Noninvasive Prenatal Testing for Fetal Aneuploidy ABSTRACT: Noninvasive prenatal testing that uses cell free fetal DNA from the plasma of pregnant women offers tremendous potential as a screening tool for fetal aneuploidy. Cell free fetal DNA testing should be an informed patient choice after pretest counseling and should not be part of routine prenatal laboratory assessment. Cell free fetal DNA testing should not be offered to low-risk women or women with multiple gestations because it has not been sufficiently evaluated in these groups. A negative cell free fetal DNA test result does not ensure an unaffected pregnancy. A patient with a positive test result should be referred for genetic counseling and should be offered invasive prenatal diagnosis for confirmation of test results. Noninvasive prenatal testing that uses cell free fetal DNA from the plasma of pregnant women offers tremendous potential as a screening tool for fetal aneuploidy. Circulating cell free fetal DNA, which comprises approximately 3–13% of the total cell free maternal DNA, is thought to be derived primarily from the placenta, and is cleared from the maternal blood within hours after childbirth (1). Recently, cell free fetal DNA analysis has become clinically available for women at increased risk of fetal aneuploidy. Early attempts to detect trisomic fetuses using cell free fetal DNA required the use of multiple placental DNA or RNA markers, which made the screening test time consuming and expensive (2–4). Recently, a number of groups have validated a technology known as massively parallel genomic sequencing, which uses … Continue reading →
New prenatal screening test for Down syndrome raises questions LEISA SCOTT IT RAINED the day they got the news. Big, pelting drops, as if some screenwriter well-versed in melodrama was dictating the scene. Annie Love couldn’t take the call. She’d been going “slowly nuts” waiting for diagnosis day to arrive and was only just holding herself together. Her husband, Ben, answered the phone. He nodded. Then he mouthed the words. “It’s positive. Baby has Downs.” They cried. Huge, heaving sobs to rival the rain. In the days and weeks that followed, they’d pull themselves together, then lose it all over again. And they grieved. This was not the picture they had of their family. This baby was meant to be “normal” just like Sam, then 4, and Charlie, then 2. Now the picture had changed, fuelled by stereotypes: an overweight kid with a bad haircut being teased, a life on the fringes. But they’d already decided after many heart-wrenching talks in the preceding four weeks between suspicious scan and confirming amniocentesis that they would have the baby. If he had Down syndrome, they’d paint a new picture. So they prepared. Months of grief gave way to a readiness and a joy. Everyone close to them knew their baby would be born with Down syndrome. Now it was time to get on with it. They wrote a birth plan. No-one in that delivery room was to be negative. This was their baby and they were happy. He arrived at 2.55am on … Continue reading →
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