Third Trimester Lab Tests: What They Check and Why They Matter
Third trimester lab tests are a crucial part of prenatal care. They help identify conditions that could affect you or your baby before delivery.
In most cases, these tests are routine screenings. They are performed to ensure safety, not because something is wrong.
What Are Third Trimester Lab Tests?
Third trimester lab tests include blood work, urine analysis, and infection screening performed between week 24 and birth.
They may include:
- Complete blood count
- Glucose tolerance test
- Urine analysis
- Antibody screening
- Group B Strep test
The goal is early detection and prevention.
What Exactly Do Doctors Check?
Complete Blood Count
This test evaluates:
- Hemoglobin levels
- Iron stores
- Signs of inflammation
Mild anemia is common in late pregnancy due to increased blood volume.
Glucose Tolerance Test
This third trimester lab test screens for gestational diabetes.
Process:
- Fasting blood sample
- Drinking a glucose solution
- Follow up blood samples
Gestational diabetes is often symptom free, which makes screening essential.
Urine Testing
Urine is checked for:
- Protein
- Glucose
Protein in urine may indicate preeclampsia.
Group B Strep Screening
Performed at 35 to 37 weeks.
If positive, antibiotics during labor protect the baby.
Medical Background Explained Simply
During the third trimester:
- Blood volume increases significantly
- Insulin resistance rises
- Placental hormones peak
These are normal physiological changes. However, in some women, they may contribute to complications.
That is why third trimester lab tests are so important.
Practical Example
Imagine a pregnant woman whose third trimester lab tests show mild anemia.
Symptoms may include:
- Fatigue
- Dizziness
- Weakness
Treatment may involve:
- Iron supplementation
- Dietary adjustments
- Follow up testing
When detected early, it is easy to manage.
Possible Risks Identified by Testing
Abnormal results may reveal:
- Gestational diabetes
- Significant anemia
- Preeclampsia indicators
- Infection
Untreated conditions may increase risks during delivery.
When to Call Your Doctor Immediately
Regardless of lab results, seek care if you experience:
- Severe headache
- Visual changes
- Sudden swelling
- High blood pressure
- Decreased fetal movement
Trust your instincts.
How to Prepare
- Follow fasting instructions
- Stay hydrated
- Write down questions
- Try not to anticipate worst case scenarios
These tests are preventive tools.
A Reassuring Perspective
Third trimester lab tests exist to protect you and your baby.
Most results are normal. If something requires attention, early action makes a significant difference.
You are not being tested because something is wrong. You are being supported.
For more practical, evidence based pregnancy guidance, explore additional in depth resources designed to help you feel confident and informed.