At MomDoc, our goal is to empower you with knowledge so you can make the most informed choices for your growing family. Early in your pregnancy, you will be offered several optional genetic tests designed to assess the risk of certain chromosomal abnormalities or genetic disorders in your baby.
It is important to understand that these tests are strictly optional. Choosing to proceed with genetic screening is a personal decision, and there is no right or wrong answer. Your care team is here to walk you through the options, outline what each test looks for, and answer any questions you may have.
Maternal Carrier Screening
Unlike other tests that check the fetus, this genetic blood test evaluates your DNA. Its purpose is to determine if you are a healthy carrier for specific recessive genetic mutations that could potentially be passed on to your child.
This screening typically looks for conditions such as Cystic Fibrosis, Hemoglobinopathies (like Sickle Cell trait), and Spinal Muscular Atrophy (SMA).
- If you test negative: Your risk of passing these specific conditions to your baby is extremely low.
- If you test positive: It does not mean your baby has the disorder. It simply means your partner (the father of the baby) should also be screened. If both parents are carriers of the same recessive gene, there is a 25% chance the baby will inherit the condition.
Non-Invasive Prenatal Testing (NIPT)
The NIPT is a highly accurate, simple maternal blood test that can be performed any time after 10 weeks of pregnancy.
During pregnancy, small fragments of the baby's DNA cross the placenta and circulate in the mother's bloodstream. The NIPT isolates this cell-free DNA to assess the risk of the three most common fetal chromosomal abnormalities (trisomies):
- Trisomy 21 (Down syndrome)
- Trisomy 18 (Edwards syndrome)
- Trisomy 13 (Patau syndrome)
Because it evaluates fetal DNA, the NIPT is approximately 99% accurate at detecting these trisomies. As an added benefit, this test also gives you the option to discover the sex of your baby very early in your pregnancy.
Ultrascreen (First Trimester Screening)
Performed between 11 and 14 weeks, the Ultrascreen combines two modalities: a maternal blood draw and a specialized ultrasound.
The ultrasound carefully measures the clear space at the back of the developing baby's neck (the nuchal translucency). When combined with the blood work, this screening assesses the risk for the same three trisomies as the NIPT, while also evaluating for structural anomalies. It has approximately a 91% detection rate. Unlike the NIPT, the Ultrascreen cannot determine the sex of the baby.
Alpha-Fetoprotein (AFP) Screening
Performed later in your pregnancy, between 15 and 21 weeks, the AFP is a maternal blood test that specifically screens for neural tube defects.
These are defects of the developing brain and spine, such as Spina Bifida and Anencephaly. Because the earlier NIPT and Ultrascreen do not evaluate for neural tube defects, the AFP blood test is often recommended as a complementary screening in your second trimester.
The Quad Screen
Also performed between 15 and 21 weeks, the Quad Screen is a maternal blood test that evaluates four specific proteins and hormones in your blood.
It functions similarly to the earlier screenings, checking for Trisomy 21 and including the AFP measurement for neural tube defects. However, compared to the NIPT, the Quad Screen generally has a higher rate of false-positive results. Your provider can help you decide if a Quad Screen is beneficial based on your previously completed testing.
Next Steps: Screening vs. Diagnostic Testing
It is critical to remember that all the options listed above are screening tests. They evaluate risk, but they cannot provide a definitive diagnosis.
If any of your screenings return a positive or "high-risk" result, your MomDoc provider will sensitively guide you through the next steps. A true diagnostic test, such as Chorionic Villus Sampling (CVS) or an Amniocentesis, may be indicated to confirm the result. Because these procedures carry a slight risk to the pregnancy, they are not performed at our standard MomDoc clinics; instead, we will immediately refer and coordinate your care with a trusted high-risk Maternal-Fetal Medicine (MFM) specialist.