OBJECTIVE: Concerns about including pregnant women in research have led to a dearth of evidence to guide safe and effective treatment and prevention of HIV in pregnancy. To better understand why these evidence gaps persist and inform guidance for responsible inclusion of pregnant women in the HIV research agenda, we aimed to learn what HIV experts perceive as barriers and constraints to conducting this research. METHODS: We conducted a series of group and one-on-one consultations with 62 HIV investigators and clinicians to elicit their views and experiences conducting HIV research involving pregnant women. Thematic analysis was used to identify priorities and perceived barriers to HIV research with pregnant women. RESULTS: Experts discussed a breadth of needed research, including safety, efficacy, and appropriate dosing of: newer antiretrovirals for pregnant women, emerging preventive strategies, and treatment for coinfections. Challenges to conducting research on pregnancy and HIV included ethical concerns, such as how to weigh risks and benefits in pregnancy; legal concerns, such as restrictive interpretations of current regulations and liability issues; financial and professional disincentives, including misaligned funder priorities and fear of reputational damage; and analytical and logistical complexities, such as challenges recruiting and retaining pregnant women to sufficiently power analyses. CONCLUSION: Investigators face numerous challenges to conducting needed HIV research with pregnant women. Advancing such research will require clearer guidance regarding ethical and legal uncertainties; incentives that encourage rather than discourage investigators to undertake such research; and a commitment to earlier development of safety and efficacy data through creative trial designs.