HIV in Pregnancy: What a Mother-To-Be Should Know

Being pregnant as an HIV-positive woman doubles the concerns. What are the risks of the baby being infected during and after the pregnancy? Are medications safe enough for fetal development and, at the same time, effective enough to prevent disease progression? This article will dive into different aspects of this important topic.

Although 50% of people worldwide with human immunodeficiency virus (HIV) are women, a significant number of them are diagnosed during pregnancy screening tests. Being previously or newly diagnosed, having a planned or unplanned pregnancy, and having the desire to continue the pregnancy: all these factors will affect the decision-making process.

Transmission of HIV to the baby

If the baby receives HIV from the infected mother, this way of getting the infection is called vertical transmission.

Several factors may affect the transmission risk:

• HIV RNA levels. HIV RNA levels below 1000 copies/mL decreases the vertical transmission risk. However, even with low RNA levels, there is around a 1% transmission risk. This risk might be associated with trace amounts of HIV in vaginal secretions.
• Antiretroviral treatment (ART). With advancements in HIV treatment options, in the countries with access to the resources, the infection rate of newborn babies is less than 1%. The historical AIDS Clinical Trial 076 showed that the women treated with the antiretroviral drug zidovudine transmitted disease to their babies three times less than the women who did not receive treatment.

How to prevent vertical transmission?

Vertical transmission may happen in different stages: during pregnancy, labor, delivery, or breastfeeding. As all these steps can potentially infect the baby, preventative measures should be considered at all levels.

In utero prevention

The time of treatment initiation is the main factor in decreasing the risk during pregnancy.

A study from France showed that women diagnosed and subsequently received anti-HIV drugs during pregnancy experienced vertical transmission more than those who started treatment during conception (0.99% vs. 0.14%).

Another study analyzing more than a thousand women showed that if treatment is delayed to the 28th week of gestation or later, this therapy may not be efficient for complete viral suppression.

Therefore, early diagnosis and treatment initiation are crucial to prevent in utero HIV transmission, and as a standardized practice, most healthcare systems screen women for HIV during their pregnancy.

Prevention during labor and delivery

During vaginal delivery, the baby might get in contact with the virus in vaginal secretions. It might be a potential source of vertical transmission.

If complete viral suppression has not been achieved (if lab results indicate >1000 copies per mL), a C-section is recommended at the 38th gestational week.

Results from two measurements will aid in deciding the delivery time and mode:

1. The accurate pregnancy date assessed in the first trimester
2. Plasma viral load evaluated at 34–36 weeks.

Prevention during breastfeeding

Cell-free virus and HIV-infected maternal cells can be found in breast milk. Thus, breastfeeding introduces a risk of transmission after delivery.

The transmission rate is lower in non-breastfed infants than in breastfed babies. Reports of infection in babies born to HIV-negative mothers and breastfed by HIV-positive surrogate mothers also support the vertical transmission risk.

Findings from the Breastfeeding and HIV International Transmission Study and several cohort studies suggest that the highest breastfeeding transmission risk is observed in the earliest months of the babies life. Nonetheless, at 18 months of life, transmission risk with breastfeeding is still 9.3%.

Replacement feeding is one of the recommended protection alternatives.

For several years, various studies, including WHO recommendations, supported the idea that shortened breastfeeding, i.e., weaning at 4–6 months, may reduce the transmission rate. However, abrupt breastfeeding cessation was not effective in preventing newborn infections.

Combining breastfeeding with liquid and solid foods was considered another preventive method. Interestingly, several studies from South and West Africa found that mixed feeding increases the HIV transmission rate.

Maternal antiretroviral therapy (ART) and infant anti-HIV prophylaxis reduce the transmission risk the most. The WHO recommends that HIV-positive mothers continue ART treatment during breastfeeding. Breastfeeding should be exclusive during the first six months and continue with appropriate complementary food for up to 24 months or longer, not different from the general population.

Infant antiretroviral prophylaxis

According to the HIV/AIDS panel by the National Institute of Health (NIH), newborns exposed to HIV infection but not infected should receive one or more ART drugs as prophylaxis. If the newborn is also diagnosed with HIV, then ART with a three-drug regimen should be initiated.

Are ART drugs safe for the babies?

All HIV-diagnosed women should be treated with ART to treat the disease, prevent its progression, and protect babies from transmission. However, pregnancy increases concerns about treatment choices.

Several studies indicated a certain level of relationship between some side effects and ART drugs:

However, with the current information, the literature is inconsistent or limited about the complications, and further studies will be required for more evidence. At the same time, with the advancing and rapidly changing treatment options, there is no long-term data on how safe ART drugs are for the fetus.

Detailed information on ART drug safety can be found in the guidelines by the US Department of Health and Human Services.

In conclusion, lifelong ART is recommended for all HIV-positive women, including pregnant ones. ART treatment initiated as early as possible suppresses viral load and decreases the transmission risk most effectively. It is understandable that mothers might worry about the drug's effects on the forming embryo and may want to avoid treatment during the first trimester. However, medical literature recommends not delaying the treatment for better viral control.