Pregnancy Testing


Choice in Genetic Testing in Your First and Second Trimesters

Pregnancy is a dynamic time. Several tests are available in your first and second trimesters to provide information about the genetic health of your developing baby.

Understanding Prenatal Genetic Testing Options

This video reviews and compares screening and testing options for Down syndrome and other chromosome abnormalities.


Noninvasive prenatal tests

Noninvasive prenatal tests (NIPT) can screen for trisomy 21 (Down syndrome) and other chromosomal abnormalities—as well as the sex of your baby—as early as nine weeks into your pregnancy, and with a high degree of accuracy. Labcorp offers three NIPTs.

Understanding Your MaterniT Results

This video explains what your MaterniT results mean and what next steps or other testing you might consider. 

Serum Screening

Maternal serum screening tests estimate the chance that your baby could have Down syndrome, trisomy 18 or open neural tube defects, leading to the detection of about 80% to 90% of babies with these birth defects, depending on the particular test your doctor uses and how far along you are in your pregnancy.

Similar to NIPT, a positive serum screen can be confirmed with a diagnostic test. As with NIPT, we offer choices.

Learn more about serum screening options

Pregnant woman doing exercise

Diagnostic Testing

Diagnostic procedures (such as amniocentesis and CVS, chorionic villus sampling) are used to test for chromosomal abnormalities, open neural tube defects, and/or specific inherited diseases.

We also offer pediatric diagnostic testing to analyze chromosomes in newborns and infants for changes that can explain certain birth defects or developmental delays.

Understanding Prenatal Microarray

This video explains the option of prenatal microarray testing and how it can provide valuable information about your baby's health. 

Understanding the difference

NIPT vs. Serum Screening vs. Diagnostic Tests

You may choose to have NIPT, a serum screening test, a diagnostic test, a combination of the tests, or no testing at all. Here are the most important differences between the tests:

  • NIPT

  • Can be performed as early as nine weeks
  • Tells you the chances of your baby having a chromosomal abnormality such as trisomy 21 (Down syndrome) and—depending on the type of NIPT you choose—many more conditions
  • Screens for fetal sex
  • Done via a maternal blood sample from the mother’s arm
  • Does not cause miscarriages
  • Can require diagnostic testing to confirm a positive result (a “positive result” likely means the baby is affected)
  • Serum Screening

  • Can be performed as early as 10 weeks
  • Done via a maternal blood sample from the mother’s arm
  • Does not cause miscarriages
  • Tells you the chance that your baby could have trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and when drawn after 15 weeks, open neural tube defects (such as spina bifida)
  • Sometimes show a high risk even when the baby does not have one of these problems
  • Diagnostic Tests

  • Can be performed as early as 10 weeks (CVS) or 15 weeks (amniocentesis)
  • Tell you with greater than 99% accuracy whether your baby is affected or is not affected with Down syndrome or trisomy 18
  • Tell you with greater than 90% accuracy whether your baby is affected with an open neural tube defect
  • Can test for other genetic disorders when additional risks are identified in a patient’s history
  • Are estimated to cause miscarriage in 1 in 300 to 1 in 500 pregnancies for amniocentesis and up to 1 in 100 with CVS
Couple talking with doctor

Carrier screening

While NIPTs, serum screening, and prenatal diagnostic testing indicate the genetic health of your baby, carrier screening is different, as it detects the carrier status of you and your partner, and helps to determine if there’s any risk of passing on a genetic disorder, such as cystic fibrosis (which affects about 1 in 3,500 babies born in the US).2 

These tests are performed on a blood sample from your arm, and can either be performed prior to or during a pregnancy.

Learn more about carrier screening tests.

Additional Resources


  1. Ob-Gyns release revised recommendations on screening and testing for genetic disorders [news release]. Washington, DC: American College of Obstetricians and Gynecologists (ACOG) and Society for Maternal-Fetal Medicine (SMFM); March 1, 2016. Accessed September 26, 2017.
  2. Cystic fibrosis and your baby. March of Dimes website. Accessed July 20, 2017.