An amniocentesis is a type of prenatal test that involves inserting a needle through the mother's abdomen to collect a sample of amniotic fluid, and subsequently testing the amniotic fluid to examine the baby's chromosomes. However, amniocentesis can be controversial for two reasons: the test carries a small risk of causing a miscarriage, and the results of the test can also lead to people deciding to terminate their pregnancies. Thus, some pregnant women fear the test, others decry its use, and still others just aren't sure what all the fuss is about.
Because they have an increased risk of having a baby with a chromosome disorder, moms over 35 may be offered an amniocentesis or CVS as a routine test. But most other moms are not automatically offered an amniocentesis unless their babies are determined to have a high risk of chromosome disorders. An example would be if the triple or quad screen blood test showed elevated odds of a particular condition.
So if amniocentesis is just a test for chromosome disorders, why are people so concerned about it, one might wonder.
Probably the biggest reason people are concerned about amniocentesis is the small added risk of miscarriage -- and the fact that a range of numbers are used to estimate this risk. Reliable research shows that the risk of an amniocentesis inducing a miscarriage is somewhere around 1 in 400 using modern methods, but some sources still use the older, scarier estimates of a 1 in 200 or even a 1 in 100 risk of miscarriage. And naturally, some people feel that any added risk -- no matter how small -- is too high.
The other reason why people may be passionately against amniocentesis is because some parents decide to terminate their pregnancies when they learn that the baby has a chromosome disorder. The most common disorder people think of when discussing amniocentesis is Down syndrome, a condition that causes developmental and cognitive impairments. Some people are morally opposed to termination of babies with Down syndrome, especially because the condition doesn't usually cause life-threatening health problems, and thus people's moral judgments on termination may extend to the amniocentesis test because the test can be a catalyst for people deciding to terminate their pregnancies.