Amniocentesis is the most commonly performed invasive test for prenatal
diagnosis. It is usually performed late in pregnancy (common human gestation is
about 40 weeks. Amnio is usually done at 36) to test for lung development
but can also be used to screen for genetic abnormalities (Down Syndrome etc.)
A needle is inserted through the mother's abdomen into the uterus, while the physician
pushes the baby's head out of the way, and fluid is drawn and sent
to a lab for analysis. It takes about 10-20 minutes. Though a local
anesthetic is used the mother does feel pressure and often quite a bit of
discomfort. The needle does not touch the baby, whose heartbeat is monitored for
signs of distress.
Generally, other non-invasive tests are tried first and amnio is done later due to
the risk (which is slight) of fetal injury.
Pregnancy Questions and Answers by Peg Palumbo
What to Expect
When You're Expectiong A.Eisenberg, H. Murkoff, S. Hathaway
This write up is for masukomi and will soon be part of a parenting metanode - please /msg me is you would like to add factual material about pregnancy, childbirth, early childhood, or adolescence. Parenting experience prefered but not mandatory.