MOHLTC - Children's Health - Ontario Prenatal Screening - What are your chances of having a baby with one of these conditions?

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Ontario Prenatal Screening

Chances of having a baby with one of these conditions

Are Prenatal Screening Tests right for you?

Do you want to have prenatal screening or not?

Early Prenatal Screening

Later Prenatal Screening

Understanding your results

Diagnostic tests

Timing of Screening Tests

What are your chances of having a baby with one of these conditions?

It is important to remember that most babies are born healthy.

The chance of having a baby with a chromosome condition like Down syndrome and trisomy 18 increases with the age of the mother as shown in the Table below.

Chance of chromosome conditions with varying maternal age:

Mother’s Age (years)	Chance of Down syndrome	Chance of any chromosome condition including trisomy 18, Down Syndrome and others
20	1 in 1,650	1 in 530
25	1 in 1,250	1 in 480
30	1 in 950	1 in 390
35	1 in 385	1 in180
40	1 in 100	1 in 65
45	1 in 30	1 in 19
Every woman, no matter what age, has a 2-3% chance (2 or 3 chances in 100) of having a baby with some kind of birth defect. Birth defects can include conditions like heart problems and extra toes.

Remember…
You might decide to have prenatal screening because you want to find out your chance of having a baby with Down syndrome, trisomy 18 or open neural tube defect. This is determined from your age, the blood tests and/or ultrasound.

A screening test gives you more information about your chance of having a baby with one of these conditions than the chance shown in the table above.



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