Prenatal testing: Quick guide to common tests
Prenatal screening tests can provide information about your baby’s health before he or she is born. Consider the timing and what prenatal testing can reveal.
Prenatal testing is offered in all pregnancies. Here’s an overview of common prenatal screening tests:
|What it is||When it’s done||What the results might tell you||Follow-up|
|Cell-free DNA (cfDNA) screening|
|Blood test||As early as week 10||Risk of Down syndrome (trisomy 21), trisomy 18 and trisomy 13 and fetal sex||Possible invasive testing, such as chorionic villus sampling or amniocentesis|
|1st trimester screening|
|Blood test and ultrasound||11-14 weeks||Risk of Down syndrome (trisomy 21) and trisomy 18||Possible invasive testing, such as chorionic villus sampling or amniocentesis; cell-free DNA screening may also be considered|
|Blood test||15-22 weeks||Risk of Down syndrome (trisomy 21), trisomy 18 and open neural tube defects, such as spina bifida||Possible targeted ultrasound, or invasive testing such as chorionic villus sampling or amniocentesis; cell-free DNA screening may also be considered|
Some health care providers choose to combine the results of first trimester screening with the quad screen — although you won’t learn the final results of this sequential testing until both tests are completed and analyzed.
In addition, fetal ultrasound often plays an important role in prenatal care and screening. Early in pregnancy, ultrasound can be used to confirm and date a pregnancy. Later, ultrasound can be used to detect certain birth defects and fetal anomalies, including neural tube defects.
Blood tests and ultrasounds pose limited risks for you and your baby. If the results of a blood test or ultrasound are positive or worrisome, your health care provider might recommend a more invasive diagnostic test — such as chorionic villus sampling or amniocentesis. These tests can be used to diagnose conditions, but they carry a slight risk of pregnancy loss.
If you’re concerned about prenatal testing or wonder whether you need specific screening or diagnostic tests, discuss the risks and benefits with your health care provider.
Oct. 03, 2020
- Messerlian GM, et al. First trimester combined test and integrated tests for screening for Down syndrome and trisomy 18. https://www.uptodate.com/contents/search. Accessed Dec. 5, 2018.
- Frequently asked questions. Pregnancy FAQ133. Routine tests in pregnancy. American College of Obstetricians and Gynecologists. https://www.acog.org/Patients/FAQs/Routine-Tests-During-Pregnancy. Accessed Dec. 5, 2018.
- Messerlian GM, et al. Down syndrome: Overview of prenatal screening. https://www.uptodate.com/contents/search. Accessed Dec. 5, 2018.
- American College of Obstetricians and Gynecologists Committee on Practice Bulletins — Obstetrics, Committee on Genetics, and the Society for Maternal-Fetal Medicine. Practice Bulletin No. 163: Screening for fetal aneuploidy. Obstetrics & Gynecology. 2016;127:e123.
- AskMayoExpert. Prenatal screening: Types of screening tests. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2018.
- Frequently asked questions. Special procedures FAQ025. Ultrasound exams. American College of Obstetrics and Gynecology. https://www.acog.org/Patients/FAQs/Ultrasound-Exams. Accessed Dec. 5, 2018.