Non-invasive Prenatal Testing

During a pregnancy, there are small pieces of genetic material (known as DNA) from the placenta that can be found in the bloodstream.

Non-invasive prenatal testing (NIPT) is a very accurate form of prenatal screening that looks at this DNA and can tell what the chances are that a baby has one of the conditions screened.

Non-invasive prenatal testing

It is important to remember that NIPT is a screening test and will not give a definite answer about any of the conditions.

Conditions screened

NIPT that is covered by the Ontario Health Insurance Plan (OHIP) will screen pregnancy for:

trisomy 21 (Down syndrome)
trisomy 18
trisomy 13

Discuss with your health care provider whether you would like to use NIPT to screen your pregnancy for the fetal sex and any differences in the sex chromosomes (called sex chromosome aneuploidy).

If you choose to pay for NIPT, discuss with your health care provider whether you would like to screen for any of the additional conditions that these companies offer.

Additional conditions screened

Some of the NIPT labs are able to use this bloodwork to screen pregnancies for other genetic conditions, specifically microdeletion syndromes. It is important to know that these conditions are rare in the general population and happen when there are missing pieces of chromosomes (ie. deletions). The chances of a baby having one of these conditions is not related to maternal age (or the age of the egg donor).

At this time, the current provincial guidelines do not support the use of NIPT to screen for microdeletions.

Benefits of NIPT

Accuracy: NIPT is a very accurate screening test for trisomies 21, 18 and 13. It is more accurate than conventional screening (eFTS and MSS), detecting more than 99% of pregnancies where the baby has trisomy 21.

Timing: NIPT can be done as early as 9 weeks of pregnancy and results are typically reported within 7-10 days.

No risk: Because NIPT is a simple blood test, it poses no risk to pregnancy.

Limitations of NIPT

Not diagnostic: NIPT is a very good screening test but it cannot give a definite “yes” or “no” answer. Only invasive diagnostic testing (e.g. chorionic villus sampling or amniocentesis) can do that.

Incidental findings: Some of the DNA in the NIPT blood sample is from the mother (or donor) and this means that the test is also looking at maternal DNA, not just the baby's. In rare cases, NIPT may identify a genetic difference in the maternal (or the donor) DNA. This type of result should be further reviewed with a genetic counsellor who can discuss options for further testing.

When NIPT cannot be done

NIPT may not be available if:

there is a vanishing twin – ongoing pregnancy that started as a multiple pregnancy with subsequent miscarriage of one or more baby
there are more than two babies (triplets, quadruplets, etc.)

How the funding for NIPT works

NIPT is available to all pregnant individuals in Ontario but will only be covered by OHIP if specific criteria are met.

For patients that do not meet the requirements, NIPT can be paid for out of pocket. The cost varies between the labs and health care providers will need to complete the appropriate self-pay requisition (lab-specific) for testing.

OHIP will fund NIPT if:

Category I criteria (can be ordered by any physician)

a positive prenatal screening result from multiple marker screening (MMS) for this pregnancy
the maternal age (or age of the egg donor) will be 40 years or older at the expected date of delivery
- in the context of in vitro fertilization, maternal age is defined by the age of the egg donor (patient or donor)
the nuchal translucency (NT) measurement is ≥3.5mm
there is a personal history of a previous pregnancy or child with a specific chromosome condition

If you meet one of these requirements, your health care provider can use the OHIP-funded requisition for testing.

Category II criteria (must be ordered by a genetics or maternal-fetal medicine specialist)

there are findings on ultrasound which are associated with an increased chance for trisomy 21, trisomy 18 or trisomy 13
there is risk for a sex-linked genetic condition
it is a twin pregnancy and maternal age (or the age of the egg donor) will be over the age of 35 at the expected date of delivery
the ultrasound shows findings suggestive of a sex chromosome difference
the ultrasound shows findings suggestive of a disorder of sex determination