What blood tests are done during pregnancy?
What blood tests are done during pregnancy?
ACOG lists a complete blood count, a blood type with Rh factor and tests for certain infections among the tests done early, and glucose screening, usually between 24 and 28 weeks, among those done later. Not every pregnancy test is a blood test, ACOG says: some use urine, and a group B strep test uses a swab. Screening for birth defects is a personal choice, ACOG says.
This is not clinical evidence and not medical advice. It does not replace your care team. Discuss anything here with your clinician before you act on it.
Arun Verma, co-founder of Triangle · Published · Updated
Some blood tests come early in pregnancy and some later, some are routine and some are your choice, and a panel can go by more than one name on a report.
What blood tests are done at the first prenatal visit?
MedlinePlus describes a prenatal panel as a group of blood tests done in the first trimester, often at the first prenatal visit, and gives obstetric panel and OB panel as other names for it, so a report may use either. MedlinePlus says the blood comes from a vein in your arm, the draw usually takes less than five minutes, and no special preparation is needed. NICHD's first-visit list covers a blood type and Rh factor, a blood count such as hemoglobin and hematocrit, and tests for infections such as rubella, hepatitis B and syphilis.
What do the blood count and the blood type tests measure?
MedlinePlus says the complete blood count (CBC) measures many parts of your blood, including red blood cells, white blood cells and platelets, and that the blood type test finds your type, A, B, AB or O, and checks your Rh factor. ACOG says the Rh factor is a protein on the surface of red blood cells, that with it you are Rh positive and without it you are Rh negative, and that the positive or negative in a blood type such as O positive refers to Rh status.
What do the infection tests look for?
MedlinePlus says the prenatal panel's tests check for diseases and infections that can affect the health of you and your developing baby, and that the rubella test shows whether you are immune, which you would be if you have been vaccinated against rubella or infected with it in the past. ACOG says everyone should be tested for hepatitis B and hepatitis C infection during pregnancy.
What blood tests come later?
Glucose screening is one of the later tests ACOG lists, usually between 24 and 28 weeks. It is a sugary drink followed by a blood test one hour later to measure blood sugar, and NICHD says it assesses your risk for gestational diabetes. ACOG says it might be done in the first trimester if you have risk factors for diabetes or had gestational diabetes in a past pregnancy. The one-hour screening can lead to a longer test. NICHD says a provider may order a glucose tolerance test if the first result is above a certain level, and that for it you fast beforehand, drink a sugary drink and have blood taken every hour for three hours. A fair question for your midwife or doctor is what the fasting instructions are.
Which blood tests are optional?
Screening for birth defects is a personal choice, ACOG says, and a screening test cannot tell whether the fetus actually has a birth defect. Screening tests do not diagnose problems, NICHD says. They evaluate risk, and diagnostic tests are a separate category. Several screening tests use a blood sample. NICHD's list includes the first trimester screen, the maternal serum screen and cell-free fetal DNA. A fair question for your midwife or doctor is which of these screening tests they offer.
Why might my list differ from someone else's?
Some tests are for everyone and others depend on you. NICHD says every woman has certain tests during pregnancy, and that some women, depending on age, family history or ethnicity, may undergo additional testing. The HHS Office on Women's Health lists the same kinds of factors: age, personal or family health history, ethnic background and the results of routine tests.
Can I compare blood test results from different labs?
Not directly. MedlinePlus says methods differ from lab to lab, which is why reference ranges often differ, and that results from different labs can't be compared. The range that applies to a result is the one listed on its own lab report. MedlinePlus adds that for trends over time it is important to try to stay with one lab. If your results came from two practices, you could ask whoever ordered each test which lab ran it.
What could I ask my midwife or doctor about these tests?
You could ask which tests are routine at your practice and which are your choice, and when each is usually done. The HHS Office on Women's Health says that learning about a test, why it is being suggested for you and what the results could mean can help with worries. If you have seen another practice, a fair question is whether they have your earlier results, and how you will receive new ones. NICHD says that if your provider orders a screening test, they can explain what the results mean and possible next steps.
Sources
- ACOG: Routine Tests During Pregnancy (FAQ133, last updated April 2024, last reviewed January 2026): ACOG says certain lab tests are part of routine care during pregnancy, some done with a blood sample and others with a urine sample or a sample of fluid taken from the vagina, cervix or rectum.
- ACOG: Routine Tests During Pregnancy (FAQ133, last updated April 2024, last reviewed January 2026): ACOG lists a complete blood count (CBC) and blood type and Rh factor among the routine lab tests done early in pregnancy, along with urinalysis and urine culture, and says pregnant women are also typically tested for specific diseases and infections early in pregnancy.
- ACOG: Routine Tests During Pregnancy (FAQ133, last updated April 2024, last reviewed January 2026): ACOG says the tests done later in pregnancy include glucose screening and group B streptococcus (GBS) screening; the GBS test is a swab sample from the vagina and rectum, not a blood test.
- ACOG: Routine Tests During Pregnancy (FAQ133, last updated April 2024, last reviewed January 2026): ACOG says screening and testing for birth defects are a personal choice.
- MedlinePlus: Prenatal Panel (last updated September 23, 2024): MedlinePlus says a prenatal panel is a group of blood tests done in early pregnancy, in the first trimester and often at the first prenatal visit, and gives other names for it: obstetric panel and OB panel.
- MedlinePlus: Prenatal Panel (last updated September 23, 2024): MedlinePlus says a prenatal panel needs a blood sample from a vein in the arm, usually takes less than five minutes, and needs no special preparation.
- NICHD: Pre-Pregnancy Care and Prenatal Care, section "The First Visit" (no review date shown on the page): NICHD's description of the first prenatal visit lists prenatal blood tests to determine blood type and Rh factor, do a blood count (for example hemoglobin and hematocrit), and test for infections such as rubella, hepatitis B and syphilis.
- MedlinePlus: Prenatal Panel (last updated September 23, 2024): MedlinePlus says a complete blood count measures many parts of the blood, including red blood cells, white blood cells and platelets.
- MedlinePlus: Prenatal Panel (last updated September 23, 2024): MedlinePlus says the blood type test finds out your blood type (A, B, AB or O) and checks your Rh factor, a type of protein on the surface of red blood cells.
- ACOG: Routine Tests During Pregnancy (FAQ133, last updated April 2024, last reviewed January 2026): ACOG says the Rh factor is a protein found on the surface of red blood cells: with the protein you are Rh positive, without it you are Rh negative, and the positive or negative part of a blood type such as O positive or A negative refers to Rh status.
- MedlinePlus: Prenatal Panel (last updated September 23, 2024): MedlinePlus says the prenatal panel's tests check for diseases and infections that can affect the health of you and your developing baby.
- MedlinePlus: Prenatal Panel (last updated September 23, 2024): MedlinePlus says the rubella test shows whether you are immune to rubella, and that you would be immune if you have been vaccinated against it or infected with it in the past.
- ACOG: Routine Tests During Pregnancy (FAQ133, last updated April 2024, last reviewed January 2026): ACOG says everyone should be tested for hepatitis B and hepatitis C infection during pregnancy.
- NICHD: What tests might I need during pregnancy? (last reviewed January 21, 2025): NICHD says glucose challenge screening is usually given between 24 and 28 weeks of pregnancy and involves consuming a sugary drink and getting a blood test 1 hour later to measure blood sugar levels.
- NICHD: What tests might I need during pregnancy? (last reviewed January 21, 2025): NICHD says glucose challenge screening assesses your risk for gestational diabetes.
- ACOG: Routine Tests During Pregnancy (FAQ133, last updated April 2024, last reviewed January 2026): ACOG says glucose screening usually is done between 24 and 28 weeks of pregnancy, and might be done in the first trimester of pregnancy if you have risk factors for diabetes or had gestational diabetes in a past pregnancy.
- NICHD: What tests might I need during pregnancy? (last reviewed January 21, 2025): NICHD says that if the 1-hour glucose challenge screening is above a certain level, a health care provider may order a glucose tolerance test, for which you fast and then drink a sugary drink and have blood taken every hour for 3 hours.
- NICHD: What tests might I need during pregnancy? (last reviewed January 21, 2025): NICHD says some prenatal tests are screening tests and others are diagnostic tests, and that screening tests do not diagnose problems but evaluate risk.
- ACOG: Routine Tests During Pregnancy (FAQ133, last updated April 2024, last reviewed January 2026): ACOG says a screening test cannot tell whether the fetus actually has a birth defect.
- NICHD: What tests might I need during pregnancy? (last reviewed January 21, 2025): NICHD lists the first trimester screen (blood drawn), the maternal serum screen (blood drawn, between 15 and 20 weeks) and cell-free fetal DNA (a noninvasive test using the mother's blood) among its screening tests for chromosomal and neural tube defects and other conditions.
- NICHD: What tests might I need during pregnancy? (last reviewed January 21, 2025): NICHD says every woman has certain tests during pregnancy and that some women, depending on age, family history or ethnicity, may undergo additional testing.
- HHS Office on Women's Health: Prenatal care and tests (page last updated September 26, 2025): HHS Office on Women's Health says some tests are suggested for all women and others might be offered based on age, personal or family health history, ethnic background and results of routine tests.
- MedlinePlus: How to Understand Your Lab Results (last updated September 4, 2025): MedlinePlus says labs often use different testing methods and so often use different reference ranges, that to compare a result with the normal range you check the reference range listed on your lab report, and that you can't compare results from different labs.
- MedlinePlus: How to Understand Your Lab Results (last updated September 4, 2025): MedlinePlus says that if you're looking for trends in your test results over time, it's important to try to use the same lab for testing.
- HHS Office on Women's Health: Prenatal care and tests (page last updated September 26, 2025): HHS Office on Women's Health says that if your doctor suggests certain prenatal tests, you can ask lots of questions, and that learning about the test, why it is being suggested for you and what the results could mean can help you cope with worries.
- NICHD: What tests might I need during pregnancy? (last reviewed January 21, 2025): NICHD says that if a health care provider orders a screening test, the provider can explain what the test results mean and possible next steps.
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