Feasibility and Validity of Mobile Phone‐Based Proxy Full Pregnancy History ( mPFPH ) for Estimating Perinatal Mortality in Rural Northwest Bangladesh

OBJECTIVES: Robust estimates of perinatal mortality are essential for improving perinatal survival in low- and middle-income countries. Mobile phone surveys may offer a scalable alternative to in-person surveys for such estimates. This study assessed the feasibility and validity of mobile phone-based Proxy Full Pregnancy History (mPFPH) interviews in rural Bangladesh, comparing proxy-reported and self-reported full pregnancy histories collected via mobile phones. METHODS: Between June and November 2022, women who had experienced at least one adverse pregnancy outcome (index women) and their nominated closest confidants participated in mobile phone interviews. Self-reports served as the reference standard. We examined selection biases associated with mobile phone access and evaluated concordance between self- and proxy-reports for perinatal outcomes. RESULTS: A total of 1838 index women and 1328 confidants were enrolled. Non-response rates ranged from 2.1% to 26.5%, with non-respondents more likely to be younger, multiparous, and from smaller households. Average interview durations ranged from 7.5 to 25 min. Compared with self-reports, proxy reports by index women and closest confidants underreported neonatal deaths by 9.9% (95% CI: 7.0%-12.8%) and 23.1% (95%-CI: 15.0%-31.2%), perinatal deaths by 13.6% (95%-CI: 11.2%-16.0%) and 21.3% (95%-CI: 15.1%-27.6%), early neonatal deaths by 11.6% (95%-CI: 8.2%-14.9%) and 20.5% (95%-CI: 11.6%-29.5%), stillbirths by 14.6% (95%-CI: 11.2%-18.0%) and 22.4% (95%-CI: 13.5%-31.2%), and other pregnancy losses by 30.8% (95%-CI: 27.1%-34.4%) and 46.9% (95%-CI: 41.4%-52.5%). The proxy-to-self rate ratios for index women were 0.91 (95%-CI: 0.79-1.04) for neonatal mortality, 0.89 (95% CI: 0.80-0.98) for perinatal mortality, 0.89 (95%-CI: 0.76-1.04) for early neonatal mortality, 0.88 (95% CI: 0.76-1.01) for stillbirths, and 0.74 (95% CI: 0.65-0.83) for other pregnancy losses. CONCLUSION: The mPFPH method demonstrated feasibility through high response and completion rates, efficient call durations, and strong two-way validation. However, proxy reports underestimated perinatal mortality relative to self-reports. Further validation across diverse settings is needed before large-scale implementation.