Regret, uncertainty, and bounded rationality in norm-driven decisions.

Menstruation is a natural biological process marking the transition from adolescence to womanhood. Despite its physiological normalcy, menstruation remains a subject of silence, stigma, and discrimination in many societies, particularly in low- and middle-income countries (LMICs) such as Nepal. Inadequate menstrual hygiene management (MHM) has been associated with negative health outcomes, including reproductive tract infections, urinary tract infections, and psychological distress. Moreover, it affects educational attainment, mobility, and the overall well-being of adolescent girls and women [–]. Globally, more than 500 million women and girls are estimated to lack access to adequate menstrual hygiene facilities and products []. The challenge is even greater in urban slums where poverty, poor sanitation, limited water supply, and deep-rooted cultural taboos hinder proper menstrual hygiene practices []. In Nepal, although national efforts have been made to address adolescent health, menstrual health is still not fully integrated into major public health agendas and remains under-addressed in policy and programme implementation []. Menstruation remains shrouded in silence and stigma in many low- and middle-income countries, where myths, misconceptions, and social restrictions continue to shape women's and girls’ experiences over time []. Women and girls residing in urban slum areas, such as those in Budanilakantha Municipality in Kathmandu, often face compounded vulnerabilities due to their socio-economic conditions, inadequate sanitation infrastructure, and lack of access to health education. These factors collectively impact their ability to manage menstruation safely and with dignity []. Various studies have identified socio-demographic characteristics including age, education, religion, maternal literacy, and income as significant determinants of menstrual hygiene practices [–].