Systematic review of short birth interval

There are documented associations between short birth interval and adverse maternal and child health outcomes, including infant and potentially maternal mortality.  Although a number of studies have examined factors related to short birth interval, to our knowledge, no previous systematic review has systematized this evidence. Our review aimed to identify the factors associated with short birth interval in low- and middle-income countries.

The review searched PubMed, Embase, LILACS, and Popline databases for empirical studies on the topic. We included documents in English, Spanish, French, Italian, and Portuguese, without date restriction. Two independent reviewers screened the articles and extracted the data. The definition of potentially causal factors and outcomes was heterogeneous, and we performed only a narrative synthesis of the findings.

43 of an initial 2802 documents met inclusion criteria, 14 of them published after 2010, and 30 of them observational studies. 21 studies were from Africa, 18 from Asia, and four from Latin America. 32 publications reported quantitative studies (16 studies reported odds ratio or relative risk, 16 studies reported hazard ratio), 10 qualitative studies, and one a mixed-methods study. The factors most commonly studied included age and education of the mother and use of contraception. For most factors, studies reported both positive and negative associations with short birth interval. Shorter breastfeeding, female sex of the previous child, and a negative outcome of the previous pregnancy were consistently associated with short birth interval. A paper describing the systematic review has been submitted for publication.