Objectives To compare the environmental health results in women trying to get pregnant or pregnant using a mobile health application (Green Page) through healthcare professionals or self-completed by women, and to explore the relationship between the subjective well-being of these women with their lifestyles and environmental factors. Methods A descriptive study with mixed methods was conducted in 2018. A mobile health survey was used in two phases. Phase 1 was a cross-sectional study through professionals ( n = 1100) followed by phase 2, a convenience sampling through women's self-reporting ( n = 3425). A personalized report was downloadable with health recommendations for the well-being of the mother and child. Results Of the 3205 participants (mean age = 33 years, SD = 0.2 years), 1840 were planning a pregnancy and 1365 were pregnant. One in five pregnant women had a low level of happiness. Globally, subjective well-being and happiness were found to be negatively associated with lack of contact with nature, sedentary lifestyle, excess weight, environmental exposure, and older age in pregnancy. Precisely 45%, 60%, and 14% of women were exposed to tobacco, alcohol, and illegal drugs, respectively. The women self-reported levels of risk factors higher than when the tool was used by or through professionals. Conclusions The use of mobile health interventions focused on environmental health during planning or pregnancy periods could help improve the quality of healthcare and foster greater involvement of women in their self-care process, thus promoting empowerment, healthier environments, and lifestyles. Ensuring equity of access and data protection are global challenges to be addressed.