Pregnant woman

Important Prenatal Screening Service Announcement - Information for Health Care Providers

Update (January 12, 2021) - The temporary measures outlined below came into effect on April 6, 2020 and have been extended to June 30, 2021. 


Ontario currently uses a two-step prenatal screening system, with enhanced First Trimester Screening (eFTS) generally being the first step. However, at the onset of the COVID-19 pandemic, the delivery of prenatal screening services in Ontario was impacted:

  • Some diagnostic imaging centres were not offering dating and NT ultrasounds
  • Community blood collection services were being consolidated to a smaller number of labs 
  • Pregnant individuals in self-isolation were missing the NT ultrasound window 

Temporary changes were recommended by PSO and endorsed by the Ontario Ministry of Health on April 6, 2020 to provide patients with alternative pathways for obtaining robust government-funded screening in the event that a NT ultrasound is missed. These measures have been extented until June 30, 2021.


Prenatal Screening Ontario (PSO), supported by the Ministry of Health, is endorsing the following measures: 

Singletons: NT ultrasounds should be offered to all pregnant individuals whenever possible. If an NT ultrasound cannot be done, order the MSS.

  • MSS is the only validated serum screen in Ontario that can be used without ultrasound information, and can be done from 14 weeks to 20 weeks 6 days gestation. 
  • A concurrent change in the screening cutoff for MSS occurred, moving it from 1:200 to 1:350 (bringing the screening performance to a similar level as eFTS).
  • PSO cannot endorse first trimester serum-only screening because provincial data collected by BORN Ontario has insufficient numbers to allow for quality assurance.

Twins: Prioritize NT services. The Ministry of Health will temporarily fund NIPT for all twin pregnancies if a NT ultrasound is not available OR if maternal age is 35 or older at expected date of delivery. In these circumstances, NIPT can be ordered by any physician or nurse practitioner (effective April 6, 2020 until June 30, 2021).

  • NT ultrasounds are essential for twin pregnancies as serum screening alone is NOT possible for twin pregnancies (i.e. MSS is not a validated option). The value of NT ultrasounds extends beyond screening for Down syndrome and trisomy 18.

Higher-Order Multiples: The only option continues to be an NT ultrasound.

  • For triplets, quadruplets, or more, the only option is NT ultrasound (eFTS, MSS and NIPT cannot be done). 
  • Serum screening alone is not possible for higher-order multiples (i.e. MSS is not a validated option for twin pregnancies). 

COVID-19 and Prenatal Screening - Information for Pregnant Individuals 

As a pregnant individual in Ontario, you have the option of undergoing screening tests to give you information about the health of your baby. These tests consist of bloodwork and ultrasound, and are done at certain times over the course of the pregnancy. 

Prenatal Screening Ontario has been monitoring the access to prenatal screening services in the province during the COVID-19 pandemic. The data have shown that pregnant individuals still have access to prenatal screening tests, but obtaining these services has been more challenging during the pandemic. The COVID-19 pandemic has been impacting the availability of these tests and possibly your own ability to access them due to self-isolation. 

In response to COVID-19, there are temporary recommendations we are endorsing with the support of the Ministry of Health if certain tests are not available to you during this time, to ensure you still have access to high quality screening. The recommendations are applicable until June 30, 2021. 


Frequently Asked Questions

What is the typical pathway for prenatal screening?

The prenatal screening pathway usually starts with enhanced First Trimester Screening (eFTS), which includes a nuchal translucency ultrasound and bloodwork performed between approximately 11 weeks and 2 days and 13 weeks and 3 days gestation to provide you with information about trisomy 21 (Down syndrome) and trisomy 18 (Edwards syndrome). Depending on the type of test result received from eFTS, the typical next step in prenatal screening involves the detailed anatomy ultrasound, performed between 18-20 weeks gestation. Some patients may also have the option of pursuing OHIP-funded Noninvasive Prenatal Testing (NIPT). Alternatively, some patients may wish to pay out of pocket for this testing. NIPT can be performed as early as 9 weeks gestation depending on the company, and a dating ultrasound is recommended prior to having your blood drawn. 

What does COVID-19 mean for my access to prenatal screening?

Clinics and hospitals have been prioritizing and reallocating their resources due to COVID-19 and as a result, pregnant individuals may have had difficulties accessing some ultrasound services. At some labs, blood draws have to be done by appointment only resulting in longer than expected waits. Some individuals are not able to attend their ultrasound appointments due to being in self-isolation and may miss the time window for enhanced First Trimester Screening (eFTS). 

There have been ongoing efforts to provide patients with alternative pathways for obtaining robust government-funded screening during their pregnancies in the event that a time-sensitive screen or ultrasound is missed.  We are here to support you and your care provider in providing you with the most optimal care in light of your specific circumstances. 

I am not able to access a nuchal translucency (NT) ultrasound in my area. Can I still obtain prenatal screening?

If you are not able to access a NT ultrasound, the enhanced First Trimester Screening (eFTS) cannot be completed. However, a comparable alternative screen to eFTS is Maternal Serum Screening (MSS) that is done in the second trimester, between 14 weeks and 20 weeks 6 days gestation. The MSS is a validated test that has been in use for years in Ontario in circumstances where the first trimester screening test is missed. NT ultrasound information is not required for this test. The MSS uses a combination of maternal age and blood work to give information about trisomy 21 (Down syndrome) and trisomy 18 (Edward syndrome). You may also have the option of pursuing OHIP-funded Non-Invasive Prenatal Testing (NIPT) if specific criteria are met. If you do not meet criteria for OHIP-funded NIPT, you may still choose to pursue self-pay NIPT. NIPT can be done at any point in the pregnancy starting at 9 or 10 weeks gestation depending on the lab. We recommend that you check online before proceeding to your local blood collection lab (LifeLabs or Dynacare). 

I had my nuchal translucency ultrasound and I was told I must have the bloodwork done within 24 hours. However, I have not been able to get an appointment for the bloodwork within that time. Can I still have enhanced First Trimester Screening (eFTS)?

The nuchal translucency ultrasound must be done first, and while it is ideal and preferred that the blood test for eFTS is done on the same day following the ultrasound, this is not essential.  Blood samples can be accepted until 13 weeks and 3 days gestation, without affecting the accuracy of the screening.

What is the accuracy of the Maternal Serum Screening (MSS)? 

Changes to the MSS were implemented in April 2020 in the light of COVID-19, and its performance is currently similar to the eFTS. The detection rate of MSS is approximately 90%. This means that 90% of pregnant individuals carrying a baby with Down syndrome will have a screen positive result using MSS.  Because screening cannot detect all cases, approximately 10% of pregnancies with Down syndrome will receive a screen negative result using MSS.

I was not able to access a nuchal translucency (NT) ultrasound but my doctor sent me for a prenatal screening blood draw and I am less than 14 weeks gestation. If my blood has already been drawn, what result can I expect from this?

If your blood has been drawn for screening in the first trimester, some blood labs will not process this sample and will recommend that you return for a blood draw after 14 weeks gestation to initiate a Maternal Serum Screening (MSS). Some labs may be able to provide you with a first trimester MSS if they receive a blood sample from you and there was a dating ultrasound done earlier in the pregnancy. 

I am over 14 weeks gestation and I have not had access to any ultrasounds in my pregnancy. What are my options for screening? 

If you have missed the window for a dating and a nuchal translucency ultrasound, please be assured that you will still have options for prenatal screening. The Maternal Serum Screening (MSS) can be done based on the first day of your last menstrual period if you are unable to access an ultrasound prior to having your blood drawn. You may also have the option of pursing OHIP-funded or self-funded Non-Invasive Prenatal Testing (NIPT) which can be done at any point until the end of the pregnancy. Please note that the performance of both MSS and NIPT may be affected if the last menstrual period dating is not accurate, or if there is more than one fetus and this information is not known at the time of the blood work.  

I would like to do NIPT. How can I have my blood drawn and will there be a delay in obtaining results?

There may be a reduction in the number of lab collection centers offering blood draw services. At some labs, you may be able to have a blood draw by appointment only. We encourage anyone planning to have their blood drawn for NIPT to check with Dynacare and LifeLabs for the most up-to-date information on which locations are in operation. You are encouraged to contact the LifeLabs Genetics Helpline if you wish to have the Panorama NIPT Prenatal test, and are unable to book an appointment within the next two business days. There are currently no changes to how long it takes for results to be reported.  

I am in self-isolation and I am worried about being able to have prenatal screening. What are my options? 

It is important to follow public health directives during this time and follow social distancing or self-isolation guidelines as prescribed. We are anticipating that some individuals in self-isolation will not be able to attend appointments during that time and may miss the window for certain time-sensitive blood tests and ultrasounds. Be assured that you will still have the option of doing prenatal screening tests once you are no longer in self-isolation, and those options will be dependent on your gestational age and other factors. Please contact your health care provider for further guidance if you find yourself in this situation. 

I am expecting more than one baby (e.g. twins, triplets). Do I have the same options for prenatal screening as those who carry one baby?

  • If you are carrying twins, your options for prenatal screening are enhanced First Trimester Screening (eFTS) and Non-Invasive Prenatal Testing (NIPT). The Maternal Serum Screening (MSS) is not possible for pregnancies with twins. Prenatal Screening Ontario is encouraging that NT ultrasounds be made available for individuals carrying twins or more, regardless of whether NIPT was initiated. NT ultrasounds can provide valuable information with regards to the health of the babies. 
  • The Ministry of Health temporarily approved funding for NIPT in the context of twin pregnancies if you do not have access to an NT ultrasound OR if you are 35 years or older.
  • If you are having triplets, quadruplets, or more, your option for screening the pregnancy for chromosome differences is limited to NT ultrasound only (eFTS, MSS and NIPT cannot be done). 

 Other COVID-19 Resources


You may find the following resources helpful, if you have other questions about how COVID-19 may impact maternal, pregnancy and newborn health:

COVID-19 Vaccinations

 Staying Up-To-Date


While blood collection laboratories and obstetrical ultrasound units are providing essential health care services, sites may have implemented new protocols for patient visits.  If you are unable to obtain a first trimester ultrasound, please consult your physician to discuss alternative screening options.  Prior to seeking blood testing or ultrasound, we recommend consulting the websites of your chosen location to learn about any changes in service, hours, or closures.

Please be aware that sites conduct their own COVID-19 screening to defer services to individuals that pose a higher risk. We encourage you to contact the individual laboratories and ultrasound units to learn about their specific guidelines. For instance, the sites may not offer service if you have travelled outside of Canada within the last 14 days or if you have fever and/or respiratory-like symptoms such as coughing, shortness of breath, sore throat and runny nose.

If you are concerned that you may have been exposed to, or are experiencing symptoms of COVID-19, please start by visiting the Ministry of Health website and taking their self-assessment.

The current situation with COVID-19 is changing daily and we will update the Prenatal Screening Ontario website frequently to keep you informed. As always, Prenatal Screening Ontario’s genetic counsellors are available to answer your questions and can be reached by calling 1-833-351-6490, Monday to Friday from 8am to 4pm.