Prenatal Screening


There are multiple options for prenatal screening, depending on your age and personal and family history. If you choose to do prenatal screening we will work with you to decide which is your most appropriate option. Some choose to have it while others do not. We’ll talk to you about it and help you decide.

IPS (Integrated Prenatal Screening)

The IPS uses an ultrasound and various measurements of genetic abnormalities to test for the possible presence of Trisomy 21 (Down syndrome), Trisomy 18 (Edwards syndrome), and open neural tube defects (NTD), including anencephaly and spina bifida. It comprises the following steps:

  • An ultrasound and blood work between 10 and 14 weeks
  • A second blood test at around 15 and a half weeks (the ultrasound technician will give you the exact date after doing measurements during the 10-14 week ultrasound)
  • Results are available after the second blood test when they are integrated with the 10-14 week results to give you a risk ratio (this is where the “integrated” part comes in). These integrated results will give you the probability of your baby having one of the tested conditions.

NIPT (Non-Invasive Prenatal Screening)

This new test is a single blood test done at 9+weeks to look for the possible presence of Trisomy 13, 18, 21 (Down syndrome), Triploidy and Monosomy X. You can also request screening for 22q11.2 deletion, 1p36 deletion, Angelman, Cri-du-chat and Prader-Willi Syndrome. It will also tell you the sex of the baby if you wish.

The test uses fetal DNA found the mother’s blood (meaning it only requires a blood draw for mom). It is more accurate than IPS but still only a screening test. It is covered by OHIP for certain women (see link for criteria below) or can be done privately if you wish to pay for it. It does not screen for NTD so you still need to do an additional blood test at 15-16 weeks.


This is offered automatically to women over 40 years old and certain others, as well as if you have a positive IPS or NIPT test. We can tell you more about this if it applies to you. 

We call you with the results of all these tests. Please call, however, if you do not hear from us by 1- 2 weeks after your test.

More information is available from the Children’s Hospital of Eastern Ontario (CHEO):

Frequently asked questions: Prenatal Screening

A guide to understanding prenatal screening tests