One of the ways that HIV infection can be transmitted is during pregnancy, from mother to baby. The virus is present in the blood, and it can cross the placenta into the baby’s body. This is why it’s important for a pregnant woman to be aware of her HIV status, so that she can protect her unborn child from this virus during the pregnancy and delivery.
Do doctors test for HIV during pregnancy? How accurate is this test? Can HIV transmission during pregnancy be prevented?
Are pregnant women tested for HIV?
The current recommendation is that all pregnant women be tested for HIV. The screening is generally done early in the pregnancy. This isn’t absolutely mandatory, and if you really don’t want to get an HIV test, then you certainly don’t have to. However, the CDC recommends HIV screening for pregnancy for all women, even if they don’t have any known risk factors. (Keep in mind that there are generally many blood tests throughout pregnancy anyway, so you won’t even need an extra blood draw to get the test.)
Many women don’t believe that they have any risk factors for HIV. However, exposure to HIV can sometimes occur unknowingly. For example, it’s possible that your partner got HIV from a previous partner and had no idea. There’s very little downside to getting an HIV test during your pregnancy, so even if the chance that you have the virus is tiny, it’s worth taking the test.
Can you get a false positive HIV test during pregnancy?
All medical tests can give false positives. A false positive would mean that the test shows that you have HIV, when really you don’t have it. This could create a lot of unnecessary anxiety during your pregnancy.
For the HIV test that is generally used for HIV screening during pregnancy, the specificity is 99.6%. This means that if a person who is actually HIV-negative takes the test, it will show a negative result 99.6% of the time. However, the other 0.4% of the time, the test will show a false positive. A false positive is not common, but it certainly does occur.
An HIV diagnosis is never made on the basis of a single test. If you test positive for HIV, then a follow up test will be performed to confirm the test results, before you’re diagnosed with HIV. If you don’t have risk factors and you test positive for HIV during your pregnancy screening, then chances are actually high that this is a false positive, and the follow-up test will provide you with peace of mind.
How accurate is the HIV test during pregnancy?
With any medical test, there is also the risk of a false negative. This means that the test misses a true HIV infection. Although a false positive can create unnecessary anxiety, a false negative HIV test during pregnancy could be truly dangerous, because it might result in a mother transmitting HIV to her baby.
For HIV, there is a period of time after exposure called the “window period.” During this time, the virus is still getting established in the body. The various markers that are used to test for infection have not yet had a chance to rise to high enough levels to be detected. The window period is between about 45 and 90 days, depending on the type of test used. If you test during the window period, you may get a negative test, even if you do have HIV. If you’re exposed to HIV shortly before or during your pregnancy, then you might be in the window period when you get your HIV screening early in your pregnancy. Testing again later in the pregnancy can help to confirm that you don’t have HIV.
Fortunately, false negatives are very rare after the window period, and occur only in 0.01% of cases. If you receive a negative HIV test after the window period has passed, there is almost no chance that you have HIV.
What are the HIV symptoms in pregnant women?
In general, HIV doesn’t cause many symptoms in most people until its late stages. When they first get the infection, some people experience a flu-like illness, with symptoms like fever, malaise, and muscle aches. However, these symptoms can be so mild that the patient doesn’t even notice them, and some people have no symptoms at all. Once this phase passes, HIV doesn’t cause any symptoms at all until it’s destroyed enough of the immune system that the patient starts to get strange infections.
If you acquire a new HIV infection during your pregnancy, then you might experience that early flu-like illness. However, it would be easy to miss these symptoms, especially when you’re already dealing with the many changes that pregnancy brings to the body. If you were exposed to HIV before your pregnancy, and the initial stage of infection has already passed, then there would likely be no symptoms at all.
How can a baby be protected from HIV during pregnancy?
HIV is transmitted from the mother’s blood to the baby’s blood. The best way to protect the baby is to reduce the amount of the virus in the mother’s blood during her pregnancy. This involves her taking HIV medications throughout the pregnancy. The goal is to achieve an undetectable viral load, meaning that the amount of virus in her blood is so low that tests can’t even detect it. In addition, the baby is given HIV medications for a few weeks after birth, in case a few viral particles made it into the baby’s body.
This method of preventing HIV transmission in pregnancy is very effective, and can reduce the risk of a baby acquiring HIV to 1% or even less. Since 1995, the number of HIV infections acquired by babies from their mothers during pregnancy has gone down by 95%. Besides protecting the baby during the pregnancy, this method also helps to protect the mother’s health, by preventing her HIV infection from progressing.
If the mother has a higher viral load during the late stages of pregnancy, then it’s recommended that the baby be delivered by Cesarean section (C-section). This helps to avoid mixing of mother’s blood and baby’s blood during delivery. However, if the mother’s viral load is very low, then vaginal delivery is considered safe.
Sources
False-Positive HIV Test Results. Centers for Disease Control and Prevention (2018). https://www.cdc.gov/hiv/pdf/testing/cdc-hiv-factsheet-false-positive-test-results.pdf. Accessed 16 March 2022.
HIV and Pregnancy. American College of Obstetricians and Gynecologists (2022). https://www.acog.org/womens-health/faqs/hiv-and-pregnancy. Accessed 16 March 2022.
HIV and Pregnant Women, Infants, and Children. Centers for Disease Control and Prevention (2022). https://www.cdc.gov/hiv/group/gender/pregnantwomen/index.html. Accessed 16 March 2022.
Huang X, Liu X, et al. Evaluation of Blood-Based Antibody Rapid Testing for HIV Early Therapy: A Meta-Analysis of the Evidence. Front Immunol 2018 Jun 26;9:1458. doi: 10.3389/fimmu.2018.01458.
Hurst SA, Appelgren KE, et al. Prevention of mother-to-child transmission of HIV type 1: the role of neonatal and infant prophylaxis. Expert Rev Anti Infect Ther 2015 Feb;13(2):169-81. doi: 10.1586/14787210.2015.999667.
Labor and Delivery Management of Women With Human Immunodeficiency Virus Infection. American College of Obstetricians and Gynecologists (2018). https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2018/09/labor-and-delivery-management-of-women-with-human-immunodeficiency-virus-infection. Accessed 16 March 2022.
