Objectives: The purpose of this study is to investigate whether calcium supplement with or without other drugs could reduce the risk of preeclampsia and gestational hypertension based on existed evidence, and to clarify whether there is discrepant effect among different population and using different dose. Methods: PubMed, Cochrane library, and EMBASE database were searched. Two authors independently screened all records and extracted data. The meta-analysis was performed to calculate risk ratios and 95% CIs using random-effects models. Results: 27 studies, with 28 492 pregnant women were included. The results showed calcium supplement was associated with lower incidence of preeclampsia (RR 0.51, 95% CI: 0.40 to 0.64) and gestational hypertension (RR 0.70, 95% CI: 0.60 to 0.82). Sub-analyses revealed high-dose (1.2-2 g/day), moderate-dose (0.6-1.2 g/day), and low-dose (<0.6 g/day) of calcium supplement could reduce the risk of preeclampsia. For gestational hypertension, only high dose and moderate dose groups were associated with reducing the risk of gestational hypertension. However, we could draw a conclusion which does group was the most protective, as we were unable to directly compare the effects of different doses. Conclusions: This study indicated calcium supplementation might decrease the risk of preeclampsia and gestational hypertension. And results of subgroups analyses enhanced our confidence to the protective effect of calcium supplementation. However, further studies with direct comparison of different dose of calcium supplementation are needed to explore the ideal dose of calcium supplementation to prevent preeclampsia and gestational hypertension.

Authors' objectives: The objective of this health technology assessment is to address questions regarding: 1) safety, effectiveness and health services utilisation associated with the use of Elecsys immunoassay sFlt-1/PlGF ratio, Triage PlGF-test, DELFIA Xpress PlGF 1-2-3 test, BRAHMS sFlt-1 Kryptor/BRAHMS PlGF-pluss Kryptor PE ratio or other blood-based tests for predicting suspected preeclampsia in 2nd and 3rd trimester; 2) predictive accuracy of these tests; 3) cost-effectiveness and budgetary consequences of implementation; and evaluate the intervention against the priority setting criteria applicable in Norway (benefit, resource use and severity).