Diagnostic Tests

When there is a concern about the health of the fetus, the following diagnostic tests may be used.

Amniocentesis

Amniocentesis is a procedure that takes a sample of the amniotic fluid surrounding the fetus. It is an accurate way to check for chromosomal abnormalities. Amniocentesis is offered to women who are considered high-risk, for example, a woman who is over 35 years of age, has a close family member who has a genetic problem, or has an abnormal screening test for Down syndrome. The test is usually done between a woman’s 15th and 18th weeks of pregnancy. Ultrasound is used to guide a thin needle through the wall of the uterus and into the amniotic fluid without touching the fetus. You will be asked to rest and take it easy the day after the procedure.

Amniocentesis is done when the benefits of knowing about a birth defect or disease are seen to outweigh the risk. The chance of miscarriage after amniocentesis is estimated to be 1 in 200. There is also a small risk of puncturing the placenta or causing an infection.

Although most women have some cramping following the procedure, you should call your caregiver immediately if you have severe cramps or if you observe vaginal bleeding or fluid discharge following the amniocentesis.

Fetal Surveillance

Fetal surveillance means evaluating the current health of the fetus. Simple forms of fetal surveillance including having your caregiver listen to the fetal heartbeat with a stethoscope or observing how often you feel kicking. If there are concerns about the health of your pregnancy, more extensive surveillance can be done.

Non-Stress Test

A non-stress test may be suggested if you have not felt kicking or if you are past your due date. A non-stress test uses an electronic heart monitor to measure the fetal heart patterns.

Biophysical Profile (BPP)

A biophysical profile combines information from a non-stress test and from an ultrasound. A biophysical profile measures five aspects of fetal health:

• breathing movements
• body movements
• muscle tone
• the amount of amniotic fluid around your baby
• fetal heart patterns

A score out of a total of 10 points is given – two points for each area.

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