Enhanced First Trimester Screening (eFTS)

enhanced First Trimester Screening (eFTS) is a screening test available in the first trimester of pregnancy (when you are about 3 months pregnant). eFTS involves an ultrasound and a blood test, and therefore poses no risk to the pregnancy. This testing can tell you the chance for having a baby with trisomy 21 (Down syndrome) and trisomy 18 (Edwards syndrome).

How to Get 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

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

Download Instructions

For Health-Care Providers

Requisitions and How to Order

Who Should Not Have eFTS?

eFTS should not be done when:

you already have a "low risk" result from Non-Invasive Prenatal Testing (NIPT), or you are waiting for your NIPT results.
there is more than one baby (twins, triplets, quadruplets etc).
there is a "vanishing" twin / co-twin demise. This is a pregnancy that started as twins, but one twin is lost and the other survives.
the pregnancy happened after in vitro fertilization (IVF) and the embryos had Preimplantation Genetic Testing (PGT-A) during that process. PGT-A involves screening embryos for chromosome differences to help decide which embryos to transfer into the uterus. eFTS is not recommended for pregnancies that had PGT-A, since PGT-A is considered to be a better screen for trisomy 21, trisomy 18 and other chromosome differences.

How The Test Works

The test will combine all the information below to tell you about the chance to have a baby with trisomy 21 (Down syndrome) and trisomy 18:

Your age at the time of birth

There is a higher chance for chromosome differences like trisomy 21 and trisomy 18 as the age of the pregnant individual increases. If the pregnancy happened through IVF, it is the age of the egg that is taken into account (whether it is your own or a donor egg).

Nuchal Translucency (NT) 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 at the time of 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 levels of 3 or 4 different hormones (or proteins) that are present in your blood. The hormones are made by the pregnancy (placenta or the baby).

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.

How Long Does It Take to Get Results?

The eFTS result will be shared with your health-care provider within approximately 5 working days. Talk to your provider about how they plan to share these results with you.

What Will the Results Mean?

When you receive your eFTS report, it will most likely say that you have a result that is “screen negative”. This means that you have a lower chance to have a baby with trisomy 21. If your report does not include information about trisomy 18, you can assume you have a "screen negative" result for this chromosome difference as well.

Some individuals will get a “screen positive” result, which means that there is a have a higher chance to have a baby with trisomy 21 or trisomy 18. More testing will be offered to you, including OHIP-funded NIPT.

In both "screen negative" and "screen positive" situations, the report will also give you a specific chance that your baby has trisomy 21. For example, a possible result may be a 1 in 50 or 1 in 700 chance that the baby has trisomy 21.

How Does eFTS Compare to NIPT?

You may 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.

eFTS and NIPT Side-by-Side
	eFTS	NIPT
When in the pregnancy is it done?	11 weeks 2 days to 13 weeks and 3 days	9 or 10 weeks and later
What does it include?	blood work NT ultrasound	blood work
What does it screen for?	trisomy 21 trisomy 18	trisomy 21 trisomy 18 trisomy 13 sex chromosome differences
Is it funded by OHIP?	Yes	Yes, in certain situations
Detection rate (trisomy 21)	89%²	More than 99%³
False positive rate (trisomy 21)	6%⁴	0.1%⁵
Detection rate (trisomy 18)	85%	96%
False positive rate (trisomy 18)	Less than 1%	Less than 0.1%
Can it be done for a twin pregnancy?	No, it can only be done if you are expecting one baby	Yes, it can be done if you are expecting one or two babies

Notes

The detection rate and false positive rate for the screening tests were obtained from Ontario data (twin pregnancies were excluded). View more details about the performance of these tests.

²89% of people that are carrying a pregnancy with trisomy 21 will get a “screen positive” result using eFTS. Screening cannot detect all cases: approximately 11% of pregnancies with trisomy 21 will be missed with this test.

³More than 99% of people that are carrying a pregnancy with trisomy 21 will get a “high risk” result using NIPT. Rarely (less than 1% of the time), people that are carrying a pregnancy with trisomy 21 will be missed with this test.

⁴6% of people that are not carrying a pregnancy with trisomy 21 will get a “screen positive” result using eFTS.

⁵Less than 0.1% of people that are not carrying a pregnancy with trisomy 21 will get a “high risk” result using NIPT.

Limitations

eFTS has some of the following limitations:

Not diagnostic - eFTS can tell you the chance of having a baby with trisomy 21 or trisomy 18, but will not give you a definitive "yes" or "no" answer about these chromosome differences. Screening tests are not 100% accurate – the test can miss pregnancies with trisomy 21 or trisomy 18, or it can tell you the baby has one of these chromosome differences when in fact, the baby does not.
Does not screen for "everything". - this test does not specifically screen for conditions other than trisomy 21 or trisomy 18, although additional information about the baby's health can be discovered during screening.