This is an application for an administrative supplement to a current NIMH R01 study that was severely affected by the COVID-19 pandemic. Despite the potential for antiretroviral therapy to improve maternal health and reduce mother-to-child transmission of HIV to as low as 1%, HIV-related maternal deaths and HIV infection among infants remain unacceptably high across sub-Saharan Africa. This is particularly true in Kenya, where crucial drop-offs occur in the cascade of prevention of mother-to-child transmission (PMTCT) services. Weak health systems contribute to insufficient service coverage, but many barriers lie beyond the clinic—in the partner, family, and community factors that shape women’s health decisions. Our team’s research in a high HIV prevalence area of southwestern Kenya has shown that many women avoid couples HIV testing and do not adhere to PMTCT regimens because they fear negative consequences from a male partner. Men can play a crucial supportive role for family health, but male partners in Kenya are poorly engaged in antenatal care and uptake of couples HIV testing during pregnancy is low. Pregnant women desire to be tested for HIV together with their partner and need the support for mutual disclosure involved in couples HIV testing and counseling (CHTC), regardless of whether they know their own HIV status. In this context, we are testing the efficacy of an interdependence theory-based couples intervention that reaches pregnant women and male partners through home visits by male-female pairs of lay health workers, and includes offer of home-based CHTC services. We are conducting a robust investigation to determine whether this intervention improves uptake of couples HIV testing and health outcomes over and above less intensive male engagement strategies being used in the region. We are conducting a three-arm trial among 800 pregnant women and partners, randomizing them to home- based couple visits, HIV self-test (HIVST) kits to use with their male partner, or standard care, following couples up to 18 months postpartum. In Aim 1, we are determining the effects of the intervention on our primary outcome of couple HIV testing, compared to HIVST kits and standard care. In Aim 2, we are examining intervention impact on HIV prevention behaviors, facility delivery, and postnatal healthcare utilization. Among couples living with HIV, secondary outcomes include maternal VL suppression and HIV-free child survival up to 18 months. In Aim 3, we are comparing the cost-effectiveness of the home-based couples intervention to the less resource- intensive strategies used in the other two study arms. Due to restrictions on in-person research posed by the COVID-19 pandemic we completed enrollment of 800 couples more than one year later than planned, and will not be able to complete intervention delivery and follow-up of the sample with the originally allocated time frame and funds. This administrative supplement is necessary to be able to achieve ...