Abstract
The efficacy of n-3 fatty acids supplementation on the prevention of pregnancy-induced hypertension or preeclampsia remains unclear. The aim of study was to examine the effect of supplementation with EPA, and/or DHA, and/or ALA during pregnancy on the pregnancy-induced hypertension or preeclampsia. A systematic search was performed on Scopus, PubMed, Web of Science (WoS), Cochrane Library, and Google scholar, which covered the period between 1991 and 2018. The clinical trials with any control groups (i.e. placebo or other supplementation) were selected. The whole process of meta-analysis and data analysis was done using Comprehensive Meta-Analysis (Version 2.0, Biostat). The searched keywords were: “Fatty Acids, Omega-3”, “n-3 Polyunsaturated Fatty Acid” “Eicosapentaenoic Acid”, “Docosahexaenoic Acids”, “n-3 Polyunsaturated Fatty Acid”, “n-3 PUFAs”, “alpha-Linolenic Acid”, “fish oil”, “Nuts”, “nutrient”, or their synonyms “pregnancy induced hypertension” and preeclampsia. In addition, some key journals, according to Scopus report and the references of the original and review articles, were manually searched for possible related studies. The meta-analysis of the 14 comparisons demonstrated that n-3 fatty acids supplementation played a protective role against the risk of preeclampsia (RR, 0.82; 95% CI, 0.70-0.97; p = 0.024; I2 = 19.0%). The analysis of the 10 comparisons revealed that n-3 fatty acid supplements for pregnant women did not mitigate the risk of pregnancy-induced hypertension (RR, 0.98; 95% CI, 0.90-1.07; p = 0.652; I2 = 0%). The n-3 fatty acid supplements are an effective strategy to prevent the incidence of preeclampsia in women with low-risk pregnancies.
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Key Points
Pregnancy induced-hypertension defined as systolic blood pressure more than or equal to 140 mm of mercury (mmHg) and diastolic blood pressure more than or equal to 90 mmHg during pregnancy. Preeclampsia also refers to a multisystem disease, unique to human pregnancy, which is usually characterized by elevated blood pressure and proteinuria. In this study, several systematic review and meta-analyses were reviewed to evaluate the potential effectiveness of n-3 fatty acid supplements on such maternal health outcomes as pregnancy-induced hypertension and preeclampsia. Although the effectiveness of n-3 fatty acid supplements on the outcomes of pregnancy has been extensively studied, there are a lack of meta-analyses about the effect of n-3 fatty acid supplementation on pregnancy-induced hypertension and preeclampsia. The focus of this review is on the effect of n-3 fatty acid supplements on the preeclampsia or induced-hypertension during pregnancy, whereas preeclampsia and the pregnancy-induced hypertension was one of the subgroups in other studies. In the present meta-analysis, having pooled the results of all clinical trials, it was found that the n-3 fatty acids supplementation during pregnancy did not mitigate the incidence of pregnancy-induced hypertension, neither in general nor in sub-groups’ analyses. In addition, the results of the reviewed studies on the prevention of preeclampsia can substantiate and support the protective role of the n-3 fatty acids supplementation against the risk of preeclampsia. The subgroups analyses also indicated that the results were consistent for women with low-risk pregnancies, for women with intervention starting from the second half of pregnancy, and also for those with EPA and DHA consumption; however, no evidence was found for women with high-risk pregnancies, women with a first half pregnancy intervention, and also those with DHA consumption only. In conclusion, the results of this meta-analysis indicated that the n-3 fatty acids supplementation was an effective strategy to prevent the incidence of preeclampsia in women with low-risk pregnancies.