Vitamin D, preeclampsia and prematurity: A systematic review and meta-analysis of observational and interventional studies. (August 2020)

• Record Type: Journal Article
• Authors: Aguilar-Cordero, M.J.; Lasserrot-Cuadrado, A.; Mur-Villar, N.; León-Ríos, X.A.; Rivero-Blanco, T.; Pérez-Castillo, I.M.
• Is Part Of: Midwifery. Volume 87(2020)
• Publication Date: 2020-08
• Subjects: Vitamin D -- Preeclampsia -- Preterm birth -- Systematic review -- Meta-analysis; BMI body mass index -- CLIA chemiluminescent immunoassay -- ECLIA electrochemiluminiscent immunoassay -- ELISA enzyme-linked immunosorbent assay -- HPLC high performance liquid chromatography -- LC/MS liquid chromatography–mass spectrometry -- n number of participants -- RIA radio immunoassay -- VDR vitamin D receptor -- wk. weeks of gestation; Midwifery -- Periodicals; Midwifery -- Periodicals; Sages-femmes -- Périodiques; Midwifery; Periodicals; Electronic journals; 618.2005
• DOI: 10.1016/j.midw.2020.102707
• Languages: English
• ISSNs: 0266-6138

Abstract

Highlights: Preeclampsia and prematurity rates are higher among vitamin D deficient women. Studies varied with regards to covariates, design, location and outcome definition. Fixed and random effect meta-analyses evidenced discordant results. The significance of associations must be clarified through well-designed clinical trials. Abstract: Background: Vitamin D has important functions outside of bone metabolism. Deficiency has been associated with several adverse outcomes during pregnancy such as preeclampsia and prematurity. There is an increasing body of literature on this topic with studies performed to date having produced contradictory results. Objective: To synthesize the literature about vitamin D deficiency and its association with preeclampsia and prematurity in order to determine if maternal vitamin D insufficiency and/or deficiency during pregnancy is associated with the prevalence of preeclampsia and prematurity. Design: A systematic review and meta-analysis of observational and interventional studies. Methods: Two independent researchers reviewed the included studies according to PRISMA reporting guidelines. A protocol for this review was registered in PROSPERO with the registration number: "CRD42019136318". Three electronic databases (PubMed, ScienceDirect and Web of Science); were searched in order to identify eligible studies. Observational and interventional studies were selected which had been published in the last 6 years, and analysed the association between maternal vitamin D concentrations during pregnancy and the development of preeclampsia and/or preterm birth. Data were extracted and presented in tables and figures. Fixed and random-effects meta-analyses were performed on the studies which provided enough sample data to calculate odds ratios. Results from both statistical methods were compared. Meta-analysis cut-off points for vitamin D insufficiency and deficiency were defined as <75nmol/L and <50nmol/L, respectively. Results: Fifty-five studies met the inclusion criteria. Fixed-effects meta-analysis of the interventional studies indicated that vitamin D supplementation acts as a prevention factor for preeclampsia and prematurity. Fixed-effects meta-analysis of observational studies concluded that vitamin D insufficiency and deficiency are associated with a higher risk of developing preeclampsia. However, prematurity and vitamin D were only associated when maternal vitamin D concentrations was <75 nmol/L. Random-effects meta-analysis found no significant association between vitamin D, preeclampsia and prematurity in either observational or interventional studies. Conclusion: Higher vitamin D concentrations during pregnancy could be associated with a decreased risk of preeclampsia and prematurity but statistical significance of associations depends on the study design used. Well-designed clinical trials with vitamin D supplementation are needed in order to better define associations.