Maternal vitamin D status in pregnancy: a critical appraisal of current analytical data on maternal and neonatal outcomes

Abstract

Maternal hypovitaminosis D during pregnancy has been associated with a wide spectrum of adverse maternal and neonatal health outcomes, some manifesting stronger associations than others. Research in this field has entered the "era of systematic data evaluation" via the conducting of a series of meta-analyses in an attempt to synthesize the diverse data from observational and supplementation studies. The aim of this review was to provide a critical appraisal of published observational and interventional (supplementation) meta-analyses on the link between maternal vitamin D status and health consequences to both mothers and neonates. A literature review was performed by two reviewers in the Medline and Embase databases, from inception to March 2014, without any language restriction. Additional articles were identified by a manual search of the references from the key articles retrieved. The results provided evidence that the meta-analyses on the link between maternal vitamin D status and maternal / neonatal health consequences are characterized by a wide heterogeneity of studied populations as well as methodological pitfalls, including the absence of standardized vitamin D assays and evaluation of vital external regulators of vitamin D bio-networks. Based on the above, interpretation of these meta-analyses should be carried out with care. Future supplementation studies should take into consideration all these population and methodological issues by incorporating them in their research design and settings.

Concentration of 25-hydroxyvitamin D from neonatal dried blood spots and the relation to gestational age, birth weight and Ponderal Index: the D-tect study

“…Conflicting findings on this association are, however, present in the literature. Narrative and systematic reviews and meta-analyses indicate that an association between 25(OH)D and the risk of SGA from observational studies exist, but not from randomised trials (20,(46)(47)(48) . The discrepant results might be owing to differences in study designs, exposure and/or outcome definitions and measurements, as well as study populations.…”

Maternal and Pediatric Health Outcomes in relation to Gestational Vitamin D Sufficiency

“…(iii) Different types of vitamin D (vitamin D 2 versus vitamin D 3 ) have different physiological impact. And (iv) various methodological concerns are evident [ 46 ], such as the lack of standardized assays.…”

Vitamin D heritability and effect of pregnancy status in Vervet monkeys (Chlorocebus aethiops sabaeus) under conditions of modest and high dietary supplementation

“…There is also contradictory evidence regarding the associations between maternal vitamin D status and bone development in offspring, while supplementation studies with vitamin D have shown improvement in neonatal calcium homeostasis (Karras et al, 2014, 2015). The mechanism for the beneficial effects of vitamin D on the adult skeletal health has been documented, but the adverse effects and role in non-bone health outcomes in pregnancy remains unclear (Brannon 2012; Glendenning and Inderjeeth 2015).…”

“…Studies have reported that the typically low vitamin D concentrations found in pregnant versus non-pregnant women are further associated with multiple potentially adverse maternal (pregnancy induced hypertension, preeclampsia, gestational diabetes, infectious and inflammatory disorders), foetal (gestational duration), and infant (juvenile diabetes, developmental and psychological disorders) outcomes (Dror, 2011;Dawodu and Akinbi, 2013;Karras et al, 2014). There is also contradictory evidence regarding the associations between maternal vitamin D status and bone development in offspring, while supplementation studies with vitamin D have shown improvement in neonatal calcium homeostasis (Karras et al, 2014(Karras et al, , 2015. The mechanism for the beneficial effects of vitamin D on the adult skeletal health has been documented, but the adverse effects and role in non-bone health outcomes in pregnancy remains unclear (Brannon, 2012;Glendenning and Inderjeeth, 2015).…”