Inter-pregnancy interval and risk of recurrent pre-eclampsia: systematic review and meta-analysis

Abstract

Background: Women with a history of pre-eclampsia have a higher risk of developing pre-eclampsia in subsequentpregnancies. However, the role of the inter-pregnancy interval on this association is unclear.Objective: To explore the effect of inter-pregnancy interval on the risk of recurrent pre-eclampsia or eclampia.Search strategy: MEDLINE, EMBASE and LILACS were searched (inception to July 2015).Selection criteria: Cohort studies assessing the risk of recurrent pre-eclampsia in the immediate subsequentpregnancy according to different birth intervals.Data collection and analysis: Two reviewers independently performed screening, data extraction, methodologicaland quality assessment.Meta-analysis of adjusted odds ratios (aOR) with 95 % confidence intervals (CI) was used to measure the associationbetween various interval lengths and recurrent pre-eclampsia or eclampsia.Main results: We identified 1769 articles and finally included four studies with a total of 77,561 women. The meta-analysisof two studies showed that compared to inter-pregnancy intervals of 2?4 years, the aOR for recurrent pre-eclampsia was 1.01 [95 % CI 0.95 to 1.07, I2 0 %] with intervals of less than 2 years and 1.10 [95 % CI 1.02 to 1.19, I2 0 %] with intervals longerthan 4 years.Conclusion: Compared to inter-pregnancy intervals of 2 to 4 years, shorter intervals are not associated with an increasedrisk of recurrent pre-eclampsia but longer intervals appear to increase the risk. The results of this review should beinterpreted with caution as included studies are observational and thus subject to possible confounding factors.Keywords: Recurrence, Pre-eclampsia, Eclampsia, Inter-pregnancy interval, Birth interval, Meta-analysis, Systematic review,Birth spacing, Hypertensive disorders of pregnancy