Screening Women During Labor and Delivery
Since the first case of pediatric HIV infection was documented in 1984, there have been tremendous medical and public health achievements in preventing mother-to-child transmission of HIV. When the recommended antiretroviral and obstetric interventions are used, a woman who knows of her HIV infection early in pregnancy now has a less than 1% chance of delivering an HIV-infected infant. Without intervention, this risk is approximately 25% in the United States. CDC’s revised Recommendations for HIV Testing of Adults, Adolescents, and Pregnant Women in Health-Care Settings, released in 2006, further recommend that.
- HIV screening should be included in the routine panel of prenatal screening tests for all pregnant women;
- HIV screening should be offered after the patient is notified that testing will be performed unless the patient declines (opt-out screening);
- Separate written consent for HIV testing should not be required; general consent for medical care should be considered sufficient to encompass consent for HIV testing;
- Repeat screening in the third trimester should be conducted in certain jurisdictions with elevated rates of HIV infection among pregnant women.
Before effective therapy, nearly 26% of infants of HIV-infected women were born with HIV infection. Through the use of HIV screening and appropriate medical care, the number of infants born with HIV infection decreased from a high of 1,650 HIV-infected infants born in 1991 to an estimated 144–236 infants born in 2002.
However, in 2000, of the approximately 6,000 to 7,000 HIV-infected women who gave birth in the United States, an estimated 40 percent had not been diagnosed with HIV before labor and delivery (Office of the Inspector General, Department of Health and Human Services, 2002).
If a pregnant woman is infected with HIV, there is still an opportunity to prevent transmission to her infant, by the administration of antiretroviral medications and appropriate medical care if HIV is diagnosed at the time of labor.
Ideally, all women should be screened for HIV during each pregnancy at their initial prenatal care visit or as early in pregnancy as possible. CDC also recommends a second HIV test during a woman’s third trimester for women who meet certain criteria, including: a) those who continue behaviors with a high risk for acquiring HIV, b) residing in specific high-prevalence jurisdictions, and c) receiving health care in facilities with at least 1 diagnosed HIV case per 1,000 pregnant women per year.
Preventive antiviral therapy is most effective when it is initiated early in pregnancy. However, starting antiretroviral treatment during labor and delivery, or even providing it to the newborn within hours after birth can reduce mother-to-child transmission by half (Wade et al. 1998; Kourtis et al. 2001; Guay et al. 1999). To maximize the benefit, it is important to obtain HIV test results for women in labor quickly in order to start antiretroviral therapy as soon as possible.
CDC recommends that clinicians test for HIV any newborn whose mother’s HIV status is unknown. For those women whose HIV status is unknown at labor, CDC recommends routine, rapid HIV testing. When the mother’s HIV status is unknown prior to the onset of labor and rapid HIV testing is not done during labor, CDC recommends rapid HIV testing of the infant immediately post-partum, so that antiretroviral prophylaxis can be offered to HIV-exposed infants. When intervention begins at the intrapartum (during labor or delivery) or neonatal periods, 9% to 13% HIV transmission rates are achievable based on clinical trial and observational data. This represents a 50% reduction in HIV transmission from rates that would be expected without intervention.
Rapid HIV tests that can be performed right in labor and delivery can yield results in less than 45 minutes. Such timely knowledge of the mother’s HIV status also provides opportunities for other interventions that reduce transmission, such as elective cesarean section, avoiding artificial rupture of membranes, and avoiding breastfeeding (Recommendations for the Use of Antiretroviral Drugs in Pregnant Women with HIV Infection and Interventions to Reduce Perinatal HIV Transmission in the United States external icon). CDC’s Mother-Infant Rapid Intervention at Delivery (MIRIAD) study proved rapid testing is feasible and effective.
Lack of Timely Test Results Can Be a Barrier to Implementation
The Office of the Inspector General (OIG) in the Department of Health and Human Services (DHHS) found that significant barriers prevented almost half of obstetricians from routinely offering HIV testing during labor and delivery (OIG/DHHS 2002). Nearly 20% of obstetricians cited the inability of available HIV testing technology to produce timely results, specifically “test results take too long” and “rapid or expedited HIV test results are not available.” The American College of Obstetricians and Gynecologists identified the lack of rapid or expedited HIV tests more frequently than any other barrier to testing during labor or delivery.
Based on its findings, OIG recommended that CDC help States develop and implement protocols for HIV testing during labor and delivery in order to promote testing in this setting as the standard of care. In response, CDC developed the Practical Guide and Model Protocolexternal icon.
- Centers for Disease Control and Prevention. Revised Recommendations for HIV Testing of Adults, Adolescents, and Pregnant Women in Health-Care Settings. MMWR 2006; 55 (RR-14).
- Guay LA, Musoke P, Fleming T, et al. Intrapartum and neonatal single-dose nevirapine compared with zidovudine for prevention of mother-to-child transmission of HIV-1 in Kampala, Uganda: HIVNET 012 randomised trial. Lancet 1999; 354:795-802. [Abstractexternal icon]
- Institute of Medicine, National Research Council. Reducing the Odds: Preventing Perinatal Transmission of HIV in the United States. Washington, DC: National Academy Press, 1999.
- Kourtis AP, Bulterys M, Nesheim SR, Lee FK. Understanding the Timing of HIV Transmission from Mother to Infant. JAMA 2001;285:(6): 709-12
- Office of Inspector General, Health and Human Services. Reducing Obstetrician Barriers to Offering HIV Testingpdf iconexternal icon. OEI-05-01-00260. Washington, DC: Department of Health and Human Services, April 2002.
- Wade NA, Birkhead GS, Warren BL, et al. Abbreviated regimens of zidovudine prophylaxis and perinatal transmission of the human immunodeficiency virus. New England Journal of Medicine 1998; 339:1409-14. [Abstractexternal icon]
The MIRIAD study aims to learn more about the dynamics of mother-to-child HIV transmission and how to use the available interventions to their best advantage after offering rapid HIV testing to women who do not know their HIV status late in pregnancy or at the time of delivery. The study will include more than 14 hospitals in six cities: Atlanta, Baton Rouge, Chicago, Miami, New Orleans, and New York City. CDC secured a Treatment Investigational Device Exemption from the Food and Drug Administration (FDA) to use the OraQuick rapid HIV-1 antibody test for women in the MIRIAD study before the test was FDA-approved because it is suitable for point-of-care use with whole blood and offers rapid turnaround for test results. Women in the study are offered antiretroviral therapy on the basis of the OraQuick test result. OraQuick results are also compared to enzyme immunoassay (EIA) and, if positive, to Western blot results as soon as these become available. The table below summarizes MIRIAD’s experience with the OraQuick rapid test since the study began in November 2001.
|OraQuick Testing in the MIRIAD Study
11/15/01 – 02/13/05
|8165 pregnant women tested|
|54 HIV-positive mothers identified|
|No false-negative (OraQuick or EIA) tests|
|6 false-positive OraQuick tests|
|18 false-positive EIA tests|
Rapid HIV Testing of Women in Labor and Delivery: A Practical Guide and Model Protocol
For women with unknown HIV status at labor and delivery, the model protocol offers guidance to clinicians, laboratorians, hospital administrators, and policy makers. In conjunction with the model protocol, CDC formulated practical tips for overcoming barriers to implementing rapid testing in the labor and delivery setting. The U.S. Public Health Service Perinatal HIV Guidelines Working Group publishes Recommendations for the Use of Antiretroviral Drugs in Pregnant Women with HIV Infection and Interventions to Reduce Perinatal HIV Transmission in the United Statesexternal icon.