Hypertension in pregnancy as a risk factor for placenta accreta spectrum: a systematic review incorporating a network meta-analysis

Background A meta-analysis was performed to evaluate the potential effects of hypertension in pregnancy on the placenta accreta spectrum. Methods A systematic literature search in OVID, Embase, Cochrane Library, PubMed, and Google Scholar up to May 2021 was done, and six studies were found including 126,224 pregnant women; 7164 of them had hypertension in pregnancy and 816 had placenta accreta spectrum. They were reporting relationships between the potential effects of hypertension in pregnancy on the placenta accreta spectrum. The odds ratio (OR) with 95% confidence intervals (CIs) was calculated to assess the potential effects of hypertension in pregnancy on the placenta accreta spectrum using the dichotomous with a random- or fixed-effect model. Results Pregnancy-induced hypertension was significantly related to lower prevalence of placenta accreta spectrum (OR 0.56; 95% CI 0.37–0.84, p = 0.005) with no heterogeneity ( I 2 = 0%) compared to control (no hypertension in pregnancy). When looking at the result comparing the prevalence of hypertension in pregnancy in women with placenta accrete compared to control (no placenta accrete), we found that the placenta accreta spectrum was significantly related to lower prevalence of hypertension in pregnancy (OR 0.65; 95% CI 0.43–0.98, p = 0.04) compared to control. Conclusions Hypertension in pregnancy may have a lower prevalence of placenta accrete. Further studies are required to validate these findings.