Objectives In many Low- and Middle-Income Countries, perinatal mortality estimates are derived retrospectively from periodically conducted household surveys. Mobile phone surveys offer advantages in terms of cost and ease of implementation. However, their suitability for monitoring perinatal mortality has not been established.

Methods We use data from the Malawi Rapid Mortality Mobile Phone Survey (RaMMPS) to estimate perinatal mortality rates from two versions of the survey instrument: a Full Pregnancy History (FPH) and a shorter Truncated Pregnancy History (TPH). Female respondents of reproductive age were randomly allocated to either of these instruments. The sample was generated through random digit dialling (RDD) with active strata monitoring. Post-stratification weighting was used to correct for sample selection bias, and estimates are reported with bootstrap confidence intervals. We estimated the stillbirth rate as the synthetic cohort probability of a foetal death with 28+ weeks of gestation over all pregnancies reaching the same gestational age. The perinatal and extended perinatal mortality rates were defined as the probabilities of dying between 28 weeks and 7 or 28 days of life, respectively. RaMMPS estimates are compared to the 2015-16 Malawi Demographic and Health Survey, and estimates published by the United Nations Inter-agency Group for Child Mortality Estimation (UN-IGME).

Results TPH and FPH were administered for 2,117 and 2,086 women, respectively. Weighted point estimates of the stillbirth (19.38 deaths per 1,000 pregnancies, 95%-Confidence Interval (CI): 14.03-25.42), perinatal (42.00, 95%-CI: 34.27-50.78), and extended perinatal mortality rates (49.57, 95%-CI: 41.62-59.43) from the FPH instrument are in line with DHS and UN-IGME estimates. In comparison, the stillbirth rate from the TPH instrument is biased upwards. Post-stratification weighting produces a small upwards adjustment in the estimates.

Conclusion MPS are a promising method for collecting perinatal mortality data. The FPH instrument produces more plausible results than the shorter TPH questionnaire where the window of retrospection is restricted.

The authors have declared no competing interest.

This study was made possible with financial support from the Bill and Melinda Gates Foundation (INV-023211). The funder had no role in study design, data collection, data analysis, data interpretation, or writing of the report.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study protocol was reviewed Ethics Committee of the London School of Hygiene and Tropical Medicine (reference: 26393/RR/24486) and the University of Malawi Research Ethics Committee (reference: P.07/21/76). All participants provided oral consent for the survey, including consent for storing anonymized data in a public repository and consent to audio record the interview.

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Malawi RaMMPS data can be requested via email to the corresponding author or rammpslshtm.ac.uk. Code to reproduce the results is available from the GitHub repository maintained by JRP (https://github.com/Romero-Prieto/RaMMPS_Malawi)