OBJECTIVES When you have completed this unit you should be able to: Assess the risk of HIV transmission from a mother to her fetus. Describe how pregnant women can be screened for HIV infection. List which pregnancy complications are commoner with HIV infection. Diagnose AIDS in pregnancy. Use zidovudine to reduce the risk of vertical transmission. Manage a pregnant woman with HIV infection or AIDS.

COPYRIGHT

All rights reserved. No part of this Perinatal Education Programme may be altered in any way without the written permission of the editorial board of the Perinatal Education Trust. To facilitate the improvement of perinatal care, the Programme may be reproduced for teaching purposes provided due acknowledgement is given and the material is not sold for financial profit. While the advice and information in the Programme is believed to be accurate, the editorial board cannot accept responsibility or liability for any errors or omissions that may have been made.

ISBN 0 7992 1955-X

32-1 IS HIV INFECTION COMMON IN PREGNANT WOMEN?

In Africa, where HIV infection is usually spread by sexual intercourse, HIV is more common in women than in men. In South Africa in 1990 less than 1% of pregnant women were HIV positive. By 2004, more than 25% of all pregnant women were infected with HIV. The rates of infection vary widely from region to region. In some regions up to 40% of all pregnant women are HIV positive. About 250 000 HIV women become pregnant in South Africa each year.

32-2 SHOULD PREGNANT WOMEN BE SCREENED FOR HIV?

Yes. Easy to use and affordable rapid tests have become widely available in both public and private health care facilities. Benefits of HIV screening are:

1. The transmission of HIV transmission to the fetus and infant during pregnancy, labour and delivery can be reduced.
2. The mother can decide whether to breast or formula feed her infant.
3. Women who are HIV negative can be reassured and be advised to practice safer sex.
4. Women with AIDS and its complications can be promptly diagnosed and managed.
5. Infants born to HIV positive women can be correctly managed.
6. The risks of future pregnancies can be discussed.
7. Women can be warned of the risk of passing HIV on to their partner.

HIV infection in women is often diagnosed for the first time when they are screened during pregnancy.

ALL PREGNANT WOMEN SHOULD BE OFFERED HIV SCREENING

32-3 HOW MAY PREGNANT WOMEN BE SCREENED FOR HIV INFECTION?

A blood test is used to screen for antibodies to HIV. The presence of HIV antibodies in an adult or child older than 18 months indicates the presence of HIV infection. A number of tests are available to screen for HIV antibodies. Usually the ELISA (enzyme-linked immunosorbent assay) or rapid tests are used. These are highly accurate tests. Two positive tests, using kits from two different manufacturers on two separate blood samples, are needed before a definite diagnosis of HIV infection is made, in order to be sure that the diagnosis is correct.

32-4 CAN HIV BE TRANSMITTED FROM A PREGNANT WOMAN TO HER FETUS?

Yes. HIV can cross the placenta from mother to fetus at any time during pregnancy. Without antiretroviral prophylaxis, the risk is about 5%. However, most fetal infection during pregnancy takes places in late pregnancy or during labour. The combined risk of HIV transmission to the fetus during pregnancy, labour and delivery is about 20% if antiretroviral prophylaxis is not used. The spread of HIV from a mother to her fetus or infant is called mother-to-child transmission (MTCT) or vertical transmission. Avoiding vertical transmission is one of the most important methods of preventing the spread of HIV in a community. In women who do not breastfeed, most vertical transmission takes place soon before or during labour.

*** HIV has been found as early as 8 weeks of gestation in aborted fetuses. First trimester HIV infection may cause abortion and be more common than is presently believed.

32-5 WHICH HIV POSITIVE WOMEN ARE AT HIGH RISK OF INFECTING THEIR INFANTS WITH HIV DURING PREGNANCY?

All HIV positive women can infect their fetus. However, the following women have the greatest risk of transmitting HIV to their fetus:

1. Women who become infected with HIV during that pregnancy.
2. Women with clinical AIDS.
3. Women who are undernourished, especially women with vitamin A deficiency.
4. Women who do not have antiretroviral prophylaxis.

Women who become infected during pregnancy and women with AIDS have high viral loads that increase their risk of vertical transmission of HIV. It has been suggested that women who have an antepartum haemorrhage and women who have amniocentesis may also have a higher risk of transmitting HIV to their infants.

*** Women with low levels of anti-HIV antibodies may be at an increased risk of transmitting HIV to their infants.

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