Previous studies conducted by different researches all indicated that without the use of anti-retroviral drugs, pregnancy showed either no increased risk of AIDS progression or a slightly increased risk.
A new study found that pregnancy along with anti-retroviral therapy could help protect HIV-positive women from AIDS progression and minimize death risk.

In this observational study that looked at 759 women at some point of the study period, women who became pregnant were healthier than the women who did not get pregnant, they had a higher count of immune system cells and a lower viral load.

It is still not known why pregnant women had better results but researchers believe that their immune systems were working better.
Study researchers suggest that the benefits could be due to the fact that pregnant women were more motivated to have their HIV treated, prevent HIV transmission to the fetus and take good care of themselves. It is very likely that additional motivation facilitated them in doing better.

Further more, pregnant women infected with HIV received more intensive care at the comprehensive care centers, had more frequent visits, received more dietary supplements, and were less likely to abuse drugs.
These factors could have played a role in them doing much better than the women who did not get pregnant.

Another study is needed to try to formally pinpoint the reason for the benefit.