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Prenatal screens and tests

  • Parents worry about their baby's growth and development. It is a sign of wanting to be a good parent.

    Regular prenatal visits will help ensure the best possible health for your baby. At each visit your weight, blood pressure, and the size of your uterus will be monitored. These measurements can be reassurance that your pregnancy is going well.

    Regular visits can also alert your health care provider to early signs of a problem. Early detection usually means problems can be treated more easily.

    At some visits you will be offered screening for specific concerns. These are optional tests.

    There are other tests to identify potential problems related to you or your baby's health. Your health care provider will review the tests that are available to you.

    Prenatal screening


    Your health care provider will determine if your urine will be checked for protein and sugar based on conditions in your pregnancy.

    Knowing about some problems before your baby is born can help you and your health care provider be better prepared.

    No test can guarantee that you will have a healthy baby. There are no tests that can identify all types of birth defects and developmental problems. However, prenatal screens may help predict if you have an increased risk of carrying a baby with some specific problems.

    Screens are options for all pregnant women to assess their risk of having a baby with a specific birth defect or genetic disorder. This can be helpful because most birth defects occur without the parents having an obvious risk factor.

    It may be better to have a diagnostic test rather than a screen if you already have a known increased risk or concern. Genetic counseling can help you understand your options.

    When the screening result is "positive," you are in a higher-risk category. It does not mean your baby has the problem. If you are at an increased risk, you have the option for diagnostic testing and/or genetic counseling to understand the risks and clarify concerns.

    A diagnostic test can determine if there actually is a problem. A "normal" or "negative" screen result indicates you are in a low-risk category. It does not definitely rule out the problem.

    Screens or tests: Why they may be offered

    Chorionic villus sampling (CVS)

    A small amount of tissue is removed from your baby's developing placenta. These cells should have the same genetic and biochemical makeup as your baby. The cells are grown in a culture, and the chromosomes are studied.

    If the family history indicates additional concerns, other DNA or biochemical tests may also be done. The sampling procedure is done using ultrasound to guide a catheter through your vagina and cervix. The sample can also be taken using ultrasound to guide a needle through your abdomen.

    Chorionic villus sampling (CVS) is usually used to determine if your baby has specific genetic problems. The concern may be related to your age, family history, use of assisted reproductive techniques, the results of a screen, or other factors. The test is usually done at 10 to 12 weeks. American College of Obstetricians and Gynecologists supports this option for all pregnant women.


    Secretions and cells from the vagina and/or cervix are collected and analyzed.

    Helps identify sexually transmitted diseases so they can be treated and your baby will not be at risk.

    Cystic fibrosis carrier test

    This is a blood or saliva test that can identify most carriers of an altered gene for cystic fibrosis (CF).

    If you test positive, your partner will also be offered testing. Babies must have two altered CF genes in order to get cystic fibrosis.

    To determine if your baby is at risk for cystic fibrosis. If both of you are carriers, your baby has a one in four chance of getting CF.

    Because most parents do not learn they are carriers until they have an affected child, the test is offered to all couples.

    First trimester combined screen

    An ultrasound is used to measure the fluid area behind the baby’s neck (nuchal translucency). This is combined with a blood test to measure two proteins made by the baby and placenta (PAPP-A and HCG).

    This combined screen can help identify most women who may carry a baby with Down syndrome and some other chromosomal problems. Those who are high risk are offered CVS or amniocentesis to determine if there is a problem or rule it out. ACOG supports this option for all pregnant women.

    For an even better detection rate, this combined screen can be done as part of a step-by-step process that includes a multiple marker screen in the second trimester. This is called sequential of integrated screening. Ask your health care provider or genetic counselor about this option.

    An increased nuchal translucency may also suggest a higher risk for some heart defects. Your baby’s heart can be checked using a detailed ultrasound later in pregnancy.

    HIV test

    This blood test detects whether or not you have been exposed to HIV, the virus that causes AIDS.

    HIV testing is recommended for all women. Early detection and treatment can reduce a baby's chances of getting HIV to 5 percent or less. You cannot be denied insurance on the basis of a positive HIV test.

    Pap test

    A swab collects cervical cells that are then viewed under a microscope.

    This test, also called Pap smear, is part of women's health care to detect changes in cervical cells that indicate infection or abnormal cells that can become cancerous.

    Prenatal profile

    Blood is drawn from your arm and analyzed.

    This profile is part of standard care to determine blood type and RH factor. It also determines whether you are anemic, have immunity to German measles ( rubella), and have been infected with hepatitis B or syphilis.


    A transducer that sends sound waves is placed on your abdomen or in your vagina. It creates a picture of your baby on a monitor screen.

    Ultrasound is used to determine your baby's age, your due date, and to detect more than one baby. It can also be used to detect a variety of physical birth defects, measure your baby's growth, and assess well-being.

    You may or may not be able to tell your baby's gender from an ultrasound.

    Questions to ask

    Ask your health care provider these questions when considering the tests listed on this page:

    • What do you hope to learn from this test?
    • How accurate is it?
    • How many times have you (or the doctor/technician) done this procedure before?
    • What risks does this test pose to my baby and me?
    • Who "reads" the test results? How reliable are the results?
    • When the results come back, what options will I have?
    • What are the alternatives to having this test?
    • Where can I learn more about this test?

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This site is presented for information only and is not intended to substitute for professional medical advice. Allina Health®, Allina®, the Allina Health logo, and Medformation® are registered trademarks of Allina Health System. Presentation and Design ©2015 Allina Health. ALL RIGHTS RESERVED