Enhanced First Trimester Screening (eFTS)

Talk with your health-care provider if you would like to get eFTS. In Ontario, this test can be ordered by:

• doctors (such as family doctors, obstetricians)
• nurse practitioners
• midwives

If you don’t have a family doctor, you can still arrange this test through a walk-in clinic. Use Health811 to find walk-in clinics near you. 

eFTS can be done from 11 weeks 2 days to 13 weeks 3 days of pregnancy. During this time window, you will first have a special ultrasound called the 11-14 week (nuchal translucency) ultrasound, followed by a blood test. 

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You should not have eFTS if you:

• already have a "low risk" result from Non-Invasive Prenatal Testing (NIPT), or you are waiting for your NIPT results. 
• had a vanishing" twin / co-twin demise. This is a pregnancy that started as twins, but one of the twins miscarried.
• are expecting more than one baby (twins, triplets, quadruplets etc). 

eFTS detects most pregnancies with trisomy 21 and trisomy 18. As with other screening tests, eFTS cannot detect all pregnancies with these chromosome differences. The ultrasound can give extra information about the baby's health, including some serious birth defects. 

This screening test will combine all the information below to tell you about the chance to have a baby with trisomy 21 and trisomy 18:

• Your age at the time of birth
  • You have a higher chance for chromosome differences like trisomy 21 and trisomy 18 as you get older. If you got pregnant through in vitro fertilization, it is the age of the egg that is used. The egg may be your own or from a donor.
• 11-14 week (nuchal translucency) ultrasound result
  • The nuchal translucency (NT) refers to the pocket of fluid at the back of the baby's neck. This pocket of fluid is measured during the ultrasound. When there is more fluid than what we typically see, there is an increased chance for trisomy 21, trisomy 18 and other conditions.
• Blood test result
  • The blood test for eFTS will measure the amount of 3 or 4 proteins or chemicals made by your pregnancy.
• Other information about you
  • Your health-care provider will ask you some questions about you that improve the accuracy of test. You will be asked about your racial identity, diabetes status, smoking history in the pregnancy, weight and whether the pregnancy happened through in vitro fertilization. 

The results are expected to be received by your health-care provider within approximately 7 working days. Talk to your health-care provider about how they plan to give you these results. 

When you get your eFTS report, it will most likely say that you have a “screen negative” result. This means that you have a lower chance to have a baby with trisomy 21 and trisomy 18.  It does not mean "no chance". 

Some individuals will get a “screen positive” result, which means that there is a higher chance to have a baby with trisomy 21 or trisomy 18. It does not mean your baby definitely has one of these chromosome differences. You would have more options for testing, including publicly-funded NIPT and diagnostic testing.

You might have the option of doing another prenatal screening test, called Non-Invasive Prenatal Testing (NIPT), instead of eFTS. In this section, you will learn how eFTS and NIPT compare to help you make a decision. 

The results presented in this visual are based on the sensitivity and specificity of eFTS and NIPT from actual Ontario pregnancies with an estimated date of delivery between September 2016 and December 2023 that underwent prenatal screening (twins were excluded). The incidence of trisomy 21 in this group was 1 in 394. The figures were applied to this fictitious population of 50,000 people. View more details about the performance of prenatal screening tests.

Accessible version of above visual (text only)

eFTS and NIPT side-by-side

Accessible version of above visual (text only)

Screening tests can give false positive or false negative results.

False positive

A false positive is when a pregnant individual gets a "screen positive" or "high risk" result but the baby does not actually have trisomy 21. Both screens have false positives. However, there are more false positives through eFTS than NIPT.

False negative

A false negative is when a pregnant individual gets a "screen negative" or "low risk" result but the baby actually has trisomy 21 (missed case). Both screens have few false negatives. However, there are more false negatives through eFTS than NIPT.

To help you understand the accuracy of eFTS and NIPT, view the type of results that 50,000 people can get if they choose prenatal screening.

Results of 50,000 people who have eFTS or NIPT