Aguilar-Cordero MJ, Lasserrot-Cuadrado A, Mur-Villar N, León-Ríos XA, Rivero-Blanco T, Pérez-Castillo IM. Vitamin D, preeclampsia and prematurity: A systematic review and meta-analysis of observational and interventional studies.
Midwifery 2020;
87:102707. [PMID:
32438283 DOI:
10.1016/j.midw.2020.102707]
[Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 01/10/2023]
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.
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