Amniocentesis

Brief Introduction

Amniocentesis is the process by which a thin needle is inserted through a womens abdomen into her womb, a sample of the amniotic fluid surrounding her growing fetus is taken out and analysed to acquire information about the baby's health.

This procedure is an important development in the technologies of prenatal diagnostic techniques as it allows parents an insight into possible diseases and complications that their baby might develop before birth at an early stage of its development.

Although it is a very useful technique in diagnosing up to several hundred fetal complications there are also many risks associated with this invasive method of extraction of fetal cells as well as ethical issues which will also be explored. A brief history of the development of amniocentesis will be explained, as well as the key disorders which may be detected using it. Lastly we will explore the accuracy of this test against other prenatal diagnostic techniques and highlight current research being conducted.

Historic Background

Procedure

Who is eligible for the test?

Since the procedure is invasive and not without a number of risks, the mother is tested before to determine whether she is at a higher risk than average of having a child with a chromosomal or neural tube defect. These tests include:

Checking for abnormal ultrasound features.
Maternal age is considered, women older than 35 are at a higher risk of having children with chromosomal disorders.
History of chromosomal disorders in the family, testing if the parents are Rh positive or Rh negative.
History of previous children born with a genetic defect.

When can the test be taken?

An amniocentesis test is most commonly performed between weeks 15 to 16 of gestation which is during the second trimester of pregnancy, however it is able to be performed anytime between weeks 14 to 20. This timing is preferred over an early amniocentesis which is performed in the first trimester during weeks 11 to 14 as the earlier the test is performed the higher the risk of miscarriage, as much as 3 times greater. The reason an early amniocentesis option is offered to women is since the delay in tissue analysis of about 2 weeks means if an abortion is required it is physically and emotionally easier earlier on in the pregnancy. If an early diagnostic test is requested Chorionic Villus Sampling (CVS) is suggested as it carries less risk of miscarriage and complications than amniocentesis in the first trimester.

Risks

Disorders Detected

Diagnostic Accuracy

Ethical Issues

Current Research

References

2010 ANAT2341 Group Projects

Glossary Links

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Cite this page: Hill, M.A. (2024, April 23) Embryology 2010 Group Project 3. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/2010_Group_Project_3

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