CHILDREN BY CHOICE ASSOCIATION INCORPORATED

Prenatal Testing

Any pregnant woman can choose to have prenatal testing performed, however it is most commonly utilised if:

• You already have a child with a serious disorder.
• You or the man involved in the pregnancy have a serious disorder which may be passed onto the pregnancy.
• You have a relative with a serious disorder, or the relative has an affected child.
• You have a family history of a disorder that only affects boys. Women may be “carriers” of the disorder.
• You are in your mid 30’s or older.

Not all birth defects can be detected by prenatal diagnosis, however it is highly accurate and can detect a large number of abnormalities. Types of testing include:

Ultrasound

With an ultrasound, sound waves are passed through the uterus and transformed into a picture on a television screen. An ultrasound can be used to:

• determine the gestation of the pregnancy.
• determine multiple pregnancies.
• check the development of the pregnancy’s spine (if at high risk of neural tube defect).
• check the pregnancy’s development, and determine if the pregnancy is at an increased risk for having a chromosomal problem.

An ultrasound can be performed at any time during a pregnancy and is usually done between 8-12 weeks to determine the number of fetuses, 11.5-13.5 weeks for nuchal translucency screening tests, and 18-20 weeks to check physical development.

Chorionic Villus Sampling (CVS)

Performed between the 11th and 12th week of pregnancy, the CVS test involves removal of cells from the placenta via a needle passed through the abdominal wall or vagina (depending on the location of the pregnancy). The test is performed to diagnose chromosomal problems such as Down syndrome. The risk of miscarriage following the procedure is between 1% and 2%.

Amniocentesis

Performed between the 15th and 19th week of pregnancy, the amnio test involves removal of amniotic fluid from the uterus via a needle passed through the abdomen under ultrasound guidance. The fluid removed contains cells shed by the pregnancy. These cells are then grown in a lab until there are enough to test for chromosomal or DNA abnormalities.

Summary

With all prenatal testing, it is important to remember that a normal test result cannot exclude every possible problem as not all birth defects can be detected by these tests. For more information on prenatal testing, contact:

Queensland Clinical Genetics Services
(07) 3636 1686
Prenatal testing and genetic counselling.

Mater Mother’s Hospital
(07) 3840 1593
Prenatal testing and genetic counselling.

Interstate services summary