The birth of every new life is to be celebrated. During the first trimester of pregnancy, doctors from the department of gynecology and obstetrics may suggest pregnant mothers undertake noninvasive prenatal testing (NIPT) to screen whether the baby might face increased risk due to chromosomal abnormalities.

During pregnancy, some of the baby’s DNA passes into the mother's bloodstream. NIPT analyses the genetic information contained in this DNA to screen whether your baby is at increased risk of:

- Down syndrome (trisomy 21)
- Edwards syndrome (trisomy 18)
- Patau syndrome (trisomy 13)

Chromosomal abnormalities screening with NIPT

For example, Down syndrome, often presents moderate to severe intellectual disability and physical developmental abnormalities and has an incidence of about 1 in 800 to 1 in 1000, which increases significantly with maternal age.

Possibility of Down syndrome with maternal age; Source: Diagnostics (Basel), 2013 May 31; 3(2) 291-314

Timely and comprehensive prenatal screening not only helps parents to better understand the health status of the mother and baby, but also helps expectant parents detect abnormalities early and plan for treatment in consultation with doctors from the department of gynecology and obstetrics.

Traditional Down syndrome screening is mainly done through biochemical markers, which is usually performed between the 11th and 19th week of pregnancy and has an estimated 88 percent detection rate. However, next-generation sequencing based (NGS-based) NIPT can be performed as early as the 10th week, while raising the detection rate of Down syndrome to an estimated 99 percent detection rate. 

Comparison of serological test versus NIPT

With NIPT, invasive testing can be minimized, and false negatives are significantly reduced. Therefore, NIPT is widely recommended by authoritative organizations in this field, such as the American College of Medical Genetics and Genomics (ACMG) and the American College of Obstetricians and Gynecologists (ACOG), for the screening of many chromosomal abnormalities.

With the guidance of their doctors, NIPT is suitable for pregnant women, such as singleton and twin pregnancy, and pregnancies with a history of trisomy, high risk of aneuploidy (having missing or extra chromosomes), contraindications for invasive procedures, or in-vitro fertilization.

NIPT consists of the following steps: 5-10ml of blood of the pregnant woman at 10-24 weeks is drawn and sent for testing under the advice and guidance of doctors from the department of gynecology and obstetrics; the laboratory conducts a DNA test on the blood samples; and the pregnant woman obtains the NIPT report.

It's important to be aware that NIPT is a screening tool, not a diagnostic test. This means it can't diagnose a genetic condition; it may only predict your baby's related risk. If the NIPT report indicates a high risk, the pregnant woman should undergo prenatal diagnosis as advised by doctors from the department of gynecology and obstetrics.

Additional Reading

Nutrition and Prenatal Tests are Vital for Future Parents l BGI Perspectives

How the latest treatments and prenatal tests help with infertility problems l BGI Perspectives

Whole Genome Sequencing is a more comprehensive Prenatal Test  l BGI Perspectives

About NIFTY®: Non-invasive prenatal testing

Learn more about the NIFTY® Test - the world's leading non-invasive prenatal test (NIPT). Over 10,000,000 NIFTY samples processed as of 2021.

About BGI Genomics

BGI Genomics, headquartered in Shenzhen China, is the world’s leading integrated solutions provider of precision medicine. Our services cover more than 100 countries and regions, involving more than 2,300 medical institutions. In July of 2017, as a subsidiary of BGI Group, BGI Genomics (300676.SZ) was officially listed on the Shenzhen Stock Exchange.