Considerations When Ordering Multiple Marker Screening

Did you know?

When ordering MMS, there are instructions on the requisition to follow:

Only select eFTS or STS below if singleton pregnancy and:
1. NIPT has not been ordered in this pregnancy.
2. NIPT has been ordered, but has been uninformative.

Let's take a look at how often these instructions were followed when ordering MMS in FY 2020-2021.

Correct Ordering of MMS

Pregnant individual

Meet Yasmin. Yasmin is a 32 year old individual at EDD with a singleton pregnancy. After a discussion with her health-care practitioner and thinking about whether or not prenatal screening was right for them, Yasmin chose to have prenatal screening. Her health-care practitioner determined that she did not meet the funding criteria for OHIP-funded NIPT nor did she opt to self-pay for NIPT at the time of her appointment, therefore, eFTS was offered and accepted. It was ordered by following the How to Order eFTS instructions on the PSO website.

Woman smiling

Meet Alexis. Alexis is a 41 year old individual at EDD with a singleton pregnancy. Since Alexis was aged 40 and beyond at EDD, they initially had OHIP-funded NIPT. However, Alexis' NIPT result was uninformative, and a second NIPT attempt that was recommended by the NIPT lab was also uninformative. Alexis was still interested in knowing the chance for their pregnancy to have trisomy 21 or trisomy 18. Their health-care practitioner read the instructions on the MMS requisition and determined that they could order MMS for Alexis (either eFTS or STS depending on the gestational age) since Alexis' NIPT result was uninformative. They also noted that Alexis could be referred to their local Genetics/Maternal Fetal Medicine Centre for discussion of diagnostic testing.

Ordering prenatal screening for an individual who will be 40 years and beyond at EDD, or for an IVF pregnancy with an egg aged 39 years and beyond at retrieval? Check out Taylor's Story for more information.

Incorrect Ordering of MMS

Pregnant individual

Meet Jade. Jade is a 29 year old individual with a singleton pregnancy. They did not qualify for OHIP-funded NIPT based on the funding criteria, but choose to self-pay for NIPT. Jade's NIPT result came back low risk for trisomies 13, 18 and 21. At a later date, eFTS was also ordered for Jade, despite already having an informative NIPT result. Jade's eFTS result came back screen positive for trisomy 21.

Initiating MMS (eFTS or MSS) at the same time as NIPT or after an informative NIPT result can be confusing because it can lead to conflicting results, like Jade's. In this scenario, the NIPT result is considered the more accurate screening result, given its increased sensitivity for trisomy 21. Nevertheless, a referral to your local Genetics/Maternal Fetal Medicine Centre can be considered for further discussion.

Like Jade, 1.9% of pregnancies inappropriately had MMS ordered after an informative NIPT result.

Data Notes:

BORN Ontario, 2020-2021

Number of pregnancies with correct and incorrect ordering of MMS for singleton pregnancies among Ontario residents.

1. Data were extracted from the BORN Information System (BIS) on 4 Oct, 2023. Note that data submission to the BIS is both voluntary and open to updates and amendments. This table represents a snapshot of the BIS on the date of data extraction.

2. Fiscal year was defined by estimated date of delivery. Each fiscal year ranges from April 1 to March 31, inclusive.

3. The cohort timeline was defined by pregnant person estimated date of delivery.

4. Only singleton pregnancies were included in this analysis.

5. Only Ontario residents were included in this analysis.

6. BORN Ontario strives to better understand how our data can be used to inform health system partners on the intersection between social determinants of health, indigeneity, and perinatal and child health outcomes. This table includes data that may or may not support reflections on indigeneity and health equity. We cannot conclusively or accurately identify the extent to which BORN data reflect indigeneity and equity-deserving groups. This pursuit is ongoing, and we appreciate your support and ideas related to enabling our efforts in pursuit of more equitable outcomes and programming.

Return to Main Report