Association between intrauterine device use and preeclampsia risk: a meta-analysis of observational studies

Background: Preeclampsia, whose causes remain unknown, is a multifaceted syndrome suffered by pregnant women world-wide. Objectives: This study is to quantitatively analyze the association between exposure to intrauterine devices (IUDs) and risks of developing preeclampsia during pregnancy. Search strategy: Literature search was performed on Pubmed, Medline, EMBASE and COHRANE Library. Both mesh terms and free terms were used. Reference lists were also reviewed. Section criteria: Primary studies that described preeclampsia as one of the outcomes of interest between women exposed (IUD was used during or before pregnancy) and unexposed (no IUD use) to IUDs were included. Data collection and analysis: The summary risk ratios (RRs) were estimated using a fixed effect model. Risk of bias was assessed with the Newcastle-Ottawa Scale (NOS) System. Main results: Two retrospective cohort studies (n = 153780) and one case-control study (n = 13900) were included. The summary RR for previous use of IUDs (in situ or early removal) vs no use of IUDs was 0.74 (95% CI, 0.61-0.90). No statistically significant difference was found between pregnancy with an IUD in situ and IUD early removal (RR = 0.74, 95% CI, 0.37-1.47). Conclusions: Any use (either before or during pregnancy) of IUDs may contribute to the reduced risk of preeclampsia.