Years later, when each sister became pregnant, she had prenatal tests.
So we decided not to do any prenatal diagnostic tests unless something goes wrong.
Here's a look at the most common prenatal tests you might undergo over the next nine months.
And there are no prenatal tests that can detect it.
There is also no prenatal test to determine whether an unborn child has the disease.
The most common prenatal tests you can expect to undergo at some point during your pregnancy.
As a result, more women are facing increasingly difficult decisions about which prenatal tests to accept and how to act on their results.
"Women over 30 are being pressured to get a whole battery of prenatal tests," she said.
They knew from prenatal tests that their daughter would be born without a brain cortex.
From the first trimester to delivery, get the information you need about prenatal tests.