Interpregnancy interval and risk of perinatal death: a systematic review and meta-analysis.

BACKGROUND: Interpregnancy interval (IPI) <6 months is a potentially modifiable risk factor for adverse perinatal health outcomes. OBJECTIVE: This systematic review evaluated the international literature on the risk of perinatal death associated with IPI. SEARCH STRATEGY: Two independent reviewers screened titles and abstracts identified in MEDLINE, EMBASE, and Scopus from inception to 4 April 2019 (Prospero Registration# CRD42018092792). SELECTION CRITERIA: Studies were included if they provided a description of IPI measurement and perinatal death, including stillbirth and neonatal death. DATA COLLECTION AND ANALYSIS: A narrative review was performed for all included studies. Random-effects meta-analysis was used to compare unadjusted odds of perinatal death associated with IPI <6 months and IPI ≥6 months. Analyses were performed by outcome of the preceding pregnancy and study location. MAIN RESULTS: Of the 624 unique articles identified, 26 met inclusion criteria. The pooled unadjusted odds ratio of perinatal death for IPI <6 months was 1.34 (95% CI 1.17, 1.53) following a previous live birth, 0.85 (95% CI 0.73, 0.99) following a previous miscarriage, and 1.07 (95% CI 0.84, 1.36) following a previous stillbirth compared to IPI ≥6 months. However, few high-income country (HIC) studies reported an association after adjustment. Fewer studies evaluated the impact of long IPI on perinatal death and what evidence was available showed mixed results. CONCLUSIONS: Results suggest a possible association between short IPI and risk of perinatal death following a live birth, particularly in LMICs. FUNDING: This work was supported by funding from the National Health and Medical Research Council (GNT1099655).