Achievements in the prenatal diagnostics made genetic testing much safer. But what do the experts say?
Genetic screening, which takes place before conception, during the first trimester and second trimester of pregnancy, is a conventional blood collection and does not pose any risk for a mother or a child. You are threatened by the unpleasant feeling of needle-stick or a small bruise only.
The risks of the majority of genetic testing are mainly emotional, rather than physical in nature, says Ellen Simpson, Ph.D., consultant of Genetics Prenatal Diagnostic Center at the Medical Center of the University of California. So, if the test results before conception show that you or your partner is a carrier of the mutated gene that can be passed to your future children, it is fraught with severe stress.
If in the course of research pregnancy is referred to a group of genetic risks, you may be asked to pass two other genetic diagnostic tests – amniocentesis and chorionic villus sampling – both of them have potential side effects.
During amniocentesis a doctor takes a small amount of amniotic fluid (which contains some embryonic cells) by inserting a needle through the abdomen into the uterus to diagnose a lot of genetic abnormalities, including Down’s syndrome, spina bifida, sickle cell anemia, cystic fibrosis, and Tay-Sachs disease. After this procedure, one or two per cent of women have spotting, cramping, or leaking amniotic fluid, and a very small percentage, 1 of 200 may have a risk of miscarriage.
During chorionic villus sampling needle is inserted through the cervix or abdomen to take a sample of placental tissue. Thanks to chorionic villus sampling it is possible to diagnose Tay-Sachs disease, sickle cell anemia and other genetic diseases. The risk of miscarriage after chorionic villus sampling is about 1 of 100. There is also a very small risk of uterine infection.