Careful planning may be the best strategy for safer conception

Benefits of PrEP as an adjunctive method of HIV prevention during attempted conception between HIV-uninfected women and HIV-infected male partners.

Hoffman RM, Jaycocks A, Vardavas R, Wagner G, Lake JE, Mindry D, Currier JS, Landovitz RJ. J Infect Dis. 2015 Jun 19. pii: jiv305. [Epub ahead of print]

Background: Data on effectiveness of preexposure prophylaxis (PrEP) for human immunodeficiency virus (HIV)-uninfected women attempting conception with HIV-infected male partners are limited to observational studies.

Methods: To explore the benefits of PrEP for conception, we developed a model to estimate the average annual probability of a woman remaining HIV-uninfected and having a child ("successful" outcome) via condomless sex with an HIV-infected male. The outcome likelihood is dependent upon parameters defining HIV-1 infectivity. We simulated 2 scenarios: optimal (condomless sex acts limited to the ovulation window), and suboptimal (acts not limited to ovulation).

Results: In the optimal scenario when the male is on antiretroviral therapy (ART), the average annual probability of the successful outcome is 29.1%, increasing to 29.2% with the addition of PrEP (P = .45). In the suboptimal scenario, the probability is 26.8% with ART alone versus 27.3% with ART/PrEP (P < .0001). Older maternal age reduces the probability of success in both scenarios, particularly after age 30.

Conclusions: In our model, PrEP provides little added benefit when the HIV-infected male partner is on ART, condomless sex is limited to the ovulation window, and other modifiable transmission risks are optimized. Older female age decreases the probability of success by increasing the number of condomless sex acts required for conception.

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Editor’s notes: Antiretrovirals (ARVs) have been shown in several studies to be highly effective in preventing both the acquisition of HIV in HIV negative individuals, and the transmission of HIV from HIV positive people to HIV negative people. However, the real-world application of these activities is still being investigated. This paper explores a strategy currently in discussion to use ARVs for safer conception in which the HIV negative partner might take pre-exposure prophylaxis (PrEP) and the HIV positive partner may be taking HIV treatment. The model employed in this paper looked specifically at the added benefit of the HIV negative woman taking PrEP. The results of the model illustrated that there was no added benefit of the woman taking PrEP if her HIV positive partner was taking HIV treatment consistently and they kept the number of condomless sex acts to the minimum required for the best chance of conception. Interestingly, as the woman in the model increases in age so do the number of condomless sex acts required to conceive, thus increasing the risk of acquiring HIV. While this paper illustrated that PrEP may not be worth the added expense, there may be situations where it still can provide added security to couples. Ultimately, models cannot completely account for what happens in real-life, and as the paper counsels, it will be up to physicians and their patients to decide what is best on a case by case basis. 

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