Chorionic Villus Sampling (CVS)
Genetic Screenings (AFP, Prenatal Risk Profile/Triple Screen, and Ultrasounds) seek to discern which pregnancies carry an increased risk of fetal abnormalities; it does NOT tell you which babies have abnormalities. Because of this, there can be false positives in the screening process which can be quite emotionally alarming to the parents if they don't understand this; the final word on whether your baby possesses the abnormality he/she is at risk for, often won't come until his/her birthday--which leaves many parents on edge for much of the nine months. Most women who do receive a "positive" in one of these tests (indicating increased risk of a fetal abnormality), however, go on to deliver a perfectly healthy baby. If you decide to participate in the genetic screening for whatever reason, and the results come back "abnormal", your provider will more than likely recommend further testing.
Diagnostic Tests (Chorionic Villus Sampling and Amniocentesis) can give you more accurate results, though the risks for the baby are much higher with these invasive tests.
Genetic screening, as with any test/procedure done during pregnancy, is entirely optional. You may choose to decline for any reason. In deciding whether or not a particular genetic screening is right for you and your baby, you will want to consider:
the benefits of the test--detection of abnormalities such as Downs Syndrome, spina bifida, etc.
the risks of the test--ranging from stress--sometimes undue--on the parents to loss of the baby (miscarriages can and do happen with many of these tests because of the test invasiveness--even to those babies who were otherwise perfectly healthy and thriving before the test)
acceptable courses of action for your family--it is often said that if an abortion is not an option for you, than genetic screening will not make any difference--other than possible limited preparation for the handicapped child
family history of genetic disorders
This genetic screening procedure can be done at 10-12 weeks and involves removing a sample of the tissue near the baby which will eventually become the placenta. This tissue sample must be taken through the cervix, instead of through the belly as in the amniocentesis. This test CANNOT detect spina bifida, however, like the amniocentesis. There also seems to be a significant number of false positive AND false negative results associated with the CVS.
There are high risks associated with this test including, but not limited to: infection, bleeding. limb deformities in the baby (the earlier in pregnancy, the more likely--probably due to interference of the blood supply), and miscarriage. Because of these risks, CVS is contraindicated for women with a history of miscarriage, an incompetent cervix, or premature labor.
Many health providers feel that the risks associated with CVS outweigh any benefits.