Measurement, prevalence, causes, and health outcomes of co-existing multiple high-risk factors in pregnancy: a systematic review and meta-analysis

Abstract Background The co-occurrence of multiple high-risk factors during pregnancy (MHFP) is becoming increasingly common in transitioning populations, and may cause higher risk of adverse pregnancy outcomes. We performed a systematic review to better understand and summarize current evidence on MHFP. Methods Of 10,502 studies found, 46 original research met the inclusion criteria. Existing evidence on the measurement and definition, prevalence, causes, and health outcomes of MHFP were extracted and synthesized. The prevalence of MHFP was pooled through meta-analysis with random effects model. The linear regression model was used to estimate the trends of MHFP prevalence stratified by income levels of countries. Results Among 46 included studies, 76% were from high-income countries (HICs). The definition and types of high-risk factors in pregnancy are complex, multidimensional, and subjective. Four dimensions of MHFP were identified, including physical conditions, mental conditions, social-behavioural problems, and pregnancy history. Co-existing multiple physical conditions were the most common MHFP patterns, and anxiety-depression was the most studied MHFP pair. The overall pooled prevalence of MHFP was 16% according to included studies, with similar prevalence in HICs and low- and middle-income countries (LMICs). However, publications from LMICs were limited. Only three studies investigated the potential causes of MHFP. MHFP would affect women and their children’s health at multiple life stages. Conclusion The definition, measurement, potential clustered patterns, causes, and health outcomes of MHFP are poorly reported and highly variable. Relevant studies, including prospective cohort studies and randomized control trials, are warranted to provide more evidence on MHFP, so as better design and implement prevention and intervention programmes.