The exploration and exploitation of natural resources may interfere with using indigenous plants for food and medicine, including during pregnancy. However, this has not received deserving scientific attention in Nigeria, where crude oil mining is rigorously taking place in the Niger-Delta region. Using informant ethnobotanical surveys, we investigated for the first time the extent of the potential effect of crude oil exploration on Vernonia amygdalina (VA), the most widely used and valued plant, especially during pregnancy in Abraka and Kokori. A total of 82 participants comprising 22 Traditional Medical Practitioners (TMPs) and 60 from sundry professions in Kokori and Abraka were interviewed. Qualitative descriptive statistics were used to analyse respondents' data. Quantitative ethnobotanical indices were further used to quantify data generated from respondents. Results suggest VA is highly valued (UVI = 1.0), widely used during pregnancy (UMI = 0.98) and well cultivated in the study area (IC = 0.87). Respondents lamented that crude oil mining has negatively impacted VA (IPI = 0.596) and its efficacy (CEI = 0.354) over the years. Findings from this study calls for future in-depth scientific investigation of the potential impact of crude oil exploration and mining on medicinal plant biomass.