Chromosome Screening

Prenatal screening can tell you the chance for having a baby with certain chromosome differences. The conditions formally screened for in Ontario are trisomy 21 (Down syndrome) and trisomy 18 (Edwards syndrome). Some of the screening options below may also screen for other chromosome differences, including trisomy 13 (Patau syndrome) and sex chromosome differences.

For health-care providers

Requisitions

Find requisitions for Multiple Marker Screening (MMS) and Non-Invasive Prenatal Testing (NIPT) here.

What are Chromosome Conditions?

Chromosome conditions are caused by having extra or missing chromosomes. These differences can affect a baby’s development, learning, and health in different ways, and the impact can vary widely from person to person.

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Enhanced First Trimester Screening (eFTS)

You can get publicly-funded Enhanced First Trimester Screening (eFTS) in the first trimester of pregnancy.

Second Trimester Screening (STS)

You can get publicly-funded Second Trimester Screening (STS) in the second trimester of pregnancy.

Non-Invasive Prenatal Testing (NIPT)

Non-invasive Prenatal Testing (NIPT) is the most accurate prenatal genetic screening test and may be publicly-funded or private-pay depending on your situation.

Nuchal Translucency (NT) Ultrasound

The 11-14 week (nuchal translucency) ultrasound can be done as part of enhanced First Trimester Screening or on its own.

18-22 week Detailed Anatomy Ultrasound

You can have the 18-22 week ultrasound no matter what prenatal genetic screening choice you make.

Screening for twins or more than two babies

Read about the screening options available to individuals expecting twins or more than two babies.

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Screening for vanishing twins

If your pregnancy started as a twin pregnancy and one twin miscarried, this is sometimes called a "vanishing" twin pregnancy. Read about screening options available.

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For Health-Care Providers

Office Guide to Prenatal Screening Options for Chromosome Differences

See Resource

For Health-Care Providers

How to Offer Prenatal Screening for Chromosome Differences

See Resource

Prenatal Screening Ontario
CHEO Research Institute
Centre for Practice-Changing Research Building
401 Smyth Road
Ottawa, ON K1H 8L1

pso@bornontario.ca

Information line
Phone: 613-737-2281
Toll-Free: 1-833-351-6490

Monday to Friday, 9:00 AM to 3:00 PM EST