Relationship between vaginal and gut microbiome and pregnancy outcomes in eastern Ethiopia: a protocol for a longitudinal maternal-infant cohort study (the EthiOMICS study)

Introduction: Although evidence exists on the impact of microbiota on pregnancy outcomes in many high-resource settings, there is a lack of research in many low-resource settings like Ethiopia. This study aims to fill this gap by studying the gut and vaginal microbiota changes throughout pregnancy and assess how these changes relate to pregnancy outcomes among a cohort of pregnant women in eastern Ethiopia.

Methods and analysis: Vaginal and stool samples will be collected using DNA/RNA Shield Collection kits three times starting at 12-22 weeks, 28-36 weeks and at birth (within 7 days). Postnatally, newborns' skin swabs (at birth) and rectal swabs will be obtained until 2 years of age. Moreover, breast milk samples at birth and 6 months and environmental samples (water, indoor air and soil) will be collected at enrolment, birth, 6, 12 and 24 months post partum. DNA will be extracted using Roche kits. Metagenomic sequencing will be performed to identify metataxonomic profiling and assess variations in microbial profiles, and α and β diversity of the microbiota. Information on socioeconomic, behavioural, household and biological factors will be collected at enrolment. The collected data will be coded, entered into EpiData 3.1 and analysed using Stata 17.

Ethics and dissemination: The Institutional Health Research Ethics Review Committee (Ref No. IHRERC/033/2022) of Haramaya University, Ethiopia has approved this study ethically. Written informed consent regarding the study and sample storage for biobanking will be obtained from all participants. Results will be published in international peer-reviewed journals, and summaries will be provided to the study funders. Clinical study data will be submitted to Data Compass (https://datacompass.lshtm.ac.uk/), and molecular profiles of the microbiome and whole-genome sequences will be submitted to the European Nucleotide Archive (https://www. ebi.ac.uk/ena). Requests for data should be directed to [email protected]. The decision to share data will be made by the study steering committee under the College of Health and Medical Sciences, Haramaya University, Ethiopia.