Provider Tools
Point of Care Tools
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Are you looking for ways to start the conversation with your patient about prenatal screening?
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Are there questions that you can ask to help support an informed decision?
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What are the next steps when your patient receives a positive result?
Our point of care tools were created to help inform the conversation about prenatal screening and to support primary care providers and patients through these decisions.
Patient Leaflets
Counselling Tips for Providers
- How to Offer Prenatal Screening
- How To Discuss Prenatal Screening Results - Traditional Screening (eFTS/MSS)
- How To Discuss Prenatal Screening Results - Non-invasive Prenatal Testing (NIPT)
Other Provider Tools
We continue to develop additional patient and provider tools. Please continue to check our site for updated and newly created resources.
Are you are looking for further tips and information on how to counsel positive or negative screen results? Or more information on what to offer your prenatal patients? Our genetic counsellors can be reached Mon-Fri 8am-4pm at (833)351-6490 or pso@bornontario.ca
Prenatal Screening Performance
Chromosome Difference | eFTS % (95% CI) | MSS (1 in 200)% (95% CI) | MSS (1 in 350)% (95% CI) | |
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Sensitivity (Detection Rate) |
Trisomy 21 |
88.82 (84.98, 91.97) |
80.56 (63.98, 91.81) |
92.31 (74.87, 99.05) |
Sensitivity
(Detection Rate) |
Trisomy 18 |
78.22 (68.90, 85.82) |
60.00 (14.66, 94.73) |
66.67 (9.43, 99.16) |
False Positive Rate | Trisomy 21 |
6.65 (6.51, 6.79) |
5.08 (4.74, 5.42) |
7.75 (7.32, 8.20) |
False Positive Rate | Trisomy 18 |
0.23 (0.21, 0.26) |
0.50 (0.40, 0.62) |
0.92 (0.77, 1.09) |
Notes
- Singleton pregnancies with an EDD of 01-Sep-2016 to 31-Mar-2019 were include to calculate the screening performance.
- "eFTS" includes both 4-marker and 5-marker eFTS.
- MSS performance was calculated using the standard screening cut-off of 1 in 200, as well as the 1:350 cut-off that was implemented in response to the COVID-19 pandemic.
- Uninterpretable, inconclusive, mosaic and partial cytogenetic results were excluded from this cohort.
- Outcome data for autosomes screened (chromosomes 21 and 18) were supplemented using data from the BORN information system (BIS) for negative results only, where the outcomes for pregnancies with no cytogenetic outcome were set to test-negative when their corresponding BIS record had no indication for the disorder during the perinatal period.
Chromosome Difference | Sensitivity (Detection Rate)% (95% CI) | False Positive Rate% (95% CI) | Positive Predictive Value % (95% CI) |
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Trisomy 21 |
99.80 (98.97, 99.99) |
0.11 (0.08, 0.16) |
93.33 (90.85, 95.31) |
Trisomy 18 |
94.92 (89.26, 98.11) |
0.04 (0.02, 0.07) |
90.32 (83.71, 94.90) |
Trisomy 13 |
88.24 (72.55, 96.70) |
0.04 (0.02, 0.07) |
68.18 (52.42, 81.39) |
Notes
- Singleton pregnancies with an EDD of 01-Sep-2016 to 31-Mar-2019 were include to calculate the screening performance.
- No-call and missing data screening results were excluded from this analysis.
- Uninterpretable, inconclusive, mosaic and partial cytogenetic results were excluded from this cohort.
- Outcome data for autosomes screened (chromosomes 21, 18, and 13) were supplemented using data from the BORN information system (BIS) for negative results only, where the outcomes for pregnancies with no cytogenetic outcome were set to test-negative when their corresponding BIS record had no indication for the disorder during the perinatal period.
- Positive predictive value: probability that subjects with a "high risk" screening result have the chromosome difference. A "high risk" result in a high risk population (e.g. screen positive eFTS, ultrasound abnormalities) is more likely to be a true result than a "high risk" screening result in a low risk population.
When to Consider Referral to a Genetics Centre
- NT measurement is increased (3.5 mm or above)
- NIPT result is “high risk”, the NIPT fails or there is an unusual NIPT result
- Ultrasound anomalies or certain soft signs
- Personal or family history of genetic conditions, intellectual disabilities or birth defects which may impact the pregnancy
- Recurrent miscarriages
- Pregnant individual is considering invasive testing
Genetic clinics vary in their referral criteria. You may consider contacting your local genetics centre to obtain more centre-specific guidance.
Additional Resources
MedlinePlus |
The Society of Obstetricians and Gynecologists of Canada |
Genetics Education Canada-Knowledge Organization |
Centre for Effective Practice |
Canadian Association of Genetic Counsellors |
List of contact and referral information for Canadian genetic clinics |
Best Start/Health Nexus |
The Best Start Resource Centre supports service providers who work in preconception health, prenatal health and early child development |
Down Syndrome Association of Ontario |
DSAO is a charitable, non-profit organization composed of local Down syndrome associations from across the province of Ontario |
Canadian Down Syndrome Society |
More information about Down syndrome with links to local parent support groups on the Canadian Down Syndrome Society website. |
S.O.F.T. Support Organization for Trisomy 13, 13 and Related Disorders |
Spina Bifida and Hydrocephalus Association of Canada |
Spina Bifida and Hydrocephalus Association of Canada website |
Pregnancy and Infant Loss (PAIL) Network |
The Pregnancy and Infant Loss Network provides support to families across Ontario who experienced the loss of a pregnancy or infant. |