Determinants of short interpregnancy intervals in high-income countries: a systematic review

Short interpregnancy intervals (IPIs) of <6-18 months are associated with adverse maternal and child outcomes. This study aimed to identify the individual, relationship, community, and societal factors that influence short IPIs in high-income countries. A comprehensive search was undertaken in CINAHL Plus, Ovid/EMBASE, Ovid/MEDLINE, Ovid/PsycINFO, ProQuest, PubMed, Scopus, Web of Science, and Google Scholar for articles published in English from 1st January 1990 to 26th October 2023. Studies were included if they reported an effect estimate of at least one determinant of pregnancy spacing in a high-income country. The quality of the included studies was assessed using the Johanna Briggs Institute Critical Appraisal Tool and Cochrane Risk Assessment Tool. Multi-level factors at the individual, relationship, community, and societal level were systematically identified through the socio-ecological model. This study is registered with PROSPERO (CRD42020176311). Of 2005 unique articles, 220 were identified for full-text review, and 55 met the inclusion criteria representing a total of 27,103,055 women from 13 high-income countries. All the included studies were deemed to be of moderate to high quality. Most of the studies reported determinants of short IPI at the individual level, with non-use of contraception the most common reported factor. Peer influence was a factor at the relationship level, and access to health care and reproductive services were impactful at the community and societal levels, respectively. Future research and efforts should support the development and implementation of policies and practices that support optimum pregnancy spacing from a comprehensive socio-ecological position.