Ultrasound screening can be a valuable component of your prenatal care in the way it examines your baby for physical differences, but there are still limitations to what prenatal ultrasounds can detect. During pregnancy, your healthcare provider may offer or recommend different blood screening tests to complement the information you’ll gather from ultrasound screening. Blood screening tests usually will analyze different hormones, proteins, or pieces of genetic material in order to assess your pregnancy’s chance for certain health conditions which may not be visible on ultrasound. 

Non-invasive prenatal screening tests

Non-invasive prenatal screening tests are blood tests that a pregnant person can take to check the pregnancy for certain chromosomal conditions, such as trisomy 21, 18, and 13. Non-invasive prenatal screening (NIPS), also called non-invasive prenatal testing (NIPT), can be performed as early as 9 weeks gestation, and unlike other prenatal blood screens, they generally do not have a maximum gestational age. NIPS or NIPT typically involves a simple blood collection from the pregnant person, and there’s no associated risk to the pregnancy. Results from NIPS/NIPT usually are available within one to two weeks, and will indicate whether there is an increased chance of certain chromosome conditions in the pregnancy.

The American College of OB/GYNs recommends that all pregnant patients have the option to undergo NIPS/NIPT. Although this screening is not diagnostic, and it’s possible to have false positive or false negative results, research in pregnancies of all risks has demonstrated NIPS to be more accurate than other prenatal blood screens.

Combined first-trimester screening

Combined first-trimester screening has two essential components: the nuchal translucency (NT) sonogram at 11w0d-13w6d, and a maternal blood sample collection performed within this same window. Data from the NT sonogram and the blood sample are analyzed to provide an adjusted risk for Down syndrome (trisomy 21) and Edwards syndrome (trisomy 18); sometimes, a combined risk for Edwards syndrome and Patau syndrome (trisomy 13) will be provided. Since both the NT sonogram and the maternal blood sample collection are technically non-invasive, there are no linked risks for pregnancy loss from combined first-trimester screening. While this screening does not perform as well as NIPS/NIPT for identifying certain chromosome conditions, it may be a good option for parents whose insurance does not cover NIPS/NIPT without a “high risk” indication.

Serum Integrated Screening

Serum integrated screening, or integrated screening for short, analyzes chemicals from a first-trimester maternal blood sample and a second-trimester maternal blood sample. It provides an adjusted risk for Down syndrome, trisomy 18, and spina bifida once both blood samples have been collected and analyzed. Since serum integrated screening does not involve an ultrasound, it may be preferred by your prenatal care provider if an NT-certified sonographer is not available in your area. Still, the performance of NIPS/NIPT for detecting fetal chromosome conditions is much higher than that of serum integrated screening, and NIPS/NIPT also does not require a prenatal ultrasound to be performed.

Quad Screening (Quad Marker Test) 

Another type of prenatal screening test is the quad screen, or quadruple screen test, which may be offered during the second trimester of pregnancy. This blood test checks for specific hormones produced by the baby and the placenta and can indicate a higher chance of certain congenital conditions, such as Down syndrome. The quad screen is typically done between 16 and 18 weeks of pregnancy, and results tend to be available within one to two weeks

Prenatal screening tests vs. prenatal diagnostic tests 

Amniocentesis and chorionic villus sampling (CVS) are two types of prenatal screening tests that analyze samples directly from the pregnancy  – an amniotic fluid sample for amniocentesis, and tiny pieces of placental tissue for CVS. A trained physician (usually a high-risk OB/GYN called a Maternal Fetal Medicine specialist) performs amniocentesis by inserting a needle into the uterus to collect a few tablespoons of amniotic fluid containing genetic material from the baby’s cells. Amniocentesis is performed under ultrasound guidance so that the physician is able to collect the amniotic fluid sample from the largest fluid pocket, as far away from the baby as possible. This procedure is usually only performed after around 16 weeks gestation, when the membranous layers of the gestational sac have fused together.

In contrast, a MFM specialist usually performs a CVS procedure between around 10 to 14 weeks gestation, and does this by taking a very small biopsy of the placenta. This biopsy can be completed either through a transabdominal approach or a transvaginal approach, depending on factors such as the location of the placenta’s attachment to the uterus.

Although both the amniocentesis and CVS procedures are considered safe when performed by an experienced provider, these procedures do carry some risks for pregnancy loss, such as if the bag of water were to break or an infection were to occur after the procedure. It’s always important to talk to your provider about the risks and benefits of prenatal diagnostic procedures like amniocentesis and CVS so you can make an informed choice.

Some parents choose to begin their prenatal screening and testing journey with non-invasive prenatal screening tests, such as NIPS, knowing they can follow up with prenatal diagnostic testing if NIPS reveals an abnormal or high-risk result. In other instances, parents may prefer to schedule prenatal diagnostics testing as their first-tier approach for gathering health information about their baby. If you’re not sure what approach is right for you, you might benefit from consulting with a genetic counselor about your pregnancy and family history, any other risk factors you perceive, and each of your options for prenatal screening and testing. 

Where to get more information?

As a Juno patient, you’ll have access to genetic counseling services. Our genetic counselors can help better inform your screening decisions or review your results and any concerns from the comfort of your home - just call or click to set up a consultation. Whether you are still deciding if the NIPS is right for you or if you want to discuss what your results mean for your specific situation, Juno will be with you every step of the way. 

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Please be aware: JunoDx.com and the materials and information it contains are not intended to be and do not constitute medical advice, other health advice, or diagnosis.  Do not use JunoDx.com or the materials and information published at JunoDx.com as a substitute for medical care and treatment. You should always consult with a qualified physician or healthcare provider about your specific circumstances.