Prenatal Genetic Testing

Prenatal genetic testing is the testing that is done on a pregnant woman to help measure the health of the fetus. There are various tests that are performed in various stages of pregnancy. These tests and their time of occurrence are discussed in this article.

Prenatal Genetic Testing:

First Trimester

In the first trimester, there are basically two tests that can be performed on a pregnant woman. One is a blood test on the mother that determines the levels of various hormones in the blood among other things. The second test is an ultrasound, in which the scanning of the developing fetus is done to ensure its proper growth inside the uterus.

Second Trimester

In the second trimester of pregnancy, there are more tests that can be performed. The most important among these is the test for alpha – fetoprotein (AFP screening). The blood test determines the levels of AFP in the blood of the mother. AFP is a protein which is required for the development of the fetus’ liver and is present in the amniotic sac of the uterus. This test is known as Maternal serum AFP. Abnormal levels of this fluid indicate a risk of abnormalities such as:

  • Defect in the abdominal wall of the fetus
  • Presence of twins in the uterus
  • A miscalculated due date of delivery
  • Down Syndrome
  • Defects of open neural tubes such as spina bifida

Some Other Types of Prenatal Genetic Testing:

Other prenatal genetic tests include:


This test is performed to diagnose the presence of chromosomal disorders and open neural tube defects. Unfortunately, this test comes with a risk of miscarriage. But in high-risk pregnancies, some parents prefer to know in advance if there will be any defects their child will have.

Chronic Villus Sampling

In this prenatal test, some cells are removed from the placenta for genetic testing. The placenta cells can carry some genes of the fetus and therefore be used as a way to predict if the fetus will have the same genes.

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