Prenatal Tests And Screening For Birth Defects

Posted On: January 19, 2022 By CIW

If you’re pregnant or planning to become pregnant, it’s vital to have various prenatal tests and screenings performed for a number of reasons. These routine exams help your pregnancy care team monitor the health of both you and your baby, as well as identify certain conditions that could affect the delivery plan for your child. Some of these tests are done multiple times throughout pregnancy and others are done only in certain conditions. At Carnegie Imaging for Women, we provide essential ultrasound screenings and other scans to make sure you have a safe and healthy delivery.

What do Prenatal Tests Screen For?

During regular pregnancy checkups, you’ll have various screenings and diagnostic tests performed to check on the development of your baby, make sure both you and the baby are healthy, and identify risk factors for genetic abnormalities.

Primarily, these maternal screenings will identify pregnancies at higher risk of a genetic abnormality while prenatal ultrasound will look at the developing baby and identify any physical issues, such as birth defects and growth problems. Birth defects are health conditions that are present at birth, resulting in a change or loss of function of various parts of the body, which can affect how your baby develops or is born. Genetic conditions are often the result of chromosomal abnormalities, perhaps the most well-known one being Down syndrome, which is caused by having three copies of chromosome 21 instead of only two.

Genetic conditions are sometimes passed down through families, meaning a family history is also a good way of assessing your baby’s risk factor for certain conditions, including cystic fibrosis, sickle cell disease, and various heart problems.

Types of Prenatal Tests

As mentioned, you’ll have many checkups and screenings throughout pregnancy, some of which are best performed early and others later in development. Although every case is unique, here’s a general overview of what to expect from screenings and testing during each trimester.

First Trimester

Many genetic tests and screenings are available during the earliest part of your pregnancy once you find out you’re pregnant. These include carrier screenings for genetic mutations that you may carry as a mother, which would indicate a risk factor for your baby, particularly if your spouse is also a carry of the same mutation. Depending on the results of this test, whether taken through a blood or saliva sample, further testing may be required.

Another possible test for genetic conditions is cell-free DNA (cfDNA) testing, which is also known as non-invasive prenatal screening. This test analyzes free-floating DNA (that’s not encased in a cell) of both you and your baby’s genetic material to identify potential chromosomal abnormalities.

Finally, ultrasound imaging is commonly performed to date your pregnancy, see whether there is more than one fetus or placenta, and check on your baby’s heart.  Additionally, your doctor may recommend a nuchal translucency screen which is an ultrasound screening test to identify if your pregnancy is at risk for chromosome and/or genetic abnormality.   It also allows for the first evaluation of any birth defects on the baby.

If a screening test returns as high risk for a genetic condition and/or nuchal translucency ultrasound appeared abnormality patients have the opportunity for diagnostic invasive testing via chorionic villus sampling (i.e. CVS), where a small amount of the placenta is sampled and the genetics evaluated.   Patients may also opt to have CVS testing if they desire definitive testing of the genetics of the pregnancy regardless of screening test results.

Second Trimester

Ultrasound imaging will continue to play a role in the second trimester, as well as other additional screenings. The most important ultrasound in the second trimester is the detailed anatomy surveillance which is a detailed look at all the structure on the baby to identify whether there is a major and/or minor birth defect on the baby.  This ultrasound is commonly performed between 20 to 22 weeks; however, your provider may request an early “look” anatomy between 16 to 18 weeks.  Additionally, you can have a blood drawn for further chromosome abnormality and/or open neural tube defects screening to further understand the risk factors for genetic and other conditions.   Depending on your history, a screening fetal echocardiogram where a detailed ultrasound look of the baby’s heart development may be performed in the second trimester.

In addition, diagnostic invasive testing via amniocentesis can be performed to help confirm a potential condition.

Third Trimester

As you prepare to deliver the baby, by this point we will have performed most if not all the tests we need to in order to determine the best plan for delivery and help provide expectations for your baby’s health both in the early years as well as long-term care needs.  In the third trimester, you provider may send you for ultrasounds to ensure adequate growth and amniotic fluid for the baby.

Pregnancy Care and Testing in New York City

With the tools and technology available at Carnegie Imaging for Women, we provide comprehensive care for expectant mothers to ensure you have the information and services you need to deliver a happy, healthy baby. To learn more or schedule your first appointment, don’t hesitate to call one of our two office locations or contact us online today.

Carnegie Imaging for Women blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!

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