Burden, risk factors and outcomes of hyperemesis gravidarum in low-income and middle-income countries (LMICs): systematic review and meta-analysis protocol

Introduction Hyperemesis gravidarum (HG) is a pregnancy condition characterised by excessive nausea and vomiting resulting in dehydration, weight loss and serious adverse pregnancy outcomes including termination of pregnancies. Even though evidence in low-income and middle-income countries (LMICs) is limited, the prevalence of HG in pregnancy ranges from 0.3% to 10.8%. With this systematic review and meta-analysis, we aim to determine the prevalence/burden, risk factors, and maternal and perinatal outcomes of HG in LMICs. Methods PubMed, CINAHL, EMBASE, EBSCO, Ovid maternity and infant care databases, Cochrane Database of Systematic Reviews, Web of Science and SCOPUS databases will be searched. Reference lists of selected articles will be assessed in order to identify other potential studies of interest. Observational studies and (non) randomised controlled trials conducted from January 2000 to September 2018 in LMIC will be included. A weighted inverse-variance meta-analysis using fixed-effects and random-effects model will be done to generate a pooled estimate. Funnel plot and Egger's regression statistical test will be applied to check publication bias. Heterogeneity among studies will be checked using T-2 to determine dispersion. Moreover, meta-regression analysis will be performed to investigate the source of heterogeneity. STATA V. 14 will be used to analyse the data. Ethics and dissemination Formal ethical approval and patient consent are not required; as primary data collection will not be employed. The result will be published in a peer-reviewed scientific journal and will be presented at scientific conferences and public press.