The above picture illustrates amniocentesis, a procedure to test for birth abnormalities including spina bifida*, anencephaly*, and Rh disease*. With the assistance of an ultrasound (imaging of abdomen using high frequency sound waves), a fine needle is guided through the mother’s abdomen/uterine wall to then extract the amniotic fluid from the uterus (womb). Afterwards, the extracted material is sent to the laboratory for cytological analysis which will determine if the fetus is healthy or if further testing and/or possible treatment is necessary. It is important to note that although the amniotic sac (membrane which encloses and protects child) must be punctured in order to obtain fluid, the sac soon heals and the withdrawn fluid is replenished.
As this procedure is quite invasive, it is only offered under specific circumstances. These circumstances include any high risk pregnancy due to the mother’s age (generally 35 or older), history of genetic disorder(s), or from receiving abnormal results from a prenatal prescreening test such as an alpha fetoprotein screening. In an alpha-fetoprotein test, the level of alpha-fetoprotein in the mother’s blood is measured to see if further testing is necessary. Alpha fetoprotein is a protein produced in the fetus’, or unborn child’s, liver. Abnormal test results could signal the presence or development of an open neural tube defect i.e. spina bifida, etc. Fetal maturation includes a process called neurulation in which the neural tube (tube that connect brain to central nervous system) develops and eventually closes in on itself to ensure the growth of other neural tissue. In open neural tube defects, the neural tube does not close typically resulting in death of the fetus. As amniocentesis is a serious procedure to undergo, it’s important to be aware of all of the risks involved; however it’s also pertinent to know that amniocentesis yields highly accurate results and could make a significant difference
References: Gylys, B. & Wedding, M. (2009). Medical Terminology Systems: A Body Systems Approach (6th ed.). Philadelphia, PA: F.A. Davis Company.