HIV testing in pregnancy

Sunday 6 June 2010 by Children ·

In many countries across the world, women are tested for HIV during pregnancy. There are a number of important reasons for this:

  • HIV infection can be passed on to a baby during pregnancy, labour and delivery, and breastfeeding. With appropriate treatment and intervention, the chances of a child becoming infected can be reduced from around 25% to less than 2%. It is therefore vital that an HIV infection in a mother is identified during the early stages of pregnancy to allow for an opportunity to reduce the risk of transmission to the baby. AVERT.org has more information about mother-to-child transmission (MTCT), including details of a Stop AIDS in Children campaign, which is calling for better prevention of MTCT around the world.
  • In areas where antiretroviral therapy is available, a pregnant woman can receive these drugs if she tests HIV positive during pregnancy. The antiretroviral drugs can suppress HIV, which will keep her healthy for longer.
  • For many women, especially in resource-poor areas, pregnancy will be the only time in their young adult lives when they access healthcare services on a regular basis. It therefore presents an excellent opportunity not only to screen for HIV, but also to educate and advise about the dangers of the virus.

Routine, voluntary HIV testing

In most developed nations, HIV tests are either routinely offered as part of antenatal care or are offered to pregnant women thought to be at high risk of exposure to HIV. This has helped to reduce rates of mother-to-child transmission dramatically.1 There are two types of routine testing: opt-out and opt-in.

Opt-out

Kenyan poster promoting HIV counselling and testing for pregnant women
A Kenyan poster promoting HIV counselling and testing for pregnant women
In an increasing number of countries, including the UK and many US states, routine testing is now offered on an 'opt-out' basis. This means that all pregnant women receive an HIV test, unless they specifically state that they do not want one. Before testing, all women are given information about what HIV is, what the test is for and how it will be carried out. Any woman who receives an HIV positive result will then be counselled and given appropriate treatment if necessary. Studies in developed countries have shown that when pregnant women are offered a routine HIV test with counselling, around 85-95% agree to have one.2 3 4

Opt-in

With opt-in testing, a woman may be informed that a test is available, but they will only be given one if they specifically request it. Often this means that only women who are worried about HIV (perhaps because they fit into a 'high-risk group') will agree to be tested. Opt-in testing is generally considered less effective than opt-out. Many women believe they simply don't need a test, or fear that the midwife or doctor will make assumptions about their levels of 'risky' behaviour if they ask for one. This means uptake tends to be much lower.5
In some countries (particularly those with limited resources), HIV testing is not routinely offered as part of national prenatal care programmes at all. In 2007 it was reported that (where data was available), just under a fifth of pregnant women in low- and middle-income countries received an HIV test.6 However, in recent years there has been increased focus on MTCT and in some areas testing uptake has nearly doubled.7

What options other than voluntary testing are there?

On a scale of the level of intervention women face during pregnancy, routine opt-out testing is generally considered to be somewhere in the middle. It is common, acceptable to most, and it works, without infringing on a woman's rights. At either end of this scale however, are two vastly contrasting strategies. One is the option of no intervention at all, which can lead to high levels of MTCT, and a large population of HIV positive children. The other is mandatory testing.
Mandatory testing is different from voluntary testing because the mother has no choice over whether she gets tested or not. She is bound by law to be tested and no consent is required.
The ethics of mandatory testing are frequently debated. Mandatory testing can be useful, in that it can help prevent MTCT by identifying all women at risk of transmitting HIV to their babies. However, it also removes a woman's right to give informed consent. This could have implications for women who do not wish to be informed (and thus have their partners told, too) because they fear the repercussions for themselves or their babies. It could also mean that women are put off accessing health care services, because they worry that their status will be forcibly disclosed.

What happens when a pregnant woman goes for HIV testing?

In the UK, HIV testing is carried out at the first meeting with the midwife, at around the 10-12th week of pregnancy. Each country that has an opt-out voluntary HIV testing policy will have a slightly different way of implementing it, but the basic principles are the same. Blood will be taken, and this blood will be screened for HIV, usually at the same time that a full blood count is taken and rubella antibodies, hepatitis B and syphilis infection are tested for. Information or a leaflet will usually be given, explaining exactly what is being tested for and why. A woman will then be asked if she consents to all the tests. If she has any objections, this will either be noted on her form by the midwife or doctor, or she will be asked to sign an official disclaimer confirming her refusal. Post-test counselling will be offered to all women when they receive their test result, regardless of whether it is positive or negative.

HIV testing during pregnancy in the United States

At present the Centre for Disease Control in the United States recommends universal routine screening early in pregnancy for all pregnant women, on an 'opt-out' basis.8 However it is up to individual states to make the final decision on whether this recommendation is implemented and currently only 22 states have opt-out guidelines.9
During 1988 and 1993 in the US, an estimated 1000-2000 children became infected with HIV each year through mother-to-child transmission.10 By 2006, this number had dramatically decreased and just over 100 babies were infected through MTCT (in the 33 states that reported data).11 Such statistics are impressive, particularly when opt-out voluntary testing is not universal across the US. However, some have questioned the methods used to achieve them.

Rapid HIV testing during labour

The CDC recommends rapid HIV testing during labour, if the woman's HIV status is unknown.12 The rapid test used is an HIV antibody test that gives a result within 20-40 minutes. A positive result allows for safer delivery practices to be adopted, and for appropriate antiretroviral drugs to be administered during labour and delivery.
“Although rapid testing during labour can ensure HIV positive pregnant women receive treatment quickly, there are questions over how ethical it is.”
However, although rapid testing during labour can ensure HIV positive pregnant women receive treatment quickly, there are questions over how ethical it is. To give informed consent for an HIV test you must have been given proper counselling so you understand what having a test involves and what the consequences are if you test positive. Time must also be given for the woman being tested to think of and ask any questions she may have, and counselling must be initiated after the result is given. Most mothers and midwives would agree that when a woman is in labour, it is unlikely that she will be in any state to give informed consent, or to cope emotionally with a positive result. Testing earlier in pregnancy is therefore still recommended as the principle method of HIV identification.

Mandatory HIV testing of newborns

If the mother's HIV status is still unknown after birth, CDC guidelines recommend rapid testing of newborns as soon as possible to allow for immediate initiation of antiretroviral prophylaxis.13 Currently ten US states implement newborn testing, but on a mandatory basis.14  Some states allow parents to refuse the test on religious grounds. This mandatory testing policy raises a number of ethical issues.
First, testing newborn babies discloses the mother's HIV status without her giving consent. Second, it doesn't conclusively show the baby's HIV status, as all babies born to HIV positive mothers have HIV antibodies. Babies who are uninfected don't lose their antibodies until the age of 18 months and around 75% of babies with HIV antibodies are actually uninfected by the virus. A PCR test that detects the actual presence of viral DNA can also be done, but cannot give an accurate result until a baby is around six weeks old. Third, babies found to have HIV antibodies would be given antiretroviral drugs, which may prevent HIV developing, but may also potentially have detrimental effects in the long term because of its toxicity. If a mother objects to this, she risks legal action, and may even have her baby removed from her care.

HIV testing during pregnancy in high prevalence areas

Routine voluntary testing in pregnancy is advisable anywhere, but for developing countries at the heart of the AIDS epidemic, it is an essential step in preventing MTCT and the onward spread of HIV. Non-governmental organisations and charities have long been helping to run complete programmes to prevent mother to child transmission in developing countries, but their work is often restricted to small areas or individual hospitals. Government-implemented nationwide screening programmes are therefore necessary to provide universal coverage. Until recently, the uptake of routine voluntary testing in resource-poor countries was low, but progress is now being made. In Botswana for example, opt-out voluntary testing similar to that available in Western nations has been in place since 2004, and uptake has so far been around 90%.15
Antenatal screening can be difficult to implement in resource poor settings for a number of reasons:
'Help protect your baby from HIV' campaign poster
'Help protect your baby from HIV' campaign poster, South Africa
  • Monetary constraints can mean that it is simply not financially viable to provide tests for every pregnant woman
  • Stigma and discrimination can be severe in certain areas, and many women fear people will discover their status if they take a test.
  • Lack of education can make doctors and midwives more wary of women with HIV, particularly if standard universal precautions (such as surgical gloves) are not available during delivery. This can in turn make women reluctant to find out their status in case they are treated differently or are refused care.
  • Lack of drugs, specialist care or breast milk formula to actually prevent MTCT can lead to the belief that testing for HIV is a waste of time.
However, when fully informed of the benefits of testing, many women in high prevalence areas are more than willing to receive a test. A study carried out in Zimbabwe in 200516 for example, found that out of 285 women, 55% had actually been tested for HIV in pregnancy, but 80% would be willing to take the test. This led the investigators to recommend that 'opt-out' voluntary testing should be introduced across the country.

References

  1. Maheswaran, H & Bland, R.M (2009) 'Preventing mother-to-child transmission of HIV in resource-limited settings', Future Virology, 2009;4(2):165-175.
  2. Schuman, Paula et al. 'Voluntary HIV Counseling and Testing of Pregnant Women -- An Assessment of Compliance With Michigan Public Health Statutes', Medscape General Medicine, 16 June 2004, Vol. 6 No. 2
  3. Simpson, Wendy M. 'Antinatal HIV Testing: Assessment of a routine voluntary approach', BMJ, 19 June 1999, Vol. 318 No. 7199
  4. Bitnun,Ari et al.'Failure to prevent perinatal HIV infection', Canadian Medical Association Journal, 02 April 2002; Vol. 166 No. 7
  5. MMWR (2002) 'HIV testing among pregnant women - United States and Canada 1998-2001', November 15, 2002/51(45) 1013-1016
  6. UNICEF (2008, December) 'Children and AIDS: Third stocktaking report, 2008'
  7. UNICEF (2008, December) 'Children and AIDS: Third stocktaking report, 2008'
  8. MMWR (2006) 'Revised recommendations for HIV testing of adults, adolescents, and pregnant women in health-care settings', September 22, 2006/55;1-17
  9. Kaiser Family Foundation (2008) 'HIV testing for mothers and newborns, February 2008', www.statehealthfacts.org
  10. MMWR (1996) 'AIDS among children - United States, 1996', November 22, 1996/45(46);1005-1010
  11. CDC (2006) 'HIV/AIDS surveillance report', Vol. 18
  12. MMWR (2006) 'Revised recommendations for HIV testing of adults, adolescents, and pregnant women in health-care settings', September 22, 2006/55;1-17
  13. MMWR (2006) 'Revised recommendations for HIV testing of adults, adolescents, and pregnant women in health-care settings', September 22, 2006/55;1-17
  14. Kaiser Family Foundation (2008) 'HIV testing for mothers and newborns, February 2008', www.statehealthfacts.org
  15. MMWR (2004) 'Introduction of routine HIV testing in prenatal care - Botswana 2004', 53(46);1083-1086
  16. Perez, F et al (2005) 'Acceptability of routine HIV testing in antenatal services in Zimbabwe' International AIDS Society

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