Meta‐analysis of the effect of the maternal vitamin D level on the risk of spontaneous pregnancy loss

Zhang, Heng; Huang, Zhaohui; Xiao, Limin; Jiang, Xiaohong; Chen, Daozhen; Wei, Yarong

doi:10.1002/ijgo.12209

Cited by 30 publications

(21 citation statements)

References 35 publications

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“…After title and abstract screening, 42 records were identified. Three SRs did not report on any of our predefined outcomes and were excluded,20–22 and one SR was represented by both a Cochrane and journal publication reporting the same data 23 24. Based on the AMSTAR assessment, 25 reviews were categorised as low or medium quality and were not included in the data extraction and outcome assessment.…”

Section: Resultsmentioning

confidence: 99%

Vitamin D supplementation to improve pregnancy and perinatal outcomes: an overview of 42 systematic reviews

et al. 2020

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ObjectiveTo review the evidence to assess effectiveness of vitamin D supplementation during pregnancy and associations of serum vitamin D levels with perinatal outcomes.DesignOverview of systematic reviews (SRs).Data sourcesSearches conducted in January 2019: Ovid Medline (1946–), Cochrane Library databases.Eligibility criteria for selecting studiesTwo reviewers independently screened titles and abstracts, and full texts using predefined inclusion criteria: SRs evaluating vitamin D supplementation in pregnant women and/or examining the association between serum vitamin D levels reporting at least one predefined perinatal outcome. Only SRs with high AMSTAR scores were analysed.Data extraction and synthesisData were extracted independently by one reviewer and checked by a second. Results were assessed for quality independently by two reviewers using GRADE criteria.ResultsThirteen SRs were included, synthesising evidence from 204 unique primary studies. SRs of randomised controlled trials (RCTs) with the highest level of evidence showed no significant benefit from vitamin D in terms of preterm birth (RR 1.00 (95% CI 0.77, 1.30); high quality), pre-eclampsia (RR 0.91 (0.45, 1.86); low quality), gestational diabetes (RR 0.65 (0.39, 1.08); very low quality), stillbirth (RR 0.75 (0.50, 1.12); high quality), low birth weight (RR 0.74 (0.47, 1.16); low quality), caesarean section (RR 1.02 (0.93, 1.12); high quality). A significant difference was found for small for gestational age (RR 0.72 (0.52, 0.99); low quality). SRs of observational studies showed associations between vitamin D levels and preterm birth (RR 1.19 (1.08, 1.31); moderate quality), pre-eclampsia (RR 1.57 (1.21, 2.03) for 25-hydroxy vitamin D (25 (OH)D)<50 nmol/L subgroup; low quality), gestational diabetes (RR 1.12 (1.02, 1.22) for 25 (OH)D<50 nmol/L and RR 1.09 (1.03, 1.15)<75 nmol/L; moderate quality) and small for gestational age (RR 1.35 (1.18, 1.54)<50 nmol/L; low quality). SRs showed mixed results for associations between vitamin D and low birth weight (very low quality) and caesarean section (very low quality).ConclusionThere is some evidence from SRs of observational studies for associations between vitamin D serum levels and some outcomes; however SRs examining effectiveness from RCTs showed no effect of vitamin D supplementation in pregnancy with the exception of one predefined outcome, which had low quality evidence. Credibility of the evidence in this field is compromised by study limitations (in particular, the possibility of confounding among observational studies), inconsistency, imprecision and potential for reporting and publication biases.

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Section: Resultsmentioning

confidence: 99%

Vitamin D supplementation to improve pregnancy and perinatal outcomes: an overview of 42 systematic reviews

et al. 2020

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“…Thus, severe maternal VDD may be a modifiable risk factor in early embryonic development. 60 Hou et al 61 found that having 1 or more histories of failed clinical pregnancy in the first trimester was significantly associated with VDD, 97% of women with 1 or more SA had serum 25(OH)D concentrations below 30 ng/mL.…”

Section: Introductionmentioning

confidence: 99%

“…Several studies were published about the relationship between VDD and sporadic SA. Zhang et al (2017) in a systematic review and meta-analysis, which included 5 cohort studies, [55][56][57][58][59] concluded that an extremely low 25(OH)D level (<20 ng/mL) was significantly associated with an increased risk of SA in the first trimester. Thus, severe maternal VDD may be a modifiable risk factor in early embryonic development.…”

Section: Introductionmentioning

confidence: 99%

Recurrent pregnancy loss and vitamin D: A review of the literature

Gonçalves

Braga

et al. 2018

American J Rep Immunol

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Recurrent pregnancy loss (RPL) affects approximately 1%-2% of reproductive women. Auto- and cellular immune responses seem to be associated with RPL. Vitamin D (VD) has been shown to play a role in the modulation of the immune system. Effects of VD deficiency (VDD) in pregnancy have been associated with preeclampsia, gestational diabetes, fetal growth restriction, preterm labor, and sporadic spontaneous abortion (SA). We systematically reviewed articles that studied women with 2 or more SA and its association with VD. Eleven studies were included. Studies reported a high prevalence of VD insufficiency (VDI) or VDD in women with RPL and suggested that this could be associated with immunological dysregulation and consequently with RPL. Immunological benefits were reported in the peripheral blood of women with RPL after VD exposure. Thus, it is possible to speculate a beneficial role for VD supplementation in RPL. It seems that there are not differences in the vitamin D receptor (VDR) and CYP27B1 expression in endometrium of women with RPL but, in villous and decidual tissues, RPL women seem to have a decreased expression of VDR and, perhaps, a decreased expression of CYP27B1. Further randomized controlled studies are required to investigate the association between VDD or VDI and RPL.

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“…They did, however, find an increased risk of miscarriage at much lower levels of vitamin D, specifically <20 ng/mL, (RR 2.24, 1.15-4.37). They concluded that severe vitamin D deficiency might be detrimental to early embryonic development and increase the risk of first trimester pregnancy losses (Zhang et al, 2017).…”

Section: Reviewmentioning

confidence: 99%

Vitamin D and Infertility: The Evidence

Hornstein

2019

FandR

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Vitamin D is a lipid soluble vitamin synthesized by the skin upon exposure to UV light. Approximately 10–20% of vitamin D comes from dietary sources and 25OH-D is its circulating form. Vitamin D receptors are found in reproductive tissues including ovary, uterus, and endometrium permitting investigators to hypothesize a role for vitamin D in reproduction. Indeed, a number of animal studies provide evidence of vitamin D’s importance in fertility. Studies in humans, however, generally have not supported an effect of vitamin D on fertility outcomes. Several retrospective cohort studies did not demonstrate an association between vitamin D levels and pregnancy. Similarly, one study did not find correlation between anovulatory infertility and vitamin D intake. Very low levels of vitamin D, however, were associated with miscarriage in another study. A large meta-analysis of 11 studies and 2700 women did show an improvement in IVF success rates in those with higher levels of vitamin D. Finally, two small studies on vitamin D supplementation and pregnancy did not show a benefit of increasing vitamin D intake. In conclusion, the literature at best shows a minimal impact of vitamin D on infertility and IVF outcomes.

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Meta‐analysis of the effect of the maternal vitamin D level on the risk of spontaneous pregnancy loss

Abstract: Severe Vitamin D deficiency could be detrimental to early embryonic development and increase the risk of early SPL.

Cited by 30 publications

References 35 publications

Vitamin D supplementation to improve pregnancy and perinatal outcomes: an overview of 42 systematic reviews

Vitamin D supplementation to improve pregnancy and perinatal outcomes: an overview of 42 systematic reviews

Recurrent pregnancy loss and vitamin D: A review of the literature

Vitamin D and Infertility: The Evidence

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