Maternal vitamin D status, gestational diabetes and infant birth size

Helena H Hauta-Alus,Timo K Hytinantti,Jenni Rosendahl,Maria Enlund-Cerullo,Elisa M Holmlund-Suila,Heli T Viljakainen,Saara M Valkama,Outi M Mäkitie,Sture Andersson,Otto M Helve

doi:10.1186/s12884-017-1600-5

Abstract

BackgroundMaternal vitamin D status has been associated with both gestational diabetes mellitus (GDM) and fetal growth restriction, however, the evidence is inconsistent. In Finland, maternal vitamin D status has improved considerably due to national health policies. Our objective was to compare maternal 25-hydroxy vitamin D concentrations [25(OH)D] between mothers with and without GDM, and to investigate if an association existed between maternal vitamin D concentration and infant birth size.MethodsThis cross-sectional study included 723 mother-child pairs. Mothers were of Caucasian origin, and infants were born at term with normal birth weight. GDM diagnosis and birth size were obtained from medical records. Maternal 25(OH)D was determined on average at 11 weeks of gestation in pregnancy and in umbilical cord blood (UCB) at birth.ResultsGDM was observed in 81 of the 723 women (11%). Of the study population, 97% were vitamin D sufficient [25(OH)D ≥ 50 nmol/L]. There was no difference in pregnancy 25(OH)D concentration between GDM and non-GDM mothers (82 vs 82 nmol/L, P = 0.99). Regression analysis confirmed no association between oral glucose tolerance test results and maternal 25(OH)D (P > 0.53). Regarding the birth size, mothers with optimal pregnancy 25(OH)D (≥ 80 nmol/L) had heavier newborns than those with suboptimal pregnancy 25(OH)D (P = 0.010). However, mothers with optimal UCB 25(OH)D had newborns with smaller head circumference than those with suboptimal 25(OH)D (P = 0.003), which was further confirmed as a linear association (P = 0.024).ConclusionsMaternal vitamin D concentration was similar in mothers with and without GDM in a mostly vitamin D sufficient population. Associations between maternal vitamin D status and birth size were inconsistent. A sufficient maternal vitamin D status, specified as 25(OH)D above 50 nmol/L, may be a threshold above which the physiological requirements of pregnancy are achieved.Trial registrationThe project protocol is registered in ClinicalTrials.gov in November 8, 2012 (NCT01723852).

Highlights

Maternal vitamin D status has been associated with both gestational diabetes mellitus (GDM) and fetal growth restriction, the evidence is inconsistent
Poor maternal vitamin D status has been related to fetal growth restriction [15] but it is unknown whether maternal vitamin D status associates with birth size in infants with normal birth weight
Many of the findings regarding the relationship between vitamin D deficiency and GDM are based on case-control studies, which may include a potential selection bias

Summary

Introduction

Maternal vitamin D status has been associated with both gestational diabetes mellitus (GDM) and fetal growth restriction, the evidence is inconsistent. Our objective was to compare maternal 25-hydroxy vitamin D concentrations [25(OH)D] between mothers with and without GDM, and to investigate if an association existed between maternal vitamin D concentration and infant birth size. Poor maternal vitamin D status has been related to fetal growth restriction [15] but it is unknown whether maternal vitamin D status associates with birth size in infants with normal birth weight. The objectives of the present study were to compare 25(OH)D concentration at two consecutive time points between mothers with and without GDM, and to investigate associations between maternal factors and infant’s birth size, and the potential role of 25(OH)D concentration therein

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