Pregnancy Among HIV-Serodiscordant Couples: Case Report of Vertical Transmission and Retrospective Case Series.

Background HIV transmission during pregnancy and breastfeeding among serodiscordant heterosexual couples represents an ongoing barrier to elimination of vertical transmission of HIV-1 infection in Canada. Objective To report a case of vertical HIV transmission during breastfeeding and examine the prevalence of risk factors for HIV transmission in the pregnancy and postpartum periods among serodiscordant couples where the male partner is HIV positive and female partner HIV negative. Methods Case report and retrospective chart review of HIV-serodiscordant pregnant couples over an eight-year period in Edmonton, Canada. Results We report a case of maternal primary HIV infection during the postpartum period and vertical transmission to a nursing infant that went undetected until the infant presented with AIDS. We also report a series of 41 serodiscordant pregnant couples identified by our public health nurse between 2008 and 2016. Among HIV-infected male partners, 20 (49%) had detectable viral load (VL) during their partner's pregnancy and during breastfeeding, with median peak VL 4,700 copies/mL (range 49-120,000) and 5,100 copies/mL (range 40-120,000) during pregnancy and breastfeeding, respectively. None of the female partners seroconverted during pregnancy, but three seroconverted at 1.8, 2.4, and 6.9 years after delivery. No vertical transmission occurred. Conclusion Despite concerted attempts to minimize HIV transmission during pregnancy and breastfeeding in our wellresourced setting, residual transmission risk remains due to non-suppressed viral load within many HIV-serodiscordant pregnant couples.