Prenatal tests help evaluate the health of both mother and child. They provide important information to help guide healthcare decisions while pregnant and once your child is born. Many of these tests are standard, however special tests may be ordered by your provider. It is important to review the results of all tests with your care team, to better understand what they mean.
Prenatal tests for mothers
While you are pregnant, your health affects your baby’s health. Your physician may order certain tests in your first, second or third trimester to better care for both you and your child while pregnant. Some tests are routine, while others may be recommended for mothers with certain risk factors.
Routine prenatal tests for mothers commonly include:
- Anemia/Iron deficiency – Iron helps oxygen get to your organs and to your baby. Mild anemia isn’t unusual during pregnancy but should be treated. Severe anemia can cause low birth weight, premature birth and could endanger mother and baby.
- Genetic evaluation – This test is done on both parents to see if you carry genes for any genetic disorders. It helps you know what the chances are of passing that disorder to your baby. This test can be done before you get pregnant or while you are pregnant. Learn more.
- Hepatitis B – Is a serious liver infection, this condition can be passed to a baby in womb and could cause life threatening issues. It is important to test pregnant mothers for Hepatitis B as certain medications, when taken by a mother during pregnancy, can improve outcomes for babies. If a mother is infected, vaccinating the baby right after birth, may also prevent the baby from becoming infected.
- Hepatitis C – Is a virus that can cause liver disease. There’s no vaccination for it, but it’s rare for a mother to pass it to her baby. If you’re infected, your baby will be tested at around 18 months. Currently, there’s no Hepatitis C treatment that’s safe during pregnancy.
- Human immunodeficiency virus (HIV) – A mother with HIV can pass it to her unborn baby. Taking HIV medications during pregnancy, giving the baby HIV medications for four to six weeks after birth, C-section delivery and formula feeding instead of nursing can all reduce the baby’s risk of getting HIV.
- Rh or Rhesus factor – This is a protein some people have in their blood. If you don’t have it and your baby does, your body may react as if it were allergic to the baby. There is an important injection that can be taken to keep your baby from getting very sick.
- Rubella/German Measles – The MMR vaccine has mostly eliminated Rubella in the United States, but someone who isn’t vaccinated can still catch it, particularly when travelling outside the U.S. Although symptoms are generally mild, passing it on to a developing fetus can cause a range of severe birth defects, including deafness, heart defects and developmental disabilities. There is no treatment for Rubella.
- Sexually transmitted infections – If a pregnant woman has chlamydia, gonorrhea or herpes, it can be passed to the baby during birth. It’s important to test for and treat these diseases prior to delivery.
- Tuberculosis (TB) – This is a bacterial infection in the lungs that can become deadly without treatment. It can be passed onto an unborn baby and cause low birthweight. TB can be treated during pregnancy, so it is important to get tested.
- Group B streptococci (GBS) – Is a bacterium that can be passed to a baby during birth. It is fairly common and usually does not cause severe problems, but if detected, antibiotics can be given during labor to protect the baby.
- Gestational diabetes – Is a condition where pregnancy causes your body to have higher blood sugar. A glucose test is generally done between weeks 24 and 28 of pregnancy, although with certain risk factors it may be done earlier. If you are diagnosed with gestational diabetes, it is important to keep you sugars regulated throughout your pregnancy. This will be done by using specific meal plans, physical activity and potentially medication or insulin injections. If gestational diabetes is uncontrolled, your baby could have risk factors such as high birth weight, early delivery, breathing difficulty, low blood sugar and increased chance of developing type 2 diabetes. Most often gestational diabetes goes away when you are no longer pregnant.
- Preeclampsia –This generally develops later in pregnancy, after week 20. Symptoms may include high blood pressure, protein in the urine, swelling, sudden weigh gain, headaches and changes in vision. Preeclampsia can lead to dangerous seizures in the mother. And it can cause premature delivery or restriction of food and oxygen to the baby. The cure is delivery. But it can be treated with medications to help prolong the pregnancy safely.
Baby’s health – tests during pregnancy
During your pregnancy, your doctor may recommend various tests that provide insight into your baby’s health. One helpful test measures Alpha fetoprotein (AFP), which is produced by the baby’s liver and is present in the mother’s blood. AFP can help determine:
- Due date – AFP levels change during pregnancy
- Multiple births – more babies produce higher levels of AFP
- Risk of a genetic disorder like Down syndrome
- Risk of a birth defect like neural tube defect, which can affect the development of the baby’s spine and brain
Ultrasound uses sound waves to get a picture of your baby. It’s safe and non-invasive. You’ll likely have at least one ultrasound during pregnancy, but some women may have more. Ultrasound can be used to:
- Confirm your pregnancy
- Determine your due date
- Let you know if you’re expecting more than one baby Evaluate the baby’s growth
- Determine gender
- Examine the placenta and amniotic fluid
- Screen for birth defects
- Guide a needle for tests that require a needle to be inserted into the uterus
- See how baby is positioned before delivery
This test uses a needle to remove some of the amniotic fluid surrounding the baby. Generally, it’s only done when there’s a reason to believe the baby may be at a higher risk of illness or birth defect. It might be done if:
- There’s a history of a genetic condition in your family
- You or your partner are carriers of a genetic condition
- You were previously pregnant with a baby that had a genetic disorder
- Your ultrasound showed a possible illness or birth defect
- You’re 35 or older
- You have too much amniotic fluid
- You need to consider an early delivery and must know if the baby’s lungs are ready
Chorionic villus sampling
The placenta shares the baby’s genetic makeup and can be tested. It’s generally done between 10 and 13 weeks of pregnancy. It carries some risks, but it’s the earliest testing that can confirm a genetic condition.
If you have questions or concerns about which tests you should have before and during pregnancy, speak with your doctor. They can help you understand which tests you may want to consider and why. With all tests, you’ll want to talk to your doctor about what the results mean and whether to do follow-up testing.