French prenatal Vitamin D recommended supplementation: Enough or not?

Prenatal Vitamin D Deficiency and Maternal and Fetal Health Outcomes

Vitamin D deficiency (VDD) is a significant health issue that could have serious implications for the well-being of women and their offspring. Prenatal vitamins are widely used, but deficiency still occurs frequently in the preconception period, during pregnancy, and in breastfed infants. We analyzed the association between prenatal VDD and maternal and fetal health outcomes by reviewing studies conducted in Europe. The literature was searched for articles published in the last 10 years focusing on preeclampsia, gestational diabetes mellitus, preterm birth, low birth weight, asthma, and autism spectrum disorder. We identified a total of 43 review articles, 31 original articles, and two guidelines. During pregnancy, VDD is associated with a higher likelihood of developing gestational diabetes mellitus and preeclampsia. It may also lead to an increase in the risk of preterm birth, low birth weight, as well as asthma, and autism spectrum disorder in the offspring. While the official guidelines for vitamin D dosage differ in various countries, health authorities usually recommend a total daily supplement intake of 400-2,000 IU. In conclusion, this review emphasizes the importance of establishing guidelines for vitamin D supplementation as well as the requirement of official standards for the consumption of vitamin D in the prenatal period. Future research should concentrate on developing more unified approaches to vitamin D assessment and establishing preventative measures that can be incorporated into prenatal care programs.

Longitudinal Assessment of Serum 25-Hydroxyvitamin D Levels during Pregnancy and Postpartum-Are the Current Recommendations for Supplementation Sufficient?

(1) Background: Pregnant women are at risk of vitamin D deficiency. Data on pregnancy outcomes in women with vitamin D deficiency during pregnancy are controversial, and prospective longitudinal data on vitamin D deficiency with consistent definitions in pregnant women are scarce. (2) Methods: The aim of this prospective longitudinal cohort study was to investigate 25-hydroxyvitamin D levels over the course of pregnancy and postpartum in singleton and twin pregnancies with regard to dietary and supplemental vitamin D intake and environmental factors influencing vitamin D levels, evaluated by a standardized food frequency questionnaire. (3) Results: We included 198 healthy singleton and 51 twin pregnancies for analysis. A total of 967 study visits were performed over a 3-year period. Overall, 59.5% of pregnant women were classified as vitamin D deficient in the first trimester, 54.8% in the second trimester, 58.5% in the third trimester, 66.9% at birth, and 60% 12 weeks postpartum, even though 66.4% of the study population reported daily pregnancy vitamin intake containing vitamin D. Dietary vitamin D intake did not affect vitamin D levels significantly. (4) Conclusions: The majority of pregnant women evaluated in this study were vitamin D deficient, despite administration of pregnancy vitamins containing vitamin D. Individualized vitamin D assessment during pregnancy should be considered to ensure adequate supplementation and prevention of hypovitaminosis D.

Two cases of fractures in neonates associated with maternofetal vitamin D deficiency

Vitamin D supplementation is essential for the entire population, especially during pregnancy and in the pediatric period. We report two case studies of full-term newborns who presented long-bone fractures associated with severe vitamin D deficiency transmitted to them by their mothers, even though maternal supplementation had been implemented according to the existing recommendations. These observations encourage the investigation of neonatal vitamin D deficiency in the presence of long-bone fractures in the absence of traumatic birth and the necessity of reenforcing the means of prevention and the selection of risk groups in order to adjust vitamin D supplementation during pregnancy individually.

Maternal factors associated with neonatal vitamin D deficiency

Background An adequate maternal vitamin D (vitD) intake is rarely achieved in actual practice. The aim of this study was to assess maternal factors associated with neonatal vitD deficiency. Methods This is a single-institution prospective case-control study. Consecutive single-birth neonates admitted between September 2014 and February 2015 were prospectively enrolled. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were measured by spectrometry. The associations between neonatal vitD deficiency (defined as 25(OH)D <15 ng/mL) and several maternal characteristics, including body mass index (BMI) at delivery, education, health insurance status, birth season, sun exposure time, egg consumption, and vitD supplementation during pregnancy, were examined using multivariable logistic regression and their respective odds ratios (ORs) reported. Results A total of 125 mother-infant dyads were enrolled, with a gestational age of 36.8±2.7 weeks. Fifty-six percent (70/125) of the neonates had vitD deficiency. Maternal factors that were significantly associated with vitD deficiency included winter birth, insufficient sun exposure time, high maternal BMI at delivery, insufficient egg consumption, insufficient vitD supplementation during pregnancy, and disadvantaged health insurance. Disadvantaged insurance status and insufficient vitD supplementation during pregnancy were the two most influential factors of neonatal vitD deficiency, with an OR of 7.5 (95% confidence interval [CI], 2.0-37.6) and 7.0 (95% CI, 2.7-20.7), respectively. Conclusions Neonatal vitD deficiency is very rampant. An individualized vitD supplementation strategy may be developed by taking into consideration pregnant women's socioeconomic status and lifestyles.

The role of vitamin D in perinatology. An up-to-date review

The role of vitamin D in perinatology is a subject of major interest in current medicine. There is growing evidence about the role of maternal vitamin D levels in pregnancy outcomes. The aim of this review is to summarize the current literature about the role of vitamin D in perinatology. Evidence from this review suggests associations between low levels of maternal vitamin D and higher risk of certain obstetrical complications. Vitamin D has been found to be related to preeclampsia, gestational diabetes mellitus, low birth weight, and preterm birth. The current literature supports vitamin D supplementation in pregnant women, but more high-quality data are necessary. The problem that remains is how to achieve an optimal 25-hydroxyvitamin D level. To determine the real benefits of vitamin D supplementation in pregnancy, we need high-quality trials in larger groups.

Cord-blood vitamin D level and night sleep duration in preschoolers in the EDEN mother-child birth cohort

OBJECTIVE

Deficiency in 25-hydroxyvitamin D (25OHD) has been associated with sleep disorders in adults. Only three cross-sectional studies were performed in children; which showed an association between 25OHD deficiency and both obstructive sleep apnea syndrome and primary snoring. No longitudinal study has been performed in children from the general population. We analyzed the association between cord-blood vitamin D levels at birth and night-sleep duration trajectories for children between 2 and 5-6 years old in a non-clinical cohort.

METHOD

We included 264 children from the French EDEN mother-child birth-cohort with cord-blood 25OHD level determined by radio-immunoassay at birth, and night-sleep trajectories for children between 2 and 5-6 years old obtained by the group-based trajectory modeling method. Associations between 25OHD and sleep trajectories were assessed by multinomial logistic regression adjusted for maternal and child characteristics.

RESULTS

The trajectories short sleep (<10h30/night), medium-low sleep (10h30-11h00/night), medium-high sleep (≈11h30/night), long sleep (≥11h30/night) and changing sleep (decreased from ≥11h30 to 10h30-11h00/night) represented 5%, 46%, 37%, 4% and 8% of the children, respectively. The mean 25OHD level was 19 ng/ml (SD = 11, range 3-63). It was 12 (SD = 7), 20 (SD = 11), 19 (SD = 10), 14 (SD = 7) and 16 (SD = 8) ng/ml for children with short, medium-low, medium-high, long and changing sleep trajectories, respectively. On adjusted analysis, for each 1-ng/ml decrease in 25OHD level, the odds of belonging to the short sleep versus medium-high sleep trajectory was increased (odds ratio = 1.12, 95% confidence interval [1.01-1.25]). We found no other significant association between 25OHD level and other trajectories.

CONCLUSION

A low 25OHD level at birth may be associated with an increased probability of being a persistent short sleeper in preschool years. These results need confirmation.

Prevalence and determinants of vitamin D deficiency in the third trimester of pregnancy: a multicentre study in Switzerland

Vitamin D deficiency during pregnancy is associated with negative health consequences for mothers and their infants. Data on the vitamin D status of pregnant women in Switzerland are scarce. A three-centre study was conducted in the obstetric departments of Zurich, Bellinzona and Samedan (Switzerland) to investigate the prevalence and determinants of vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D)<50 nmol/l) in 3rd-trimester pregnant women living in Switzerland (n 305), and the correlation between 25(OH)D in pregnant women and their offspring at birth (n 278). Demographic and questionnaire data were used to explore the determinants of vitamin D deficiency. Median concentration of serum 25(OH)D in the third trimester of pregnancy was 46·0 nmol/l (1st-3rd quartiles: 30·5-68·5), representing a 53·4 % prevalence of vitamin D deficiency. 25(OH)D levels in the umbilcal cord blood (median: 50·0 nmol/l; 1st-3rd quartiles: 31·0-76·6) strongly correlated with mothers' serum 25(OH)D (Spearman's correlation ρ=0·79, P<0·001). Multivariable logistic regression analysis showed that significant determinants of vitamin D deficiency in pregnant women were centre of study, country of origin, season of delivery and vitamin D supplement intake. Near-term BMI, skin colour, use of sunscreen and mothers' education, although each not individually significant, collectively improved the ability of the model to explain vitamin D status. Low vitamin D levels were common in this sample of pregnant women and their newborns' cord blood. Vitamin D supplement intake was the most actionable determinant of vitamin D status, suggesting that vitamin D supplementation during pregnancy should receive more attention in clinical practice.

Comparative analysis of nutritional guidelines for vitamin D

Vitamin D is essential for calcium and bone homeostasis. Humans are largely dependent on UVB-radiation-induced photosynthesis of vitamin D, as few foods contain vitamin D. However, the same radiation that produces vitamin D is also carcinogenic, albeit with a long lag time, and causes DNA damage. In view of the increasing life expectancy, avoiding excessive sun exposure is prudent. Several groups of people have a shortfall between their requirements for vitamin D and their combined endogenous synthesis and intake from natural foods, and therefore need vitamin D supplementation. Governments and scientific societies are regularly updating their recommendations for intake of vitamin D, especially for groups that should (infants) or prefer to (especially elderly individuals) avoid direct sunlight. An overview of such guidelines is presented in this Review. A fairly large consensus exists that all infants should receive 400 international units (IU) (10 μg) daily during their first year of life and that elderly individuals should have access to vitamin D supplementation (at recommended dosages varying from 400 IU to 800 IU daily in most governmental guidelines but at higher dosages in other guidelines). All guidelines unanimously agree that serum levels of 25-hydroxyvitamin D (25OHD) <25 nmol/l (10 ng/ml) should be avoided at all ages. Children and adults who have limited sun exposure should receive vitamin D supplementation, but the recommended doses vary widely (from 200 IU to 2,000 IU daily), in line with disagreement regarding the minimal desirable serum concentration of 25OHD (which varies from 25 nmol/l to >100 nmol/l).