An estimated 120,000 to 160,000 women in the United States are living with the virus, and many do not know it (1). About 80 percent of these women are of childbearing age (1). Since 1985, approximately 9,400 children in the United States have contracted AIDS, and about 5,000 have died (1, 2). More than 90 percent contracted the virus from their mothers during pregnancy or birth (2).

A 1994 government study showed that drug treatment during pregnancy greatly reduces the risk that an HIV-infected mother will pass the virus on to her baby (3). Since then, the number of babies in the United States who contract the virus from their mothers has dropped dramatically, from a high of about 1,650 in 1991 to an estimated 144 to 236 in 2004 (4). 

The Centers for Disease Control and Prevention (CDC) recommends that all pregnant women be screened for HIV infection (4). The CDC advises that providers inform pregnant women that HIV testing is routinely included in the standard blood tests for all pregnant women, unless a woman declines the HIV test or she lives in a state that mandates pretest counseling and written informed consent.

The CDC also recommends that the test be repeated in the third trimester for women who are at increased risk of HIV infection or who live in an area with high rates of HIV infection (4). Women who learn they carry the virus can get treatment to help protect their babies.

New treatments, along with the use of cesarean section in certain circumstances, can reduce the risk of a mother passing HIV on to her baby to 2 percent or less (4). However, more than 500,000 babies worldwide contract HIV from their mothers each year (5). About 90 percent of these cases occur in developing countries where new treatments are not widely available. Researchers are studying new approaches to preventing HIV infection in these areas. There are many initiatives to make medications available throughout the world.

What does it mean to have HIV/AIDS?
After HIV enters the bloodstream, the body begins to produce disease-fighting antibodies. If a blood test detects these antibodies, the person is considered “HIV-positive” but does not necessarily have AIDS. A person who is HIV-positive is infected with the virus and can transmit it to others. Even with no treatment, it can take 10 or more years for an HIV-positive person to develop AIDS.

A person with HIV or AIDS cannot fight off certain diseases as well as uninfected people and is more susceptible to infections, certain cancers and other problems that can be life-threatening or fatal. With new powerful drug regimens, the outlook for HIV-infected individuals has improved dramatically.

How are most women infected?
The most common way women become infected is through unprotected (without a condom) heterosexual intercourse with infected partners. The CDC (2) estimates that:

• About 75 percent of new infections in women in the United States are contracted through heterosexual intercourse
• About 20 percent by injection drug use (sharing of drug needles)

A small number of women have been infected by receipt of blood transfusion, blood components or tissue.

Between 1985 and 2004, the proportion of all AIDS cases reported among women in the United States more than tripled, from 7 percent to 27 percent (6). Women are more likely than men to become infected via heterosexual sex.

Women at highest risk of sexually acquired HIV infection include:

• Women whose heterosexual partners use IV drugs
• Women whose partners also have sex with men
• Adolescents and young adults with multiple sex partners
• Women with sexually transmitted infections other than HIV

Who should be tested for HIV?
The CDC recommends screening for all adults and adolescents between the ages of 13 and 64 as part of routine medical care (4). Ideally, all women should be aware of their HIV status before conception. The March of Dimes urges all women of childbearing age who suspect that they could have been exposed to HIV to be tested before they become pregnant. Women not tested before pregnancy should be screened during pregnancy.

Women who have not been tested during pregnancy can be tested during labor and delivery with tests that produce results quickly. This allows treatment, when necessary, to help protect the baby.

How should women with HIV/AIDS be treated during pregnancy?
People with HIV/AIDS are generally treated with combinations of HIV-fighting drugs. These drug combinations often slow the spread of HIV in the body, keep blood levels of the virus low (or even undetectable), and help prevent AIDS-related infections. The U.S. Public Health Service recommends that an HIV-infected pregnant woman should receive treatment with these drugs just as if she were not pregnant, though medications may be modified (7).

If a woman learns she has HIV in her first trimester and she has not yet been treated with any HIV-fighting drugs, she should be evaluated and treated. In some cases, she may be able to postpone treatment until her second trimester (when any drug-related risks to the fetus are lower).

An infected pregnant woman who is already taking HIV-fighting drugs should continue to take them throughout pregnancy. However, her doctor may recommend adjusting or changing medications.

It is not yet known whether HIV-fighting drugs may pose a risk to the fetus, but to date, the risk appears low with most of these drugs. However, a few of these drugs, including efavirenz (Sustiva) and hydroxyurea, generally are not recommended in pregnancy because they may pose a risk of birth defects (7). 

What treatment helps prevent HIV/AIDS in babies of HIV-infected mothers?
The U.S. Public Health Service recommends that HIV-infected pregnant women be offered combination treatment with HIV-fighting drugs to help protect their health and to help prevent passing the infection on to their babies (7). Infected pregnant women should take the drug zidovudine (ZDV) as part of their drug regimen, starting in the early second trimester, and continuing throughout pregnancy and labor and delivery. The baby also should be treated with ZDV for the first six weeks of life. Women who do not yet need combination treatment for their own health may choose to be treated with ZDV alone. However, studies suggest that newer HIV-fighting drugs (such as protease inhibitors) may reduce the risk to the baby more than ZDV alone because they greatly reduce the levels of the virus in the blood (7). 

The recommendation to include ZDV in the drug regimen is based on a 1994 study by the National Institutes of Health (NIH) (7). The study found that giving ZDV to an HIV-positive pregnant woman and to her baby at birth decreased by two-thirds her risk of passing the infection on to her baby (3). Eight percent of babies of women treated with ZDV became infected, compared with 25 percent of babies of untreated women. Neither mothers nor babies had significant side effects from the drug treatment, other than a mild anemia in some treated infants that cleared up when the drug was stopped. Studies show that the HIV-negative treated babies continue to develop normally through age 6 (7).   

Women who have not received any drug treatment before labor should be treated with one of several drug regimens during labor. These may include ZDV alone, nevirapine alone, a combination of ZDV and lamivudine (also called 3TC) or nevirapine and ZDV. Studies suggest that even these short durations of treatment may help reduce the risk of passing the infection on to the baby by about half (7). If the mother is treated with single-dose nevirapine, alone or in combination with ZDV, her doctor may recommend treatment with ZDV/3TC starting as soon as possible after delivery and continuing for three to seven days. This additional treatment may help prevent development of virus that is resistant (no longer responds) to nevirapine.

Studies show that some HIV-infected women can reduce their risk of passing the virus on to their babies by having a cesarean delivery before labor begins and their membranes have ruptured. The U.S. Public Health Service and the American College of Obstetricians and Gynecologists recommend that HIV-infected women be offered a cesarean delivery at 38 weeks to further reduce the risk to their babies, unless they have very low (less than 1,000 copies/mL) or undetectable amounts of the virus in their blood (7, 8). It is not yet certain whether a cesarean delivery further reduces the risks when a woman has very low or undetectable amounts of the virus in her blood as a result of drug treatment (7, 8).  

Doctors can recommend other precautions to help protect the baby. A doctor who knows that a woman is HIV-positive can avoid using procedures that could increase the exposure of the baby to the mother's blood during pregnancy or labor, such as amniocentesis, fetal-scalp blood sampling or rupturing the membranes. Doctors also can advise the woman not to breastfeed her baby, because breastfeeding also can transmit the virus to the baby. (This recommendation may differ in developing countries for a number of reasons.)

What are the symptoms of AIDS in babies?
HIV-infected babies appear normal at birth, but about 15 percent of untreated babies develop serious symptoms or die in the first year of life (9, 10). Before combination drug treatment, about half of HIV-infected children died by age 9 (10). Now more than 95 percent of treated children survive to at least 16 years of age (10). Many are free of serious symptoms much of the time.

Babies of women with HIV should be tested for the virus within 48 hours of birth (9, 10). These early tests, which detect the virus itself instead of the antibodies, can identify about 40 percent of infected newborns (9). Doctors generally repeat the test, allowing identification of most infected babies by one month, and virtually all by six months (9).

(The HIV screening test, which tests for antibodies to the virus, is not reliable for an infant born to an infected mother. This is because the mother's antibodies may be present in her baby's blood for up to 18 months, even if the baby has not been infected.)

The U.S. Public Health Service recommends that all infants with symptoms of HIV be treated with a combination of HIV-fighting drugs (9). Drug treatment should also be considered for HIV-positive babies who do not have symptoms because the disease tends to progress more rapidly in infants than in older children and adults. Studies show that combination therapy slows the progress of the disease and improves survival in infected babies and children, as it does in adults.

Most adults with AIDS suffer “opportunistic” infections, which rarely occur in people whose immune systems are not weakened. A child with AIDS is at special risk of serious illness from common bacteria. But early diagnosis of HIV infection and frequent follow-up can help prevent or reduce the severity of some infections.

One opportunistic infection common in both babies and adults with AIDS is Pneumocystis carinii pneumonia. Often this is the first AIDS-related illness to appear in infants and is a major cause of death in the first year of life. The U.S. Public Health Service recommends that a baby born to an HIV-positive mother (even if the baby has not yet been diagnosed with HIV or AIDS) be treated, beginning at four to six weeks of age, with drugs that help prevent pneumonia (9). The doctor will stop the medication if tests show the baby is not HIV-positive.

Babies with HIV infection should receive all routine childhood immunizations, plus some additional ones. The chickenpox vaccine, however, should be avoided in children with serious symptoms (though it is usually recommended for children with no or mild HIV symptoms) (9, 10). Babies with HIV/AIDS should be vaccinated yearly against influenza starting at seven months of age, and should receive the conjugated pneumococcal vaccine in the first year.

What steps can a pregnant woman take to remain uninfected?
Women should avoid all possible sources of infection before and throughout pregnancy, including

• Needles, razors or other items possibly contaminated with the blood of an infected person
• Sexual contact with someone who is infected

If there is any question about a partner's HIV status, proper use of condoms helps protect against HIV and other sexually transmitted diseases.

Where is HIV testing available?
Private doctors, local health departments, hospitals and clinics all offer HIV testing, as do sites set up specifically for this purpose. The CDC provides information and referrals to local testing sites:

• Through its toll-free telephone hotline at (800)-CDC-INFO (232-4636)

• On the Web

This includes information on free and anonymous testing. State and some local governments also provide hotlines for information about HIV/AIDS services.

Where can health care professionals get more information?
The American College of Obstetricians and Gynecologists offers information on perinatal HIV on its Web site.

The National Perinatal HIV Consultation and Referral Service at (888) 448-8765 provides free 24-hour clinical consultation and advice on:

• Treatment of HIV-infected pregnant women and their infants

• Indications and interpretations of rapid and standard HIV testing in pregnancy

References

1. Centers for Disease Control and Prevention (CDC). Mother-to-Child (Perinatal) HIV Transmission and Prevention. CDC, May 2006.
2. Centers for Disease Control and Prevention (CDC). HIV/AIDS Surveillance Report 2004, volume 16, 2005.
3. Connor, E.M., et al. Reduction of Maternal-Infant Transmission of Human Immunodeficiency Virus Type 1 With Zidovudine Treatment. New England Journal of Medicine, volume 333, number 18, 1994, pages 1173-1180.
4. Centers for Disease Control and Prevention (CDC). Revised Recommendation for HIV Testing of Adults, Adolescents, and Pregnant Women in Health-Care Settings, Morbidity and Mortality Weekly Report, September 22, 2006, volume 55, No. RR-14.
5. World Health Organization (WHO). Taking Stock: HIV in Children. WHO, 2006.
6. Centers for Disease Control and Prevention (CDC). HIV/AIDS Among Women. CDC, April 2006.
7. U.S. Department of Health and Human Services. Public Health Service Task Force Recommendations for Use of Antiretroviral Drugs in Pregnant HIV-1-Infected Women for Maternal Health and Interventions to Reduce Perinatal HIV-1 Transmission in the United States. October 12, 2006.
8. American College of Obstetricians and Gynecologists (ACOG). Scheduled Cesarean Delivery and the Prevention of Vertical Transmission of HIV Infection. ACOG Committee Opinion, number 234, May 2000.
9. Working Group on Antiretroviral Therapy and Medical Management of HIV-Infected Children. Guidelines for the Use of Antiretroviral Agents in Pediatric HIV Infection. November 3, 2005.
10. American Academy of Pediatrics (AAP). Human Immunodeficiency Virus Infection. Red Book: 2006 Report of the Committee on Infectious Diseases, 27th edition. Elk Grove, IL, 2006.

November 2006