Amniocentesis
Genetic amniocentesis is a procedure offered at Piñon Perinatal for diagnosis of certain genetic disorders, such as chromosome abnormalities. You may be offered an amniocentesis if you will be 35 or older at the time of delivery, if birth defects are seen on ultrasound, or if screening tests return with an abnormal result. The results of amniocentesis will show the baby's chromosomes, which can diagnose or exclude conditions such as Down syndrome. Levels of certain substances made by the baby during pregnancy are measured to assess risk for neural tube defects such as spina bifida.
An amniocentesis procedure is done with ultrasound guidance, so that a pocket of fluid away from the baby can be found. The amniotic fluid, which surrounds the baby during the pregnancy, contains skin cells shed by the baby. A small sample of the fluid is taken through a thin needle, which does not touch the baby, and the fluid is sent to a laboratory for testing. There is a small risk of miscarriage with amniocentesis, which occur with fewer than 1 out of 750 procedures performed. The procedure is usually performed after 15 weeks of pregnancy. Once results from the procedure are made available, a genetics specialist will contact you to review them.
CVS
Chorionic villus sampling (CVS) is a prenatal procedure to test for chromosomal abnormalities and other genetic problems. The procedure involves taking a sample of tissue from the placenta, a structure in the uterus that provides blood and nutrients from the mother to the fetus. It may be performed for one or more of the following conditions:
Family history or previous child with a genetic disease, or chromosomal or metabolic disorder
Maternal age over 35 years by the pregnancy due date
Risk of a sex-linked genetic disease
Previous ultrasound with questionable or abnormal findings
There are two types of CVS procedures:
Transcervical – a catheter is inserted through the cervix into the placenta to obtain the tissue sample
Transabdominal – a needle is inserted through the abdomen and uterus into the placenta to obtain the tissue sample
The type of procedure performed depends upon various factors including anatomy, placental location, and the presence of uterine fibroids. CVS is typically performed between the 10th and 12th weeks of pregnancy, which allows for earlier diagnosis of some genetic disorders when compared to an amniocentesis. There is a low risk of miscarriage with CVS, which is similar to that of amniocentesis.
Once results from the procedure are made available, a genetics specialist will contact you to review them.