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Screening for Infection in Pregnancy

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The purpose of screening is early diagnosis and treatment of an infection. Screening tests are usually given to people without current symptoms, but who may be at high risk for certain diseases or conditions.

You will get several screening tests as part of your routine prenatal care. Screening tests can help your doctor know if you are at risk for certain infections during pregnancy. Tests may include:

  • Blood test—Your blood is checked for the presence of antibodies. Antibodies are proteins that your body has made to fight an infection.
  • Culture—The doctor will gently swab your anus, rectum, and/or vagina, and cervix to see if an infection is present. The culture will either be looked at under a microscope in the office or sent to a lab for testing.
  • Ultrasound—A technician will hold a device over the abdomen that bounces sound waves off the uterus and your developing baby. The sound waves make electrical impulses that create a picture of the baby on a video monitor. This helps the doctor check for any fetal abnormalities that might indicate an infection (usually viral) in the mother.
  • Urinalysis—This is a test to check for bacteria in the urine. After you urinate into a cup, your healthcare provider will use a specially treated paper strip to check for signs of a bacterial infection in the urine.

The Centers for Disease Control and Prevention (CDC) recommends that pregnant women are screened for sexually transmitted diseases (STDs) on their first prenatal visit. Screening will look for the following STDs:

In some cases, your doctor will also screen you for Hepatitis C and bacterial vaginosis.

The CDC also recommends that you are screened for Group B streptococcal disease (GBS) at 35-37 weeks. If the test is positive, you will be given antibiotics to treat this infection during labor.

A pre-pregnancy checkup can help you avoid infection in pregnancy and improve the chances of having a healthy baby. At a pre-pregnancy visit, your healthcare provider will ask about your medical history, past pregnancies, and lifestyle. You can ask questions and discuss concerns, such as whether work or hobbies expose you to potential hazards.

Blood tests measure immunity to certain infections. If you have immunity, you cannot get the infection again. If you do not have immunity, you may be able to get a vaccine to protect you from the infection. During a pre-pregnancy visit, you can be checked for:

  • Varicella—Women not immune can be vaccinated before pregnancy. Conception should be postponed for three months.
  • Hepatitis B—The Centers for Disease Control and Prevention (CDC) recommends that all pregnant women be screened for hepatitis B. Untreated infants of infected mothers have about a 50% risk of getting the virus. Prompt immunization and treatment after birth usually can prevent infection in the baby. However, high-risk women, such as healthcare workers, should consider vaccination prior to pregnancy.
  • Rubella—If you are not immune, you can be vaccinated before pregnancy. Conception should be postponed for three months after the vaccination.
  • Toxoplasmosis—Some healthcare providers screen for immunity to this infection. Unless a woman knows she is immune, she should not eat undercooked or raw meat, or handle cat litter.
  • Cytomegalovirus (CMV)—Healthcare and childcare workers may want to be tested for CMV before pregnancy to see if they have had CMV in the past. Routine screening for low-risk women is not recommended. If you already have had CMV, you have little cause for concern during pregnancy.
  • Tuberculosis (TB)—If you are from a country that has high rates of TB, you should be screened for this disease.

Revision Information

  • Apgar BS, Greenberg G, et al. Prevention of group B streptococcal disease in the newborn. Am Fam Physician. 2005;71:903-910. Available at http://www.aafp.org/afp/2005/0301/p903.html.

  • ACOG practice bulletin. Perinatal viral and parasitic infections. Number 20, September 2000. Int J Gynaecol Obstet. 2002 76(1):95-107. Reaffirmed 2011.

  • Bacterial vaginosis - CDC fact sheet. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/std/BV/STDFact-Bacterial-Vaginosis.htm. Updated September 1, 2010. Accessed July 29, 2013.

  • Chorioamnionitis. Cleveland Clinic website. Available at: http://www.clevelandclinic.org/health/health-info/docs/3800/3857.asp?index=12309 . Accessed July 29, 2013.

  • Cytomegalovirus (CMV) and congenital CMV infection. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/cmv/index.html. Updated July 28, 2010. Accessed July 29, 2013.

  • Group B Strep (GBS). Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/groupbstrep/index.html. Updated May 23, 2012. Accessed July 29, 2013.

  • Listeria and pregnancy. American Pregnancy Association website. Available at: http://www.americanpregnancy.org/pregnancyhealth/listeria.html. Updated June 2011. Accessed July 29, 2013.

  • Pregnancy and fifth disease. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/parvovirusB19/pregnancy.html. Updated February 14, 2012. Accessed July 29, 2013.

  • Schrag SJ, Arnold KE, et al. Prenatal screening for infectious diseases and opportunities for prevention. Obstet Gynecol . 2003;102:753-760.

  • STDs and pregnancy. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/std/pregnancy/STDFact-Pregnancy.htm. Updated July 10, 2013. Accessed July 29, 2013.

  • Toxoplasmosis. American Academy of Family Physicians Family Doctor website. Available at: http://familydoctor.org/familydoctor/en/diseases-conditions/toxoplasmosis.html. Updated January 2011. Accessed July 29, 2013.

  • Urinary tract infection during pregnancy. American Pregnancy Association website. Available at: http://www.americanpregnancy.org/pregnancycomplications/utiduringpreg.html. Updated April 2006. Accessed July 29, 2013.

  • Varicella. EBSCO DynaMed website. Available at: https://dynamed.ebscohost.com/about/about-us. Updated April 13, 2013. Accessed July 29, 2013.