prenatal testing by trimester

Prenatal Testing By Trimester

While you are pregnant, you regularly visit a doctor to check up on your health and your child’s health. A significant part of these visits involves prenatal testing. But what exactly are prenatal tests and when should you expect them? Continue reading to learn more about prenatal testing by trimester.

What Are Prenatal Tests?

Prenatal tests are tests that are done during pregnancy to check up on a woman’s health along with her growing child’s health. states that these tests, “can detect conditions that can put a baby at risk for problems like preterm birth if they’re not treated. Tests also can help health care providers find things like a birth defect or a chromosomal abnormality.”

There are two main types of prenatal tests, screening and diagnostic tests. Screening tests are done to get information on the risk of whether a condition might be present. Diagnostic tests are typically done after screenings to determine with 100% accuracy whether these conditions are present. A diagnostic test will usually be performed after a screening test if the screening test comes back positive.

Prenatal Testing By Trimester

Testing is done several times throughout pregnancy to check up on the health of you and your growing baby. Certain tests are done at certain times because of the stages in the baby’s growth and some tests are even repeated each trimester.

Throughout your pregnancy, there are some routine tests that will likely be done at every doctors visit.  These may include a urine test, weight test, and a blood pressure test as well as others. Here is a list by trimester of additional testing that may be done.

First Trimester Testing

First-trimester testing, also known as first-trimester screening,  is done between 11 and 14 weeks of pregnancy. It is one test that consists of two parts. This test will include:

  • A blood test that measures the levels of two pregnancy-specific substances in the mother’s blood. These are pregnancy-associated plasma protein-A (PAPP-A), and human chorionic gonadotropin (HCG).
  • The other portion of this test is an ultrasound exam that measures the size of the clear space in the tissue at the back of the baby’s neck.

The Mayo Clinic states that “Using your age, the results of the blood test, and the ultrasound, your health care provider can gauge your risk of carrying a baby with Down Syndrome or trisomy 18 .”

Second Trimester Testing

The second trimester will bring many more tests to help your health care provider determine if your baby will be healthy. Along with the routine tests, you should expect:

  • Multiple Marker Test: This is a blood test that is done between week 15 and week 20 of your pregnancy. It is used to screen for neural tube defects and chromosomal disorders. also states that “This test can be combined with the first-trimester screening tests to give more accurate results.”
  • Ultrasound: Second-trimester ultrasounds, often called level 2 ultrasounds, are done between the 18th and 20th weeks of pregnancy. It is used by doctors to confirm that the baby is developing normally. If they haven’t already, this ultrasound can also determine the gender of the baby.
  • Glucose Screening: This test checks for gestational diabetes. This is a short-term form of diabetes that develops in some women while they are pregnant. If it is not diagnosed or treated, this can cause health problems for the baby. It is usually done around 24 to 28 weeks of pregnancy.

Third Trimester Testing

When you reach your third trimester, you will be offered more tests depending on your age, family history, health, and other things. Some new tests include:

  • Third-Trimester Ultrasound: An ultrasound in the third trimester can examine the placenta and can see if the baby is getting enough oxygen. If you have a high-risk pregnancy, you may have multiple ultrasounds in the third trimester.
  • Nonstress Test: This test is done when your doctor wants to check up on the health of the fetus. This will happen if you have a high-risk pregnancy or have already passed your due date. It checks if the baby responds normally to stimulation. A baby that does not respond might not be in danger, however, more testing could be needed.
  • Contraction Stress Test: According to Michigan Medicine of Michigan University, “A contraction stress test checks to see if your baby will stay healthy during contractions when you are in labor.” This test will usually take place around 34 or more weeks pregnant.


When it comes to prenatal testing by trimester, there are many different prenatal tests that all can be used to determine the health of your baby, and your health while you are pregnant. Knowing prenatal testing by trimester can help you know what to expect when the time comes. It is also important to remember that this is not a comprehensive list and your doctor may have you take more tests depending on your personal pregnancy. If you have any questions about a prenatal test, you should talk to your doctor to learn more. One way to help ensure that you are healthy is to exercise. Check out one of our previous articles for a Guide To Exercising When Pregnant.