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Prenatal Genetic Screening Program

The BC Prenatal Genetic Screening Program oversees prenatal screening for Down syndrome, trisomy 18, and open neural tube defects across the province.

Prenatal genetic screening can tell a pregnant woman her chance of having a baby with Down syndrome, trisomy 18, or an open neural tube defect. It is offered free of charge as a choice to all pregnant women with MSP coverage in BC.*

For Health Care Providers

We ensure there is a centralized, coordinated system to guide prenatal genetic screening across the province, measure outcomes, evaluate and disseminate new evidence/knowledge, and provide educational and informational materials to women and health care providers. We have also improved prenatal screening by introducing newer screens with increased detection rates and fewer false positive rates.  

Current recommendations for screening and answers to frequently asked questions can be found in:

This section provides resources to assist health care providers in offering genetic screening in their medical practice. To navigate through this section, use the menu below (you can expand (+) or collapse (-) the menu as needed.

 

 

Non-Invasive Prenatal Testing (NIPT) is a relatively new non-invasive blood test that measures the amount of cell-free fetal DNA circulating in maternal serum. NIPT accurately measures the quantity variance of fetal and maternal chromosomal material and provides a screen risk for Down syndrome (trisomy 21), trisomy 18, and trisomy 13. The Down syndrome detection rate is >99% with a false positive rate of 0.1%. 


For more information, please review:

NIPT Funding

NIPT is funded for women who meet one of the following criteria:

  1. has received a Positive Screen result from IPS, SIPS, or Quad; 
  2. has had a previous trisomy 13, 18, or 21 pregnancy; or
  3. has a risk of Down syndrome greater than one in 300 based on results of screening and ultrasound marker(s) of aneuploidy.For more information, please visit our NIPT page.

 

Prenatal Diagnostic Testing on Amnios and CVS at BCW and RCH

Rapid aneuploidy detection (RAD) will be used as the first tier prenatal diagnostic test for all patients at BC Women's Hospital and Royal Columbian Hospital. Conventional cytogenetic karyotype analysis will be performed only when indicated. 


Review the Information Sheet for Ordering Physicians. 


There are no changes to cytogenetic test ordering at Victoria General Hospital.


Handling of Amniotic Fluid Samples at RCH

Effective March 31, 2016, the Molecular Cytogenetic Laboratory at Royal Columbian Hospital will discontinue chromosome analysis on amniotic fluid samples procured from women who are at low risk (i.e. AMA). This change complies with the SOGC-CCMG guidelines from 2011 (J Obstet Gynaecol Can 2011;33(9):955–960) and standardizes testing between RCH and C&W Cytogenetic/Molecular Laboratory. 


All amniotic fluid samples sent to RCH Molecular Cytogenetic Laboratory will have Rapid Aneuploidy Testing (RAD) in the form of Fluorescence in situ Hybridization (FISH). In 99% of cases, that result will be available within one business day. The FISH RAD testing done at RCH will rule out trisomy 13, 18, and 21 and sex chromosome aneuploidy. If the FISH testing is normal, then the sample will not be further studied. If the FISH test is abnormal or inconclusive, then the sample will be cultured, and standard chromosome analysis will be performed and that result reported out. Please send the routine two tubes of amniotic fluid (10 mL fluid/tube).


Standard chromosome analysis will continue to be performed if there is a parental history of a cytogenetically visible chromosomal anomaly or a history of a previous child with a chromosomally visible abnormality.


Pregnant women who are at high risk (i.e. ultrasound abnormality) and potentially will require microarray analysis should have the amniotic fluid sample sent to the C&W Cytogenetic/Molecular Laboratory for RAD and microarray testing.


 

Eligibility for IPS

Women who are ≥ 35 years old at their expected date of delivery (EDD) qualify for an NT ultrasound to be done in conjunction with first and second trimester serum markers (IPS).


In order to ensure the quality of an NT ultrasound, every sonographer must annually perform a minimum number. In order to maintain this minimum number in Northern Health and the East Kootenay/Kootenay/Boundary regions, pregnant women 30 years and older from these areas are eligible for an NT ultrasound as part of IPS.


The other eligibility criteria for NT to be done in conjunction with serum biochemistry (IPS) include:

  1. Women with twin pregnancies, regardless of maternal age.
  2. Women pregnant following invitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI).

Nuchal Translucency (NT) Sites in BC

View the locations and contact details for NT sites in BC


 

A detailed trimester ultrasound at 18-20 weeks is part of a woman’s prenatal standard of care in order to assess fetal anatomy and growth. An 18-20 week ultrasound without soft markers or anomalies can reduce the estimated risk of Trisomy 21 (Down syndrome) by approximately 50% (Smith-Bindman, 2007; from the PGSP Guideline newly revised April 2019). Soft markers or anomalies on an 18-20 week ultrasound increase the risk for aneuploidy and should be interpreted in conjunction with the prenatal screening (SIPS, IPS, or Quad) result. For more information, see Appendix 4 of the guideline for Prenatal Screening for Down Syndrome, Trisomy 18, and Open Neural Tube Defects .

Trisomy 21 Risk Calculator

 

 
 

It is a woman’s choice whether or not she wishes to have prenatal genetic screening. The following downloadable materials will help to educate your patients, so you can have an informed discussion with them and help them make a decision that is right for them.


Pamphlets

Prenatal Genetic Screening:
It’s Your Choice

A Screen Positive Result:
What does it mean and what do I do now?

Visual and Decision Aids

 

To order the Prenatal Screening Guideline, laminated reference cards, and patient information pamphlets please visit:

Order Form‎
 

 

IPS/SIPS or Quad

The Prenatal Biochemistry Laboratory at BC Children's and BC Women's performs the serum biochemistry testing and the reporting of SIPS, IPS and Quad screen results.

Lab Requisition Form for Ordering IPS/SIPS or Quad

Current Version - The lab requisition was updated (in June 2017) to reflect that the Part 2 (or Quad) serum collection can now be done earlier, starting at week 14. Part 2 blood can be now collected from 14+0 - 20+6 weeks. For optimal but still early results, women should aim to have their Part 2 blood collected from 15+0 -16+0 weeks. A risk calculation for Down syndrome and open neural tube defect can then be reported as early as 16-17 weeks, which provides additional decision-making time if more testing is warranted (such as NIPT or Amnio). 


Print out a lab requisition and fill it out manually, or download an interactive lab requisition to fill out on the computer and then print out.


Give the completed requisition(s) to your patient to accompany their blood sample to the laboratory. Each blood sample must be accompanied by a completed requisition.


Lab Reports for IPS/SIPS or Quad

View a sample prenatal screen report.
 
The report shows screen negative and screen positive results for Down syndrome and open neural tube defects. The report does not display results for trisomy 18 unless the result is screen positive. Note - if Part 2 serum is collected in week 14, MS-AFP is used to assess for ONTD as usual but an ONTD risk calculation will not be shown on the report; instead, comments will appear to indicate whether its negative or positive.
 
Screen positive results are called out to the ordering health care provider by genetic counsellors in the Prenatal Biochemistry Laboratory as soon as results are known.

Reports are faxed to the ordering health care provider and to the “copy to” providers listed on the requisition. Hard copies will not be mailed.

 
Patient Counseling
For additional patient counseling regarding prenatal screening and/or family history, please contact Medical Genetics:

Vancouver
Prenatal Referral Centre
Provincial Medical Genetics Program
BC Women's Hospital & Health Centre

Phone: 604-875-2818
Fax: 604-875-3484

Referral Form (print, then fill out manually) or  Fillable Referral Form (download, fill out on the computer, then print).

Victoria
Department of Medical Genetics
Victoria General Hospital

Phone: 250-727-4461
Fax: 250-727-4295


Referrals
Patients must be referred to Medical Genetics by their health care provider. Both Medical Genetics departments offer face-to-face counselling and possibly (but limited) telehealth counselling for those unable to travel. Telephone counselling is possible if telehealth is not available.

To ensure timely processing of referrals, please fax the completed referral form and all available records to the appropriate Medical Genetics clinic:

  • any prenatal screen results (ie. NT, Quad/SIPS/IPS, first trimester screen)
  • all obstetrical ultrasounds done in this pregnancy
  • antenatal record part 1 & 2
  • blood type report from Canadian Blood Services
  • hematology panel, any thalassemia investigations
  • any relevant consultations and other reports 
 
The Genome Canada / UBC Pegasus NIPT research study is no longer recruiting pregnant women for the low-risk part of the study. 

However, the study is still looking for women who meet the criteria for the high-risk part of the study. 

The high-risk criteria are: 

  • 19 years or older
  • pregnant with a singleton
  • between 10 weeks and 23 weeks 6 days gestation
  • qualifies for invasive procedures (amniocentesis/ CVS) whether you choose them or not (applicable invasive procedure eligibility is: screen positive for trisomy 21, 18; maternal age 40 years or older; a previous trisomy pregnancy; or pregnancy with IVF with ICSI) 
If you meet the above criteria and would like to donate a blood sample to help validate NIPT technology in Canada, please contact the study coordinator at kharrington@cw.bc.ca.  

Please note that study participants do not receive any results. 


 
For Families
If you are thinking of having a baby, or if you are pregnant, this section on prenatal genetic screening can answer many of your questions. It can also prepare you for an informed discussion with your partner and your health care provider.

It's your choice whether or not to have prenatal genetic screening. The earlier in your pregnancy you see your health care provider, the more options you will have. 

Please watch this video for more information about the screening options available to you. 

 Content Editor ‭[3]‬
Learn More

To learn more about prenatal genetic screening in BC:


When to Have Blood Drawn

If you have decided to have prenatal screening, use our pregnancy dating tool to find out when to have your blood drawn.


*If you do not have MSP coverage, prenatal genetic screening is available for a fee. BC Children's Hospital finance department will send you an invoice for $150. You may also be charged for blood collection by the facility who draws your blood.

 
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SOURCE: Prenatal Genetic Screening Program ( )
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