What Prenatal Tests and Screenings Are Offered at a Birth Center?

Author: Igel Cudiera

Some families wonder whether choosing a birth center means having fewer tests. The prenatal screening recommendations from groups such as the American College of Obstetricians and Gynecologists (ACOG), the Centers for Disease Control and Prevention (CDC), and the U.S. Preventive Services Task Force (USPSTF) are written for pregnant people in general. This guide covers common prenatal testing, what each test looks for, when it usually happens, and how testing works at Birthing Center NYC. For the rhythm of the visits themselves, see what to expect at your prenatal appointments.

Key Takeaways

• Screening tests estimate the chance of a condition. Diagnostic tests show whether a condition is actually present.
• Some tests are recommended for everyone who is pregnant, some depend on your health history or risk factors, and some, such as genetic screening, are your choice.
• Early pregnancy usually brings blood tests, urine tests, and infection screening. Later pregnancy brings gestational diabetes screening and group B strep testing.
• New York law requires practitioners caring for pregnant people to order syphilis and hepatitis B testing, and New York requires prenatal care settings to recommend HIV testing.
• At Birthing Center NYC, bloodwork is collected in the office and sent to a lab that is in-network with your insurance, and ultrasounds are referred to an in-network provider.
• ACOG states that informed consent for testing includes an explanation of the risks and benefits of having or declining a test, so you can ask questions about any test before you decide.

What Is the Difference Between Screening and Diagnostic Tests?

Prenatal tests fall into two broad groups, and knowing which kind you are having makes the results easier to understand. ACOG explains that screening tests can tell you the chances that your fetus has certain conditions, while diagnostic tests can tell you whether your fetus actually has certain disorders.

• Screening tests estimate risk. ACOG notes that a positive screening result does not mean that your fetus definitely has the disorder, and a negative result means your fetus is at lower risk, not that the condition is ruled out.
• Diagnostic tests look for the condition itself. For genetic conditions, ACOG explains that these tests are done on cells from the fetus or placenta, obtained through amniocentesis or chorionic villus sampling (CVS).

The word "screening" is also used for routine checks that have nothing to do with genetics. These can also lead to follow-up testing. For example, ACOG notes that if your glucose screening result is high, you should have another type of glucose test to confirm the results.

Which Tests Are Commonly Done Early in Pregnancy?

ACOG lists several routine lab tests that are done early in pregnancy: a complete blood count, blood type and Rh factor, a urinalysis, and a urine culture. Pregnant people are also typically tested early for certain infections.

Blood Tests

• Complete blood count (CBC). This counts the different types of cells in your blood. ACOG notes that the number of red blood cells can show whether you have a certain type of anemia.
• Blood type and Rh factor. This sample is usually taken during the first prenatal visit. If you are Rh negative, an antibody screen can show whether you have made antibodies to Rh-positive blood, and ACOG notes you may have this test again at 28 weeks.
• Rubella. ACOG explains that your blood can show whether you have been infected with rubella or vaccinated against it.

Urine Tests

• Urinalysis. This looks at what is in your urine. ACOG notes, for example, that high protein levels may signal kidney disease or preeclampsia, a serious complication that can occur later in pregnancy or after birth.
• Urine culture. This looks for bacteria in your urine, which can be a sign of a urinary tract infection. ACOG explains that the test is done because sometimes these infections do not cause symptoms, and the USPSTF recommends screening pregnant people for bacteria in the urine using a urine culture.

Infection Screening

The CDC recommends that all pregnant women get tested for HIV, hepatitis B, hepatitis C, and syphilis during each pregnancy. The USPSTF also recommends HIV screening for all pregnant persons, hepatitis B screening at the first prenatal visit, and early, universal screening for syphilis during pregnancy.

• Syphilis. ACOG states that you should be tested three times during pregnancy: at your first prenatal visit, in the third trimester, and at delivery.
• Chlamydia and gonorrhea. ACOG recommends testing if you are under age 25 or at increased risk for sexually transmitted infections.
• Tuberculosis (TB). ACOG states that people who are at high risk of TB should be tested for it.

What Is Checked at Every Prenatal Visit?

• Blood pressure. The USPSTF recommends screening for hypertensive disorders of pregnancy, a group of conditions that includes preeclampsia, with blood pressure measurements at each prenatal care visit throughout pregnancy.
• Your mood and emotional health. The USPSTF recommends screening for depression in adults, including pregnant and postpartum persons. ACOG explains that your provider may ask questions about your mood or ask you to fill out a short survey that screens for mental health conditions.

Do You Have Ultrasounds During Birth Center Prenatal Care?

ACOG states that you should have at least one standard ultrasound exam during pregnancy, usually at 18 to 22 weeks. ACOG notes that an ultrasound between 18 and 22 weeks checks for major physical defects in the brain and spine, facial features, abdomen, heart, and limbs.

Some people also have an ultrasound in the first trimester. ACOG explains that an early ultrasound can be used to estimate gestational age, help screen for certain genetic disorders, count the number of fetuses, and check the fetal heart rate, and that a first-trimester ultrasound is not standard for everyone.

Do midwives do ultrasounds? The American College of Nurse-Midwives (ACNM) describes certified nurse-midwives and certified midwives as able to order and interpret laboratory and diagnostic tests. Where the scan itself happens depends on the practice. At Birthing Center NYC, the practice's insurance page states that ultrasounds are referred to an in-network provider.

What Genetic Screening and Testing Is Available?

ACOG states that both screening and diagnostic genetic testing are offered to all pregnant women, and that whether to have prenatal testing is your choice. Your personal beliefs and values matter here. ACOG notes that you can choose screening tests, diagnostic tests, both, or no testing at all, and that there is no right or wrong answer.

Genetic Screening Tests

• Cell-free DNA screening. This blood test screens for certain chromosome conditions. ACOG states that it can be done starting at 10 weeks of pregnancy and that results take about 1 week.
• First-trimester screening. This combines a blood test with an ultrasound that measures the thickness of a space at the back of the fetus's neck, called nuchal translucency. ACOG notes that both are usually done between 10 and 13 weeks.
• Second-trimester screening (quad screen). ACOG explains that this blood test screens for Down syndrome, trisomy 18, and neural tube defects, and is done between 15 and 22 weeks.

Carrier Screening

Carrier screening is a different kind of genetic test. ACOG explains that it can tell you whether you carry a gene for certain genetic disorders. It is offered to everyone who is pregnant or thinking about pregnancy for cystic fibrosis, hemoglobinopathies (inherited blood disorders), and spinal muscular atrophy, and it uses a sample of blood, saliva, or tissue from inside the cheek. ACOG is clear that carrier screening is your choice.

Diagnostic Genetic Tests

• Chorionic villus sampling (CVS). ACOG states that CVS is done between 10 and 13 weeks of pregnancy.
• Amniocentesis. ACOG states that it is usually done between 15 and 20 weeks but can be done up until birth, and that there is a very small chance of pregnancy loss with the procedure. ACOG notes that the chance of miscarriage with CVS is slightly higher than with amniocentesis.

ACOG also notes that you can choose diagnostic tests instead of, or in addition to, screening tests.

Which Tests Happen Later in Pregnancy?

Gestational Diabetes Screening

ACOG states that all pregnant women should be screened for gestational diabetes. If you have risk factors, your blood sugar may be tested early in pregnancy. Otherwise, ACOG says it is measured between 24 and 28 weeks, and the USPSTF recommends screening at 24 weeks of pregnancy or after. For the common screening test, ACOG explains that you drink a special sugar mixture and a blood sample is taken an hour later.

Rh Immunoglobulin for Rh-Negative Pregnancies

If your blood is Rh negative, ACOG explains that Rh immunoglobulin given at 28 weeks of pregnancy helps prevent your body from making antibodies against Rh-positive blood cells. It is given again within 72 hours after the birth of an Rh-positive baby.

Group B Strep Testing

Group B streptococcus (GBS) is a type of bacteria that, as ACOG explains, can pass to a baby during labor, although this is rare. ACOG recommends GBS screening for all pregnant people between 36 0/7 and 37 6/7 weeks of pregnancy, that is, from the start of week 36 through the end of week 37. The test uses a swab from the vagina and rectum.

Repeat Infection Testing

Some infection testing is repeated later in pregnancy. Syphilis testing is repeated in the third trimester, as described above. The CDC recommends third-trimester chlamydia testing for people under 25 or at continued high risk, and third-trimester gonorrhea testing for people with ongoing risk factors. New York's HIV testing guideline also calls for repeat HIV testing before 36 weeks, preferably between 28 and 32 weeks, for anyone whose earlier test was negative or not documented.

What Prenatal Testing Does New York Require?

New York has its own rules for some prenatal tests. These describe what practitioners must order or offer.

• Syphilis. New York Public Health Law Section 2308 requires practitioners attending a pregnant person to take a blood sample for a syphilis test at the first examination and to order a syphilis test during the third trimester. The New York State Department of Health states that pregnant people should be screened at least three times during each pregnancy: at the first examination, during the third trimester, and again at delivery.
• Hepatitis B. Under New York Public Health Law Section 2500-e, the blood sample taken for syphilis testing must also be sent for hepatitis B surface antigen testing.
• HIV. The New York State Department of Health AIDS Institute's clinical guideline states that state law requires all prenatal care settings regulated by the Department of Health, including birthing centers, to provide information about HIV and recommend HIV testing, preferably at the first prenatal visit.

Which Tests Are Routine and Which Depend on Your History?

Not every test applies to every pregnancy. Based on the guidance above, prenatal tests generally fall into three groups:

• Recommended for everyone who is pregnant: blood type and Rh factor, a complete blood count, a urine culture, testing for HIV, hepatitis B, hepatitis C, and syphilis, blood pressure checks, depression screening, gestational diabetes screening, and group B strep testing.
• Based on your history or risk factors: chlamydia and gonorrhea testing for people under 25 or at increased risk, TB testing for people at high risk, earlier blood sugar testing for people with risk factors for gestational diabetes, and an antibody screen and Rh immunoglobulin for people who are Rh negative.
• Your choice: genetic screening, carrier screening, and diagnostic genetic testing.

Your midwife can talk with you about whether any other tests make sense for you based on your health history or how your pregnancy is going.

What Happens If a Screening Result Is Abnormal?

An abnormal or higher-risk screening result is a reason for a closer look, not a diagnosis on its own. What comes next depends on the test:

• Genetic screening. ACOG explains that a positive screening result does not mean the fetus definitely has the condition, and that a positive cell-free DNA result should be followed by a diagnostic test with amniocentesis or CVS if you want a definite answer. A genetic counselor or another health care professional can explain what the results mean and help you decide on next steps.
• Glucose screening. ACOG notes that a high result should be followed by another type of glucose test to confirm it.
• Group B strep. ACOG recommends antibiotics during labor for people whose GBS culture is positive, unless a cesarean birth is performed before labor begins and before the water breaks.

Birthing Center NYC describes birth center care as an option for women whose pregnancies meet the screening criteria. Your prenatal care provider can explain what a specific result means for your care. You can read more about who is a candidate for birth center care.

How Does Prenatal Testing Work at Birthing Center NYC?

Here is what Birthing Center NYC says about testing on its own website:

• The practice states that all aspects of evidence-based prenatal care and testing are offered to clients during clinical visits.
• The homepage lists bloodwork, genetic screening, and ultrasound as part of routine care.
• The insurance page explains that bloodwork is collected in the office and sent to a lab that is in-network with your insurance, and that ultrasounds are referred to an in-network provider.
• Prenatal visits are scheduled monthly until 28 weeks, every 2 to 3 weeks until 36 weeks, and then weekly until birth.

The website does not list which individual tests take place in the office. Depending on the test, testing may be performed through the birth center, an outside laboratory, an imaging provider, or another healthcare provider, so ask your midwife where each test you are offered will be done. You can learn more about our midwifery services. Because lab work and ultrasounds involve outside providers, it is also worth taking a moment to check your coverage. Our guide to how insurance works for birth center care lists questions to ask your insurer.

Can You Decline Prenatal Tests?

Yes. ACOG states that informed consent for any patient testing requires an explanation of risks and benefits, including those associated with declining the test, and that an adult patient with decision-making capacity has the right to refuse treatment, including during pregnancy. ACOG also notes that counseling about more routine tests, such as HIV testing during prenatal care, should include the fact that certain tests are standard. For genetic screening and carrier screening, ACOG describes testing as your choice.

Birthing Center NYC states that clients can decline certain tests if they wish, and that the practice uses a shared decision-making model when midwife and client discuss testing options. You can read more about how shared decision making works here. Because New York requires practitioners to order some tests, such as syphilis and hepatitis B testing, bring any questions about a specific test to your midwife.

Questions to Ask Your Midwife About Prenatal Testing

1. Which tests do you recommend for me, and why?
2. Is this a screening test or a diagnostic test?
3. When in my pregnancy will this test happen?
4. Where will it be done: in the office, at an outside lab, or with an imaging provider?
5. How and when will I get my results?
6. What happens if a result is abnormal or higher risk?
7. Which tests are optional, and what would declining mean for my care?
8. Could a result change whether birth center care is still the right fit?
9. Will my insurance cover this test, and who will bill me for it?
10. Should I talk with a genetic counselor before deciding on genetic screening?

Frequently Asked Questions

Do midwives do ultrasounds?

ACNM describes certified nurse-midwives and certified midwives as able to order and interpret laboratory and diagnostic tests. Where the ultrasound is performed depends on the practice. At Birthing Center NYC, ultrasounds are referred to an in-network provider.

Will I have the same tests at a birth center as with an OB?

The prenatal testing recommendations from ACOG, the CDC, and the USPSTF are written for pregnancy in general, not for a specific setting. Birthing Center NYC states that all aspects of evidence-based prenatal care and testing are offered during clinical visits. Your midwife can tell you which tests apply to your pregnancy.

Is genetic screening required?

No. ACOG states that genetic screening and diagnostic testing are offered to all pregnant women and that whether to have them is your choice. Some people decide not to have any genetic testing.

Do I need bloodwork at every prenatal visit?

The guidance described above ties most prenatal blood tests to particular points in pregnancy, such as the early lab work, gestational diabetes screening at 24 to 28 weeks, and repeat infection testing in the third trimester. Blood pressure, by contrast, is checked at every visit. Your prenatal care provider can tell you which tests to expect at each visit.

How long do genetic screening results take?

It depends on the test. ACOG states that cell-free DNA results take about 1 week. Ask your midwife about the timing for any other test you are offered.

Talk With Our Midwifery Team

Prenatal testing is easier to navigate when you know what each test is for and feel free to ask questions. Bring this list to your next prenatal visit, or schedule a consultation if you are still exploring your options.

Sources and References

• Prenatal Genetic Screening Tests, Prenatal Genetic Diagnostic Tests, and Carrier Screening. American College of Obstetricians and Gynecologists.
• Routine Tests During Pregnancy. American College of Obstetricians and Gynecologists.
• The Rh Factor: How It Can Affect Your Pregnancy. American College of Obstetricians and Gynecologists.
• Gestational Diabetes. American College of Obstetricians and Gynecologists.
• Group B Strep and Pregnancy. American College of Obstetricians and Gynecologists.
• Prevention of Group B Streptococcal Early-Onset Disease in Newborns, Committee Opinion No. 797. American College of Obstetricians and Gynecologists.
• Ultrasound Exams. American College of Obstetricians and Gynecologists.
• Depression During Pregnancy. American College of Obstetricians and Gynecologists.
• Informed Consent and Shared Decision Making in Obstetrics and Gynecology, Committee Opinion No. 819. American College of Obstetricians and Gynecologists.
• Screening and Testing for HIV, Viral Hepatitis, STD and Tuberculosis in Pregnancy. Centers for Disease Control and Prevention.
• Syphilis Infection During Pregnancy: Screening, Hepatitis B Virus Infection in Pregnant Women: Screening, and HIV Infection: Screening. U.S. Preventive Services Task Force.
• Asymptomatic Bacteriuria in Adults: Screening, Gestational Diabetes: Screening, Hypertensive Disorders of Pregnancy: Screening, and Depression and Suicide Risk in Adults: Screening. U.S. Preventive Services Task Force.
• Public Health Law Section 2308 and Public Health Law Section 2500-e. New York State Senate.
• Congenital Syphilis: Information for Providers and Perinatal Hepatitis B Prevention Program. New York State Department of Health.
• HIV Testing During Pregnancy and at Delivery. New York State Department of Health AIDS Institute.
• Definition of Midwifery and Scope of Practice of Certified Nurse-Midwives and Certified Midwives. American College of Nurse-Midwives.

About the Author

Igel Cudiera

Igel Cudiera wrote this article for Birthing Center NYC. It draws on guidance from the American College of Obstetricians and Gynecologists, the Centers for Disease Control and Prevention, the U.S. Preventive Services Task Force, the New York State Department of Health, and the other sources listed above.

This content is intended for educational purposes only and does not replace personalized medical advice from a qualified healthcare provider. Every pregnancy is different, so talk with your midwife or prenatal care provider about which tests are recommended for you.