Antenatal Testing

What is Antenatal Testing? It refers to procedures during pregnancy that detect health problems in a growing fetus. It also diagnoses material conditions and establishes characteristics such as fetal sex, weight or age.

When To Test

 Pregnant woman may undergo antenatal testing during weeks 1-12 (first trimester), weeks 13-26 (second trimester), or weeks 27-40+ (third trimester). The time of the testing is dependent namely on the stage of pregnancy, medical history, and the health or age of the mother.

Types of Tests

There are two distinct types. Screening Tests These will suggest the possibility of a birth defect or genetic disorder. Diagnostic Tests Are more invasive, but they will determine is a fetus is going to be born with a certain condition. An example would be an amniocentesis to verify down syndrome. Routine Urine/Blood Tests At each pre-natal visit a pregnant woman has her urine tested to screen for possible disorders or infections. Blood tests are also ordered but not as frequently. The idea is to intervene before a problem escalates. Some conditions that doctors are looking for are: Anemia If a blood test indicates low hemoglobin, an iron supplement or injection may be suggested for the mother.


This can be treated with antibiotics, and if not detected it can be transmitted to the fetus, often resulting in death of the fetus.

Rh Factor

This is when a pregnant woman’s blood lacks a blood protein called the Rh factor, and the mom is labelled Rh negative. If the mom is carrying a baby with positive blood, complications may arise. By giving the mother a shot called Rh immune globulin at 28 weeks, the fetus will be protected. Another shot is also given after the delivery.

German Measles

If a pregnant woman contracts german measles her fetus can be seriously affected with heart defects, blindness and deafness.


HIV can be transmitted from mom to baby but treatment greatly reduces the risk.

GBS (Group Beta Strep)

This bacteria is often found in the vagina and rectum with no symptoms. If the newborn contracts it, serious complications can arise, such as pneumonia, blindness, deafness and possible death. Antibiotics are administered just prior to delivery with an infected mother. Triple Screen Is used to determine if a fetus has a higher chance of having certain congenital abnormalities. This test is highly inaccurate, but is used to determine if further testing is required.


By recording sound waves and producing the image of the fetus on a computerized screen, a technician is able to ‘see’ any obvious abnormalities. They can also determine the age of the fetus, check for twins and listen to the heartbeat. In early pregnancy a full bladder is required and the ultrasound is often used to determine a due date. Just before delivery it is often used to determine the position of the baby.


This is more risky, where a long needle is inserted into the sac surrounding the fetus, to draw a sample of amniotic fluid for further testing. It can diagnose more abnormalities and the maturity level of the lungs for a possible premature baby.

Chorionic Villus Sampling

During 10-12 weeks small samples of cells from the placenta are gathered either with a needle through the abdomen or a catheter through the cervix. These cells are observed for genetic abnormalities.

These antenatal tests are optional for the mother,as there are risks involved with most of them. But by using these procedures, one can ensure the best possible care for their baby if some complication should exist or develop. The lives of many babies have been greatly improved through prevention and early treatment with information gathered from these tests.