Exploring Behavioral Interventions to Improve Adherence to Multiple Micronutrient Supplements Among Pregnant Women in Cambodia

This mixed-methods study will explore how three behavioral interventions can support pregnant women in Cambodia to take a daily multiple micronutrient supplement (MMS) as recommended throughout pregnancy and how acceptable and useful these interventions are in their daily lives. The study is being conducted in four provinces in Cambodia (Kampong Chhnang, Ratanakiri, Takeo, and Kampot) and enrolls healthy pregnant women in early pregnancy who attend antenatal care (ANC) at selected health centers. Its findings will help inform Cambodia's planned transition from iron-folic acid to MMS by identifying feasible, family- and community-appropriate strategies to promote high adherence.

The study focuses on three behavioral interventions: (1) a family support session, (2) a tracking calendar, and (3) short educational videos delivered via mobile phone. All enrolled participants are asked to take MMS daily and are sequentially exposed to each of the three interventions, with time between them to try out and reflect on each one. After using each intervention for approximately three weeks, participants join a focus group discussion to describe their experiences, including what helped or hindered their daily MMS intake and what they liked or disliked about the intervention. At each discussion, study staff also count remaining MMS tablets to calculate adherence over that period.

The family support intervention is designed to strengthen the role of close relatives-especially husbands and other key family members-in supporting women's daily MMS intake and broader healthy pregnancy practices. Each pregnant woman is invited to bring two family members of her choice to a one-hour, group-based session at the health center, led by trained midwives and research staff. The session covers essential ANC topics, the benefits and importance of daily MMS, and specific, practical ways family members can help, such as giving reminders, reducing the woman's household workload, or helping her keep MMS in a visible place. Family members can ask questions, discuss challenges, and receive a take-home handout summarizing key messages and suggested supportive actions. Women then return home and experience family support in their everyday context for about three weeks before attending a focus group discussion to describe what kind of support they actually received and how it affected their MMS-taking routine.

The tracking calendar intervention provides a visual tool that women can use at home to monitor and encourage their daily MMS intake and healthy pregnancy behaviors. After completing the family support phase, each participant receives a culturally tailored calendar designed with simple Khmer text and clear illustrations that are suitable for users with varying literacy levels. The calendar includes a daily space to mark when MMS has been taken, reminders for scheduled ANC visits, and icons that promote positive pregnancy practices such as eating a balanced diet and resting, as well as icons indicating behaviors to avoid, such as alcohol use and heavy lifting. Research staff give a short orientation on how to use the calendar, showing women how to mark each day and interpret the symbols. Women then use the calendar at home for about three weeks. A follow-up focus group discussion is conducted to learn how they used the calendar, whether it helped them remember to take MMS, what they found easy or difficult, and what improvements they suggest.

The video intervention uses digital communication to reach women in their homes and reinforce key MMS and pregnancy messages. Over a three-week period, participants receive one short motivational video per week via Telegram, a commonly used messaging application in Cambodia. The videos are in Khmer and feature midwives providing counseling and encouragement on daily MMS adherence, addressing common reasons for missed doses (such as forgetfulness or side effects), and emphasizing the importance of family support. The scripts are developed by the research team with input from maternal health experts, and the videos are pretested with pregnant women not enrolled in the main study to ensure that the messages are clear, relevant, and engaging. At the end of the three-week video period, participants take part in another focus group discussion to share how they watched and understood the videos, what they found most useful or challenging, and whether the videos influenced their MMS-taking habits.