Amniocentesis is done to detect genetic and chromosomal malformations in the fetus. The procedure is performed between weeks 16-23 of the pregnancy by drawing a small amount of amniotic fluid from the uterus. The procedure is performed at Shaare Zedek Medical Center by an expert physician with the help of an ultrasound.
Two main techniques are used to analyze the genetic material – karyotype (done under a microscope) and CMA (Chromosomal Microarray Analysis) - a new method that allows for a much more accurate analysis.
Though the CMA is more expensive than the karyotype analysis, Shaare Zedek offers this test without extra charge to each woman undergoing amniocentesis. Each woman also receives a genetic counseling prior to the procedure, also without extra charge. The geneticist provides explanations about the procedure and the various findings that could be detected. If there are unusual findings, a second counseling session might be scheduled.
Through amniocentesis we can detect a wide range of common genetic diseases, the most common of all is Down syndrome - caused by an excess copy of the 21st chromosome.
Amniocentesis also helps detect rarer defects in specific genes, if there is prior knowledge of the genetic malformation. Examination of specific genes is usually done when one of the parents has been diagnosed as a carrier of a genetic disease or if there is any other reason to suspect that the fetus may have a defected gene. Many diseases can be detected in this manner, such as CF, Tay-Sachs, Familial Dysautonomia and more.
Each woman undergoing amniocentesis at Shaare Zedek will be cared for by our best experts.
Women over the age of 35 receive full funding from the Israeli Ministry of Health; however, this limit is arbitrary, set at a time when there were no other reliable tests and the main method to determine the chance of genetic fetal syndromes was according to the mother's age. Today there are many non-invasive tests to determine the chance for genetic diseases, among them nuchal translucency, alpha-fetoprotein, combined tests and more. Yet amniocentesis is still the only way to definitively confirm or rule-out a fetal chromosomal problem.
The recommendation for amniocentesis is done on an individual basis for each woman according to her personal history as well as her wishes and position on termination of pregnancy in case the fetus is diagnosed with a genetic defect.
As with any invasive procedure, amniocentesis has risks, the main one being a miscarriage. However, on the whole, the risk is minimal. Other rare complications include traumatic injury to the fetus and infection.
Comprehensive information about the risks and benefits of the test will be provided before the procedure so that the parents can make an informed decision.
Obstetric Ultrasound Unit