From the moment a pregnancy is confirmed, the nine-month experience that follows is one of life’s most memorable events — a time when expectant mothers and soon-to-be fathers put the health of their unborn child at the top of their list of priorities.
 
Monitoring the unborn baby’s development and ensuring that all of its organs are functioning properly can be a source of significant anxiety for parents-to-be. The good news is, non-invasive prenatal testing (NIPT), which screens for chromosomal abnormalities in an unborn child, provides a new option to rule out the possibility of most genetic disorders, providing relief and peace of mind to couples awaiting the birth of a child. And in the rare event that an abnormality is found, NIPT testing can give parents the time they need to discuss all options with their doctor and make a considered decision.

What is NIPT Screening?

NIPT is a form of screening test aimed at identifying an unborn baby’s chromosomal abnormalities, which may be indicated by testing the blood of the mother. The test is capable of estimating a child’s risk of Down syndrome along with a number of other significant chromosomal disorders. The test can also determine the child’s gender from its sex chromosomes. Be sure to let your doctor know beforehand if you prefer not to know the baby’s gender.
 
Pregnant women can undergo NIPT screening from around the 10th week of pregnancy onwards. As the test is carried out on genetic material taken from a sample of the mother’s blood, NIPT is considered to be an extremely safe screening test. NIPT is capable of accuracy rates of up to 99% due to its reliance on next-generation sequencing for analyzing the presence of chromosomal irregularities. Test results are typically available in 5-14 days.
 
Humans typically have 23 pairs of chromosomes, or 46 chromosomes altogether (23 from the mother and 23 from the father). As a result, chromosomal abnormalities may take many forms; for instance, having one too many chromosomes (trisomy), having one too few chromosomes (monosomy), or lacking gene sections within chromosomes (microdeletion).

Age of the Mother

The most common causes of chromosomal abnormalities are associated with the mother’s increased age. For example, among the Down syndrome group of disorders, research shows that women aged 25 years have an approximately 1:1,100 chance, about 0.1%, of giving birth to a child with Down syndrome. This frequency changes to 1:350, about 0.3%, for women aged 35, while for women aged 40, the frequency increases further to 1:100, or about 1%.
 
Chromosomal abnormalities are known to be caused by a number of factors; some are related to the mother’s age, while others are tied to genetics, exposure to chemicals, or combination of these factors.
 

What Conditions Can NIPT Screening Identify?

 

• Down Syndrome / Trisomy 21

Down syndrome, also called trisomy 21, is the most common of all chromosomal abnormalities. The condition is caused by having an extra copy of the 21st chromosome. Infants born with this condition tend to have rather small and flat skulls with eyes set quite far apart. Their noses also tend to be flat and their ears are set lower, while their mouths tend to be smaller with a tongue that often protrudes out. The disorder can also involve heart defects, stunted development and a lower-than-average IQ.
 

• Edward’s Syndrome / Trisomy 18

Most cases of Edward’s syndrome, known as trisomy 18, result from having an extra 18th chromosome. Infants born with Edward’s syndrome tend to have smaller heads and jaws, while their ears are set lower than non-Edward’s infants. Edward’s syndrome may also result in a cleft palate as well as irregular finger and toe structures. Affected infants tend to suffer from heart and kidney defects, respiratory and digestive system disorders, and lower IQs. Children born with Edward’s syndrome usually do not survive beyond their first birthday.
 

• Patau Syndrome / Trisomy 13

Patau syndrome, called trisomy 13, results from having three copies of the 13th chromosome instead of the normal two. Infants born with Patau syndrome may have a cleft palate, small eyes, low ears and an excess number of fingers and toes. They are usually born deaf with neurological disabilities, rarely surviving beyond their first week.
 

• Sex Chromosome Aneuploidy and Fetal Sex Determination

Sex chromosome aneuploidy and fetal sex determination screening involves more than determining whether the unborn baby is a girl (XX) or a boy (XY); it also is used to identify an excess or deficiency of sex chromosomes (XO, XXX, XXY, XYY). Such screening enables medical staff to create comprehensive treatment plans based on the test results.
 

• Microdeletions

Screening for abnormalities resulting from a lack of some chromosome sections that are capable of causing DiGeorge syndrome, 1p36 deletion syndrome, Prader-Willi syndrome, Angelman syndrome, Cri-du-chat syndrome and Wolf-Hirschhorn syndrome.
 

• Genome-Wind Aneuploidy Detection

Screening for chromosomal abnormalities affecting those other than the 13th, 18^th, 21st pairs and sex chromosomes (19 pairs in total).

 

 

Screening Limitations

Some expectant mothers may be suffering from conditions that would prohibit them from undergoing NIPT screening. Your doctor will review any specific limitations that may apply in your individual situation when evaluating whether NIPT screening is right for you.