SIDA & VIH
HIV testing in pregnancy
Why test in pregnancy?
The principal purpose of testing a woman for HIV during pregnancy is to prevent any possible infection being passed to her unborn child. Mother to Child Transmission (MTCT) can occur during pregnancy, during labour and birth or through breastfeeding. However, with appropriate treatment and intervention, the chances of a child becoming infected can be reduced from around 25% to less than 2%.
AVERT.org has more about MTCT on our Mother To Child Transmission page. We are also running a campaign to call for better prevention of MTCT around the world.
These days, in areas where antiretroviral therapy is available, testing in pregnancy also allows for the mother's infection to be identified and treated. This will enable her to remain healthy enough to care for her baby and see her child grow up.
For many women, 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 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.
There are two different forms of routine testing: opt-out and opt-in.
Opt-out
In an increasing number of countries, including the UK and many US states, routine testing is now offered on an 'opt-out' basis. That means that all 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 that receives a 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.1 2 3
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. Generally 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 that 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.
In some countries (particularly those with limited resources), HIV testing is not routinely offered as part of national prenatal care programmes at all. However, internationally funded MTCT programs are now being set up in many developing countries, and HIV testing in pregnancy is on the rise.
What actually happens when a woman goes for 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.
What options other than voluntary testing are there?
On a sliding 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, you have 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+ 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 only country currently actively seeking to make HIV testing for pregnant women mandatory is Singapore, although the bill that would enforce mandatory testing has not yet been passed. Mandatory testing is useful, in that it can help prevent MTCT by identifying all women at risk of transmitting HIV to their babies, but 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.
Testing during pregnancy in the US
In 1990 over 2000 babies were born with HIV in the United States, with 900 of these cases occurring at the centre of the epidemic, New York City. By 2003 however, the annual total of babies born with HIV in the US was less than a tenth of 1990 figures, and just five babies were diagnosed in New York.4 Such statistics are impressive, particularly when you consider that opt-out voluntary testing is not universal across the US. However, some have questioned the methods used to achieve them.
At present the Centre for Disease Control in the US recommends voluntary counselling and testing (VCT) for all pregnant women.5 However it is up to individual states to make the final decision on whether this recommendation is implemented or not. Most follow guidelines and offer voluntary opt-out testing, but some still offer only basic provisions. Others, such as New York, have screening programmes in place that go beyond the recommendations issued by the CDC.
Mandatory testing of newborns
In New York (and also Connecticut), every newborn baby has a mandatory HIV test if the mother has not had a test during her pregnancy.6 While this may help to identify babies at risk of HIV, it also 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 around six weeks old.
Third, all babies found to have HIV antibodies would be given the drug AZT, 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.
Rapid testing during labour
As most MTCT occurs during labour and delivery, testing newborns is often too late for many preventative interventions. In those areas where voluntary opt-out testing is not routinely offered, or where women may not have had access to primary care during their pregnancy, rapid testing may therefore be offered in the delivery room.
HIV testing during labour is recommended practice in the UK for anyone who has not received a test in pregnancy.
In November 2001, a five-year study known as MIRIAD (Mother Infant Rapid Intervention at Delivery)7 was set up in the US to assess the feasibility of testing during labour. The programme is currently running in five states, and has proved so effective at identifying unknown cases of HIV, that voluntary testing during labour was adopted as standard practice in one of the study centres, New York State, in 2003.8
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 AZT to be administered during labour and delivery.
However, although rapid testing 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 a 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.
According to guidelines from the British HIV Association9, testing during labour is also recommended practice in the UK for anyone who has not received a test in pregnancy, but it is not known how frequently this practice is implemented.
Testing in 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%.10
Antenatal screening can be difficult to implement in resource poor settings for a number of reasons:
- 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 200511 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.
