Early Aneuploidy Screening Options
- Posted on: Mar 31 2020
Submitted by Meghan Delaney, WHNP
During your initial obstetrical appointments in our office, we will spend time with you discussing body changes, symptoms and planned care and testing moving forward. One area that seems to be a source of confusion and questions are your options for aneuploiody screening.
Aneuploidy is the medical term for chromosomal abnormalities in your baby – one common example would be Down Syndrome. There are two optional early screening tests that will be offered to you. The first is NIPT (Noninvasive Perinatal Testing). This involves a blood draw from the mother done after 11 weeks. At this point it is possible to detect fetal DNA in maternal blood. A specialized lab can evaluate this sample for changes in chromosomes that would be associated with an abnormality. Since chromosomes are checked this test is also able to report gender. Although highly accurate it is still considered a screening test and any abnormality would require additional consultation and testing with a specialist. This test is most commonly offered to patients who have increased risk of having a baby with a chromosomal defect such as mothers age over 35 although any patient may opt to have the test done.
The second early screening test offered is Combined First Trimester Screening/Nuchal Translucency. This is a combination of a blood draw from the mother and a detailed ultrasound measuring the thickness of the fetal neck fold (nuchal fold) done between weeks 11-13. Any abnormalities in either of these results would increase the risk of the fetus having a chromosomal abnormality; at this point you would again be offered additional testing and consultation with a specialist to get a definitive diagnosis. If the screening test is normal risk of the fetus having a chromosomal abnormality is considered low. This test is less accurate than the NIPT but more likely to be covered by insurance in low risk women. We welcome a discussion and questions in regard to this topic at any of your first trimester visits and look forward to caring for you during this exciting time!
Posted in: Obstetrics