Cohort Profile: PRECISE-DYAD: a prospective cohort study linking maternal and infant health trajectories in sub-Saharan Africa

Purpose: The PRECISE-DYAD study is a prospective observational cohort, designed to investigate health outcomes among mother-child pairs (dyads), over the first three years of life in two contexts from sub-Saharan Africa. The primary objective of the study was to explore the effects of selected placenta-related complications, such as pregnancy hypertension, fetal growth restriction, and preterm birth, on 1) child health and development, and 2) women's health and well-being, including outcomes after stillbirth Participants: The PRECISE-DYAD study enrolled women (and their children) originally recruited into the PRECISE regnancy cohort study in The Gambia and Kenya between July 2021 and April 2024. Participants were seen at 6 weeks to 6 months, 12 months, 24 months, and 36 months post-partum. Clinical and health data, including anthropometry and diet were collected for both mothers and children. Mother assessment included a cardiology assessment and collection of data about symptoms of COVID-19 infection. In a subset of participants, mothers were asked about their mental health, their health care costs during and after pregnancy, and experiences of care during labour and childbirth / delivery. Additonally, a personal environmental exposure assessement was performed for a subset of the cohort, by collecting air and water quality data alongside geographical, demographic, and behavioural factors. Child development was assessed using neurodevelopmental assessments, home environment evaluation, and quality of life measures. Biological samples were collected from mothers and children, processed promptly and biobanked locally. Sample data were entered into an OpenSpecimen database and linked to each individual, as well as to their corresponding social determinants and clinical data. Findings to date: A total of 2,980 women and 2,909 children completed at least one PRECISE-DYAD study visit. The biorepository contains 108,897 biological samples from mothers and children. Baseline descriptive analysis of the cohort are reported here. Future plans: Analysis of data and samples will include biomarker studies, social determinants of health, and epidemiological investigations. These analyses will explore how placenta-related complications and environmental exposures, such as nutrition and air quality, interact to shape maternal health, mental well-being, subsequent pregnancies, and mother-child interaction, as well as child growth and neurodevelopment through early childhood. Additional work will examine the biological pathways linking these exposures to outcomes and the impacts of caring for children with moderate-to-severe disabilities on maternal well-being. Findings will be disseminated through scientific publications, conference presentations, engagement with local stakeholders, and continued community outreach.