to get results, integrated screening is more precise than the sequential screen.

Non-invasive Prenatal Testing

NIPT is a non-invasive blood screening test. Although NIPT doesn't screen for neural tube defects, it is more accurate in noticing chromosomal abnormalities such as Down Syndrome. It is because it directly examines the baby's DNA circulating in your bloodstream.  It is safest after nine weeks.

Moreover, it can determine the baby's sex and blood type.

It can be done together with an ultrasound provided you are thirteen weeks pregnant and below. In case the result shows an issue, the odds are your medical expert will recommend more decisive diagnostic tests like amniocentesis or CVS.

NIPT is ideal for mothers well-thought-out as high-risk for genetic conditions or older than thirty-five years.

Ensure you discuss your options with your gynecologist. What worked for your loved one may not work for you.

Screening Tests Conducted During the Second Trimester

During this stage of the pregnancy, the doctor the following tests:

Maternal Serum Quad Screen

The maternal serum quad screen is a blood test that searches protein in the blood. It could be an indication that the child is at an increased risk of having Trisomy 18, brain or spine challenges, and Down Syndrome.

As the name suggests, it measures four (4) substances found in the blood, namely:

  • Unconjugated estriol (uE3)
  • Human chorionic gonadotropin (hCG)
  • Inhibin A
  • Alpha-fetoprotein (AFP)

Usually, this test is conducted between fifteen and twenty-one weeks.


In week twenty, your doctor can use sound waves to take pictures of the fetus. The photos will be used to check for defects such as:

  • Kidney issues
  • Heart challenges
  • Cleft palate

Integrated Screening

If you underwent the first part of the integrated screening test in the first trimester, you are supposed to have another test. The blood test should be between the sixteenth and eighteenth week.

Chorionic Villus Sampling and Amniocentesis

These diagnostic tests are used to check your baby before she/he is delivered for birth defects like:

  • Trisomy 13
  • Down Syndrome
  • Trisomy 18
  • Challenges with spine or brain growth such as spina bifida (CVS cannot defect these conditions)

Moreover, the tests can show genetic disorders. The tests are above ninety-nine percent accurate. 

Most expectant mothers do not take screening tests. The tests carry an insignificant risk of resulting in a miscarriage. Additionally, mothers who get tests that do not reveal any issue are comfortable depending only on the results. However, the tests aren't one hundred percent accurate. Therefore, if you want accurate tests or the screening results reveal that the fetus could have birth defects, the doctor could suggest taking either of the diagnostic tests.

Chorionic villus sampling tests a tiny section of the placenta. The doctor will get this tissue using either a tube in your cervix or a needle through the stomach. CVS is conducted early in the pregnancy (between ten and thirteen weeks).  The test could cause side effects like bleeding, infection, or cramps.

When performing amniocentesis, the physician will put a needle through the stomach and in the sac, which surrounds the baby and take out a little amount of fluid. Then the laboratory will study the cells and proteins in the fluid. It is advisable to have a test between fifteen and twenty weeks. The test could cause infection, cramps, or bleeding.

Why most mothers prefer amniocentesis to CVS? You could request amniocentesis if you missed the first trimester time frame for chorionic villus sampling. Moreover, it has a lower risk of causing a miscarriage and can show neural tube birth defects (chorionic villus sampling cannot).

It is worth noting that if your physician recommends either of the diagnostic tests, it does not imply that your baby has a problem. Instead, it means the doctor is following up on your previous screening test or wants to be sure that everything is okay.

Genetic counseling can assist you in choosing the best diagnostic test. Your OBGYN will discuss both the advantages and disadvantages of the tests. It will also help decide on the best next steps to take if your results are positive.

Find a Renowned Obstetrician Near Me

You are likely to deliver a child with a chromosome abnormality if you are thirty-five years or older. Therefore, it is advisable to undergo genetic testing and screening as it will reduce anxiety. The tests will confirm or rule out if your baby has genetic defects like Down Syndrome and Trisomy 18. No matter the result, the Gyn LA medical team can work closely with you to develop a care plan designed to suit your medical history and personal needs. To book an appointment with one of our specialists in Los Angeles, call 310-375-8446 today.