Pregnancy with multiple high-risk factors: a systematic review and meta-analysis

A wide spectrum of high-risk factors in pregnancy can lead to adverse pregnancy outcomes or short- or long-term health effects. Despite this, there has been no synthesis of findings on the measurement, potential causes, and health outcomes of multiple high-risk factors in pregnancy (MHFP). We aimed to address this gap by summarising the existing research on this topic.

We retrieved studies published up to 3 June 2024 through systematic database searches and used a narrative synthesis approach to summarise the measurement, patterns, causes, and outcomes of MHFP. We also estimated the pooled MHFP prevalence through meta-analysis with a random effects model and performed subgroup analyses and meta-regression to examine potential sources of between-study heterogeneity.

We included 83 observational studies published between 2010 and 2024, of which 72% were from high-income countries. These studied factors can be grouped into four categories: physical conditions, mental conditions, sociobehavioural problems, and pregnancy history. We identified 16 MHFP patterns, among which co-existing multiple physical conditions were the most common pattern. The overall pooled prevalence of MHFP was 12% (95% confidence interval (CI) = 12-13), with an increasing trend and relatively higher levels in low- and middle-income countries (LMICs). We observed heterogeneity in the measurement of MHFP across the studies, possibly due to the number of risk factors in the definition of MHFP. About 78% of included studies investigated MHFP-associated health outcomes for women and offspring, with only two studies examining long-term maternal or offspring outcomes later in life.

Research into MHFP has been emerging over the past decade, but is far from complete. The burden of MHFP is increasing worldwide, particularly LMICs. Maternal healthcare systems must shift to a multidisciplinary and integrated framework so as to better design and implement prevention and intervention programmes and sustain the healthy development of the next generation.

PROSPERO: CRD42022358889.