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Tests in pregnancy, week by week

The routine tests and scans the sources describe from early pregnancy to the third trimester, what each looks for, and what a result does and does not mean.

Screening tests and diagnostic tests

  • MedlinePlus says prenatal testing gives information about the health of the fetus before birth.1
  • MedlinePlus also says some routine tests during pregnancy check the pregnant person's health.1
  • MedlinePlus says screening tests look at risk and do not diagnose problems.2
  • An abnormal screening result does not mean there is a problem, MedlinePlus says.3
  • MedlinePlus says an abnormal result means more information is needed, and diagnostic testing may follow.3, 4
  • MedlinePlus says diagnostic tests help determine whether the pregnant person or the fetus has a certain health problem.5
  • MedlinePlus says some tests are suggested for all women, such as screenings for gestational diabetes, Down syndrome and HIV.6
  • MedlinePlus says a provider might offer other tests based on age, personal or family medical history, ethnic background and routine test results.7
  • MedlinePlus says it is the person's choice whether to have prenatal tests.8
  • MedlinePlus says a provider can talk with the person about the risks and benefits of the tests.8

Blood and urine tests in early pregnancy

  • MedlinePlus says a prenatal panel is a group of blood tests done in early pregnancy.9
  • MedlinePlus says the panel checks for diseases and infections that can affect the health of the pregnant person and the baby.9
  • MedlinePlus says the panel usually includes a complete blood count and a test for blood type and Rh factor.10
  • MedlinePlus says the panel also usually includes tests for rubella immunity, hepatitis, sexually transmitted infections and HIV.10
  • MedlinePlus says hepatitis B testing is usually given in pregnancy, but hepatitis C is not routinely tested because it is not common.11
  • MedlinePlus says testing for chlamydia and syphilis is usually done early in pregnancy.12
  • MedlinePlus says the panel tests are done in the first trimester, often at the first prenatal visit.13
  • MedlinePlus says treatment might be given to prevent serious health conditions if a panel result is not normal.14
  • MedlinePlus says Rh factor is a type of protein found on the surface of red blood cells.15
  • MedlinePlus says people whose blood cells have this protein are Rh-positive, and people whose cells do not are Rh-negative.16
  • MedlinePlus says Rh incompatibility is when a mother is Rh-negative and her developing baby is Rh-positive.17
  • MedlinePlus says Rh incompatibility may cause the mother's body to make antibodies that can damage the baby's red blood cells.17
  • MedlinePlus says a red blood cell antibody screen is usually done in early pregnancy.18
  • MedlinePlus says the screen looks for antibodies that could attack the fetus's red blood cells.19
  • MedlinePlus says that in anemia the blood does not carry enough oxygen to the rest of the body.20
  • MedlinePlus says such antibodies could cause a very serious type of fetal anemia.19
  • MedlinePlus says preeclampsia is a sudden increase in blood pressure after the 20th week of pregnancy.21
  • NICHD says a urine sample is tested at each prenatal visit for signs of diabetes, urinary tract infections and preeclampsia.22
  • In 2018 the US Preventive Services Task Force again recommended early syphilis screening for all pregnant women.23
  • The Task Force's statement says untreated syphilis in a pregnant woman can pass to the fetus at any time during pregnancy or at birth, which is called congenital syphilis.24
  • The Task Force said effective antibiotic treatment can prevent congenital syphilis, with small associated harms.23
  • In 2019 the Task Force again recommended hepatitis B screening for pregnant women at their first prenatal visit.25
  • In 2019 the Task Force recommended screening pregnant persons for bacteria in the urine without symptoms, using a urine culture.26
  • It concluded with moderate certainty that screening and treatment have a moderate net benefit in reducing perinatal complications.26

Screening for chromosome conditions

  • MedlinePlus says first trimester screening for Down syndrome (weeks 10 to 13) combines a blood test and an ultrasound.27
  • MedlinePlus says the blood test looks for markers, such as certain proteins, that may be linked to a higher risk of Down syndrome.27
  • MedlinePlus says the ultrasound measures the thickness of the fluid behind the fetus's neck.27
  • NICHD says nuchal translucency screening uses ultrasound to measure the thickness of the back of the fetus's neck between 11 and 14 weeks.28
  • NICHD says providers combine this with the mother's age and the results of a blood screen.29
  • NICHD says the combined information helps judge the fetus's potential risk for chromosomal abnormalities and other problems.29
  • MedlinePlus says second trimester screening, often called the quad screen, is done in weeks 15 to 20.30
  • MedlinePlus says the quad screen checks the levels of four substances in the blood.30
  • MedlinePlus says unusual levels of any of the four can suggest a higher chance of Down syndrome.30
  • NICHD says a blood screen done between 15 and 20 weeks assesses the risk of chromosomal abnormalities and neural tube defects.31
  • MedlinePlus describes neural tube defects as severe birth defects of the baby's brain and spine, such as spina bifida and anencephaly.32
  • MedlinePlus says cell-free DNA (cfDNA) screening is a blood test given during pregnancy.33
  • MedlinePlus says it checks DNA from the fetus that circulates in the mother's bloodstream.33
  • MedlinePlus says the screening checks whether the baby is more likely to have certain conditions caused by an abnormal number of chromosomes, such as Down syndrome.34
  • MedlinePlus says an extra copy of a chromosome is called a trisomy.35
  • MedlinePlus says cfDNA screening can be done as early as the 10th week of pregnancy.36
  • MedlinePlus says many providers recommend cfDNA screening for people at a higher risk of having a baby with a chromosome disorder.37
  • NICHD describes cfDNA screening for women at higher risk and says it is not recommended for women at low risk or women carrying multiple fetuses.38
  • NICHD's page cites a source from 2015 for this description of cfDNA screening.39
  • MedlinePlus says many providers also recommend cfDNA screening for people who are not at higher risk.40
  • MedlinePlus's Down syndrome tests page, updated in January 2026, says medical experts recommend cfDNA screening for everyone, regardless of age or risk level.41
  • These pages give different answers on who is offered cfDNA screening, and the newest, the MedlinePlus Down syndrome tests page, is the one that says everyone.38, 40, 41
  • MedlinePlus says cfDNA screenings are not as accurate in a pregnancy with more than one baby.42
  • MedlinePlus says a negative cfDNA result makes it unlikely that the baby has Down syndrome or another trisomy disorder.43
  • MedlinePlus says a positive cfDNA result means there is an increased risk that the baby has one of these disorders.44
  • MedlinePlus says a cfDNA screening cannot tell for sure whether a baby has a chromosome disorder.45
  • MedlinePlus says a provider will need to order other tests to confirm or rule out a diagnosis.45
  • MedlinePlus says a positive Down syndrome screening result means the baby's chance of having Down syndrome is higher than average.46
  • A high risk does not mean the baby will have Down syndrome, MedlinePlus says.46
  • MedlinePlus says a negative or normal screening result means the baby is unlikely to have Down syndrome.47
  • A screening test cannot guarantee that the baby will not have Down syndrome, MedlinePlus says.47

Diagnostic tests for chromosome conditions

  • MedlinePlus says diagnostic tests for Down syndrome usually follow a positive screening result, when a provider needs to confirm a diagnosis.48
  • MedlinePlus says amniocentesis is usually performed between 15 and 20 weeks of pregnancy.49
  • MedlinePlus says amniocentesis collects a small amount of the fluid around the fetus so that the fetal cells can be checked for chromosome changes.49
  • MedlinePlus says chorionic villus sampling (CVS) is usually done between 10 and 13 weeks of pregnancy.50
  • MedlinePlus says CVS collects tissue from parts of the placenta called the chorionic villi.50
  • MedlinePlus says amniocentesis and CVS are usually very safe procedures with a slight risk of causing a miscarriage.51
  • MedlinePlus says a person may choose diagnostic testing whether or not screening results were normal.52
  • MedlinePlus says diagnostic tests can usually tell whether or not a baby will have Down syndrome.53
  • MedlinePlus says diagnostic tests cannot predict how much Down syndrome will affect the baby's health and abilities.53

The routine ultrasound

  • MedlinePlus says a routine ultrasound between weeks 18 and 22 of pregnancy is common, to check on the health of the fetus.54
  • NICHD says an ultrasound exam is likely between 18 and 20 weeks to check for problems with the developing fetus.55
  • MedlinePlus says a pregnancy ultrasound may check the size, position, heart rate and age of the fetus.56
  • MedlinePlus says it may also show whether there is more than one fetus and whether the fetus is growing as expected.56, 57
  • MedlinePlus says it may also check the amount of amniotic fluid and where the placenta is.57
  • MedlinePlus says it may also screen for genetic disorders, such as Down syndrome, and for birth defects.58
  • MedlinePlus says normal pregnancy ultrasound results do not guarantee a healthy baby.59
  • Not all birth defects will show up on an ultrasound, MedlinePlus says.59
  • MedlinePlus says results that are not normal do not always mean the fetus has a serious health problem.60
  • A provider may suggest more tests to help confirm a diagnosis, MedlinePlus says.60
  • MedlinePlus says ultrasound has not been linked to any health harms.61
  • MedlinePlus says it is generally considered safe when trained sonographers use it correctly.61
  • MedlinePlus says ultrasound can affect fluids and tissues in the body in certain cases.62
  • MedlinePlus says most medical experts therefore recommend using ultrasound only when it is needed to provide important medical information.62

Gestational diabetes tests

  • NICHD says glucose challenge screening is usually given between 24 and 28 weeks of pregnancy.63
  • NICHD says this screening assesses the risk for gestational diabetes.63
  • MedlinePlus says a blood glucose test is likely between the 24th and 28th week of pregnancy to check for gestational diabetes.64
  • MedlinePlus says a person at high risk of gestational diabetes may be tested earlier.64
  • MedlinePlus says a glucose challenge test can screen for gestational diabetes and needs no fasting.65
  • MedlinePlus says a blood sample is taken one hour after a sugary drink.65
  • MedlinePlus says a high result usually leads to an oral glucose tolerance test to confirm or rule out gestational diabetes.66
  • MedlinePlus says an oral glucose tolerance test is used to diagnose gestational diabetes and needs fasting.67
  • NICHD says a glucose tolerance test may be ordered if the one-hour screening result is above a certain level.68
  • In 2021 the US Preventive Services Task Force recommended screening for gestational diabetes at 24 weeks of pregnancy or after in pregnant people without symptoms and without a prior diabetes diagnosis.69
  • It concluded with moderate certainty that this screening has a moderate net benefit to improve maternal and fetal outcomes.69
  • For screening before 24 weeks, the Task Force said the current evidence is insufficient to assess the balance of benefits and harms.70

Group B strep test

  • NICHD says group B streptococcus (GBS) screening is done between 35 and 37 weeks of pregnancy.71
  • NICHD says swabs take cells from the vagina and rectum for the test.71
  • MedlinePlus says group B strep testing is usually done between 36 and 38 weeks of pregnancy.72
  • MedlinePlus says a person who goes into labor before 36 weeks may be tested at that time.72
  • MedlinePlus says many healthy people have GBS bacteria, which are not harmful most of the time.73
  • MedlinePlus says a pregnant person can pass the bacteria to the baby during a vaginal delivery.74
  • MedlinePlus says serious illness in the baby from this is rare.74
  • NICHD says women who test positive for GBS will need antibiotics in labor.75
  • MedlinePlus says antibiotics during labor can protect the baby from infection.76

Tests added later in some pregnancies

  • NICHD lists the non-stress test as additional testing that a provider may recommend.77
  • NICHD says it is performed in the third trimester (28 weeks or later) to monitor the fetus's health.77
  • NICHD says a belt around the belly measures the fetal heart rate while the fetus is resting and while it moves.78
  • NICHD says the test can determine if the fetus is getting enough oxygen.78
  • NICHD says a biophysical profile, given in the third trimester, monitors the fetus's breathing, movement, muscle tone and heart rate.79
  • NICHD says the profile also checks the amount of amniotic fluid.79
  • NICHD says the biophysical profile includes an ultrasound test and a non-stress test.80

Topics the sources link to the choice of tests

  • Age, personal or family medical history, ethnic background and routine test results, which MedlinePlus says can lead a provider to offer other tests.7
  • A high risk of gestational diabetes, which MedlinePlus says may lead a provider to test earlier.64
  • Being pregnant with more than one baby, which MedlinePlus says makes cfDNA screening less accurate.42
  • A positive screening result, which MedlinePlus links to diagnostic testing.48

Questions to ask

  1. Which of these tests are offered in my pregnancy, and in which weeks?
  2. If a screening result is not normal, what are the next steps?
  3. What does each chromosome screening look for, and what does it leave unanswered?
  4. Are amniocentesis or CVS options for me, and what are the risks?
  5. Which tests did my first trimester blood panel include?
  6. When is my routine ultrasound, and what will it look at?
  7. When will I be tested for gestational diabetes, and what follows a high result?
  8. When will group B strep be checked, and what follows a positive result?
  9. Are any later tests, such as a non-stress test, expected in my pregnancy?

Sources

  1. Prenatal Testing (MedlinePlus health topic) Webpage, National Library of Medicine (MedlinePlus), What is prenatal testing?, paragraph 1, sentences 1 and 2. Retrieved .
  2. Prenatal Testing (MedlinePlus health topic) Webpage, National Library of Medicine (MedlinePlus), What are the two types of prenatal tests?, bullet 1, sentences 1 and 2. Retrieved .
  3. Prenatal Testing (MedlinePlus health topic) Webpage, National Library of Medicine (MedlinePlus), What are the two types of prenatal tests?, bullet 1, sentences 3 and 4. Retrieved .
  4. Prenatal Testing (MedlinePlus health topic) Webpage, National Library of Medicine (MedlinePlus), What are the two types of prenatal tests?, bullet 1, sentence 6. Retrieved .
  5. Prenatal Testing (MedlinePlus health topic) Webpage, National Library of Medicine (MedlinePlus), What are the two types of prenatal tests?, bullet 2. Retrieved .
  6. Prenatal Testing (MedlinePlus health topic) Webpage, National Library of Medicine (MedlinePlus), What is prenatal testing used to diagnose?, paragraph 2, sentence 2. Retrieved .
  7. Prenatal Testing (MedlinePlus health topic) Webpage, National Library of Medicine (MedlinePlus), What is prenatal testing used to diagnose?, paragraph 3 and bullets 1 to 4. Retrieved .
  8. Prenatal Testing (MedlinePlus health topic) Webpage, National Library of Medicine (MedlinePlus), What are the two types of prenatal tests?, paragraph 2, sentence 1 and part of sentence 2. Retrieved .
  9. Prenatal Panel (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What is a prenatal panel?, paragraph 1, sentences 1 and 2. Retrieved .
  10. Prenatal Panel (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What is a prenatal panel?, paragraph 1 (last sentence) and bullets 1 to 6. Retrieved .
  11. Prenatal Panel (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What is a prenatal panel?, bullet 4, sentences 3 and 4. Retrieved .
  12. Prenatal Panel (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What is a prenatal panel?, bullet 5, sentence 2. Retrieved .
  13. Prenatal Panel (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, Why do I need a prenatal panel?, paragraph 1, sentence 2. Retrieved .
  14. Prenatal Panel (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What do the results mean?, paragraph 1. Retrieved .
  15. Prenatal Panel (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What is a prenatal panel?, bullet 2, sentence 3. Retrieved .
  16. Prenatal Panel (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What is a prenatal panel?, bullet 2, sentences 4 and 5. Retrieved .
  17. Prenatal Panel (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What is a prenatal panel?, bullet 2, sentences 6 and 7. Retrieved .
  18. Red Blood Cell Antibody Screen (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, Why do I need an RBC antibody screen?, bullet 2, sentence 2. Retrieved .
  19. Red Blood Cell Antibody Screen (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What is it used for?, bullet 2. Retrieved .
  20. Anemia (MedlinePlus health topic) Webpage, MedlinePlus, National Library of Medicine, Summary, paragraph 1, sentence 1. Retrieved .
  21. High blood pressure in pregnancy (MedlinePlus health topic) Webpage, National Library of Medicine (MedlinePlus), What are the types of high blood pressure in pregnancy?, preeclampsia item, sentence 1. Retrieved .
  22. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Routine Tests, urine test. Retrieved .

  23. The USPSTF recommends early screening for syphilis infection in all pregnant women. It grades this an A recommendation. In 2018 it reaffirmed its earlier conclusion that there is convincing evidence that screening for syphilis infection in pregnant women provides substantial benefit, because effective antibiotic treatment can prevent congenital syphilis and significantly decrease adverse pregnancy outcomes, with small associated harms.

    Applies to Maternal
    • All pregnant women.
    • Not stated in the PubMed abstract
    • United States (statement of the US Preventive Services Task Force); the abstract names no country.
    • Pregnancy, early
    • Gestational age Not reported
    • Postnatal age Not reported
    Follow-up Not applicable (recommendation context)

    Limitations. This was a reaffirmation based on an evidence update, not a new full review. Only the PubMed abstract was read. The abstract does not name the screening tests.

  24. Screening for Syphilis Infection in Pregnant Women: US Preventive Services Task Force Reaffirmation Recommendation Statement Publication, JAMA, Abstract, IMPORTANCE, sentence 1. Retrieved .

  25. The USPSTF recommends screening for hepatitis B virus (HBV) infection in pregnant women at their first prenatal visit. It grades this an A recommendation. In 2019 it reaffirmed its previous conclusion that there is convincing evidence that screening for HBV infection in pregnant women provides substantial benefit. The abstract says interventions are effective for preventing perinatal transmission.

    Applies to Maternal
    • Pregnant women, screened at their first prenatal visit.
    • Not stated in the PubMed abstract
    • United States (statement of the US Preventive Services Task Force); the abstract names no country.
    • Pregnancy, first prenatal visit
    • Gestational age Not reported
    • Postnatal age Not reported
    Follow-up Not applicable (recommendation context)

    Limitations. This was a reaffirmation based on an evidence update. PubMed links a published erratum (PMID 31528989, titled Incorrect Language in Figure and Text); its PubMed and PMC records hold only the title and no correction text (the correction is in the journal PDF, which was not fetched), so whether it changes anything in this claim is not known. Only the PubMed abstract of the statement was read.

  26. The USPSTF recommends screening pregnant persons for asymptomatic bacteriuria using urine culture. It grades this a B recommendation and concludes with moderate certainty that screening for and treatment of asymptomatic bacteriuria in pregnant persons has a moderate net benefit in reducing perinatal complications.

    Applies to Maternal
    • Pregnant persons of any age without signs and symptoms of a urinary tract infection.
    • Not stated in the PubMed abstract
    • United States (statement of the US Preventive Services Task Force); the abstract names no country.
    • Pregnancy
    • Gestational age Not reported
    • Postnatal age Not reported
    Follow-up Not applicable (recommendation context)

    Limitations. The same USPSTF statement recommends against screening for asymptomatic bacteriuria in nonpregnant adults (a D recommendation); that is outside this claim. The abstract finds the harms of treatment (adverse effects of antibiotics and changes to the microbiome) to be at least small in magnitude. The PubMed abstract prints each grade after its statement, so the B appears at the start of the next sentence. USPSTF certainty levels are the task force’s own wording and not a GRADE rating.

  27. Down Syndrome Tests (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What are the tests used for?, first trimester screening item and its two sub-items. Retrieved .
  28. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Screening for Chromosomal and Neural Tube Defects (NTDs) and Other Conditions, nuchal translucency screening, sentence 2. Retrieved .
  29. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Screening for Chromosomal and Neural Tube Defects (NTDs) and Other Conditions, nuchal translucency screening, sentence 3. Retrieved .
  30. Down Syndrome Tests (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What are the tests used for?, second trimester screening item. Retrieved .
  31. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Screening for Chromosomal and Neural Tube Defects (NTDs) and Other Conditions, maternal serum screen, sentences 2 and 3. Retrieved .
  32. Amniocentesis (amniotic fluid test) (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What is it used for?, bullet 5 under genetic and chromosomal disorders. Retrieved .
  33. Prenatal Cell-Free DNA Screening (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What is a prenatal cell-free DNA (cfDNA) screening?, paragraph 1, sentences 1 and 2. Retrieved .
  34. Prenatal Cell-Free DNA Screening (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What is a prenatal cell-free DNA (cfDNA) screening?, paragraph 1, sentence 3. Retrieved .
  35. Prenatal Cell-Free DNA Screening (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What is a prenatal cell-free DNA (cfDNA) screening?, bullet 2, sentence 1. Retrieved .
  36. Prenatal Cell-Free DNA Screening (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What is used for?, paragraph 3. Retrieved .
  37. Prenatal Cell-Free DNA Screening (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), Why do I need a prenatal cfDNA screening?, paragraph 1, sentence 1. Retrieved .
  38. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Screening for Chromosomal and Neural Tube Defects (NTDs) and Other Conditions, cell-free fetal DNA, sentences 3 and 4. Retrieved .
  39. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Citations, note 3 (the note that follows the cell-free fetal DNA item). Retrieved .
  40. Prenatal Cell-Free DNA Screening (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), Why do I need a prenatal cfDNA screening?, paragraph 2, sentences 1 and 2. Retrieved .
  41. Down Syndrome Tests (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What are the tests used for?, cell-free DNA item, sentence 4. Retrieved .
  42. Prenatal Cell-Free DNA Screening (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), Is there anything else I need to know about a prenatal cfDNA screening?, paragraph 1. Retrieved .
  43. Prenatal Cell-Free DNA Screening (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What do the results mean?, paragraph 1. Retrieved .
  44. Prenatal Cell-Free DNA Screening (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What do the results mean?, paragraph 2, sentences 1 and 2. Retrieved .
  45. Prenatal Cell-Free DNA Screening (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What is a prenatal cell-free DNA (cfDNA) screening?, paragraph 3, sentences 2 and 3. Retrieved .
  46. Down Syndrome Tests (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What do the results mean?, bullet 1, sentences 1 and 3. Retrieved .
  47. Down Syndrome Tests (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What do the results mean?, bullet 2. Retrieved .
  48. Down Syndrome Tests (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What are the tests used for?, paragraph 3, sentence 2. Retrieved .
  49. Down Syndrome Tests (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What are the tests used for?, amniocentesis item. Retrieved .
  50. Down Syndrome Tests (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What are the tests used for?, chorionic villus sampling item. Retrieved .
  51. Prenatal Cell-Free DNA Screening (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What do the results mean?, paragraph 3. Retrieved .
  52. Down Syndrome Tests (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What do the results mean?, paragraph 2, sentence 1. Retrieved .
  53. Down Syndrome Tests (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What do the results mean?, paragraph 2, sentences 2 and 3. Retrieved .
  54. Ultrasound (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), Why do I need an ultrasound?, paragraph 1. Retrieved .
  55. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Routine Tests, ultrasound exam. Retrieved .
  56. Ultrasound (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What is it used for?, paragraph 2 and bullets 1 and 2. Retrieved .
  57. Ultrasound (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What is it used for?, bullets 4 and 5. Retrieved .
  58. Ultrasound (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What is it used for?, pregnancy ultrasound list, bullet 3. Retrieved .
  59. Ultrasound (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What do the results mean?, paragraph 1 and bullet 3. Retrieved .
  60. Ultrasound (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), What do the results mean?, paragraph 3. Retrieved .
  61. Ultrasound (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), Are there any risks to the test?, paragraph 1, sentences 1 and 2. Retrieved .
  62. Ultrasound (MedlinePlus medical test) Webpage, National Library of Medicine (MedlinePlus), Are there any risks to the test?, paragraph 2. Retrieved .
  63. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Routine Tests, glucose challenge screening, sentences 1 and 2. Retrieved .
  64. Blood Glucose Test (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, Why do I need a blood glucose test?, pregnancy item, sentences 2 and 3. Retrieved .
  65. Blood Glucose Test (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What happens during a blood glucose test?, glucose challenge test item, sentences 1 to 4. Retrieved .
  66. Blood Glucose Test (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What happens during a blood glucose test?, glucose challenge test item, sentence 5. Retrieved .
  67. Blood Glucose Test (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What happens during a blood glucose test?, oral glucose tolerance test item, sentences 1 and 3. Retrieved .
  68. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Additional Testing that Your Health Care Provider May Recommend, glucose tolerance test, sentence 2 and the last sentence. Retrieved .

  69. The USPSTF recommends screening for gestational diabetes in asymptomatic pregnant persons at 24 weeks of gestation or after. It grades this a B recommendation and concludes with moderate certainty that there is a moderate net benefit to screening for gestational diabetes at 24 weeks of gestation or after to improve maternal and fetal outcomes.

    Applies to Maternal
    • Asymptomatic pregnant persons who have not been previously diagnosed with type 1 or type 2 diabetes, at 24 weeks of gestation or after.
    • Not stated in the PubMed abstract
    • United States (statement of the US Preventive Services Task Force); the abstract names no country.
    • Pregnancy, 24 weeks of gestation or after
    • Gestational age at least 24 weeks 0 days, measured at the time of measurement
    • Postnatal age Not reported
    Follow-up Not applicable (recommendation context)

    Limitations. The recommendation is for screening in general. It does not choose between the one-step and two-step tests, which is why it is linked to the page on glucose tests. PubMed links a published erratum (PMID 34609473, titled Incorrect Value in Table); its PubMed and PMC records hold only the title and no correction text (the correction is in the journal PDF, which was not fetched), so whether it changes anything in this claim is not known. The PubMed abstract prints each grade after its statement, so the B appears at the start of the next sentence. USPSTF certainty levels are the task force’s own wording and not a GRADE rating. Only the PubMed abstract was read.

  70. The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for gestational diabetes in asymptomatic pregnant persons before 24 weeks of gestation. It labels this an I statement and says the balance of benefits and harms of screening cannot be determined.

    Applies to Maternal
    • Asymptomatic pregnant persons who have not been previously diagnosed with type 1 or type 2 diabetes, before 24 weeks of gestation.
    • Not stated in the PubMed abstract
    • United States (statement of the US Preventive Services Task Force); the abstract names no country.
    • Pregnancy, before 24 weeks of gestation
    • Gestational age up to 23 weeks 6 days, measured at the time of measurement
    • Postnatal age Not reported
    Follow-up Not applicable (recommendation context)

    Limitations. An I statement is a statement about the evidence, not a recommendation against early testing. The PubMed abstract prints each grade after its statement, so the I appears at the start of the next sentence. PubMed links a published erratum (PMID 34609473, Incorrect Value in Table); its correction text was not read, so whether it changes this claim is not known.

  71. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Routine Tests, group B streptococcus infection screening, sentences 2 and 3. Retrieved .
  72. Group B Strep Test (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, Why do I need a group B strep test?, paragraph 1, sentences 3 and 4. Retrieved .
  73. Group B Strep Test (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What is a group B strep test?, paragraph 1, sentence 2, and paragraph 2, sentence 1. Retrieved .
  74. Group B Strep Test (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What is a group B strep test?, paragraph 3, sentence 2 and its last sentence. Retrieved .
  75. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Routine Tests, group B streptococcus infection screening, sentence 4. Retrieved .
  76. Group B Strep Test (MedlinePlus medical test information) Webpage, MedlinePlus, National Library of Medicine, What is a group B strep test?, paragraph 9, sentence 2. Retrieved .
  77. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Additional Testing that Your Health Care Provider May Recommend, non-stress test, sentences 1 and 2. Retrieved .
  78. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Additional Testing that Your Health Care Provider May Recommend, non-stress test, sentences 3 and 4. Retrieved .
  79. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Additional Testing that Your Health Care Provider May Recommend, biophysical profile, sentence 2. Retrieved .
  80. What tests might I need during pregnancy? | NICHD Webpage, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Additional Testing that Your Health Care Provider May Recommend, biophysical profile, sentence 3. Retrieved .

About this guide

Written for
Pregnant people, and the people with them
What it covers
Written from MedlinePlus and NICHD pages, both US government sources, and from US Preventive Services Task Force statements. The weeks are the ones each page gives, and pages differ.
Pages it explains
Sources checked
2026-10-15
Next check due
2027-04-15
Reading level
Estimated grade 9.8 (target 10)

Every sentence cites a source. Words in quotation marks are the source's own; the rest is the atlas's summary.

https://maternal.openmedicalatlas.org/guides/tests-in-pregnancy/ · Release cb1244a2c7003676, built 2026-10-15