Vitamin D inadequacy in pregnancy: biology, outcomes, and interventions

Maternal vitamin D and growth of under-five children: a systematic review and meta-analysis of observational and interventional studies

Background

Even though previous systematic reviews have reported on the role of prenatal vitamin D on birth outcomes, its effect on child growth is poorly understood.

Objective

To synthesize a systematic summary of the literature on the effect of maternal vitamin D supplementation on the linear growth of under-five children.

Method

This study includes studies (both observational and interventional with a control group) that evaluated the effects of prenatal vitamin D status on child linear growth. The mean child length/length for age with 95% confidence interval (CI) was pooled as the weighted mean difference using a random-effects model. A funnel plot was used to assess potential publication bias.

Results

A total of 45 studies and 66 reports covering a total population of 44,992 (19,683 intervention or high vitamin D group, and 25,309 control or low vitamin D group) were analyzed. Studies spanned from 1977 to 2022. The pooled weighted mean difference was 0.4 cm (95% CI: 0.15–0.65). A subgroup analysis, based on vitamin D supplementation frequency, showed that mothers who supplemented monthly or less frequently had a 0.7 cm (95% CI: 0.2–1.16 cm) longer child. Supplementation with a dose of >2000 international units increased child length at birth. The weighted mean difference was 0.35 cm (95% CI: 0.11–0.58).

Conclusion

The evidence from this review shows that maternal supplementation of vitamin D is associated with increased birth length. This is apparent at higher doses, low frequency (monthly or less frequent), and during the second/third trimester. It appears that vitamin D supplementation during pregnancy is protective of future growth in under-five children. Clinical trials are needed to establish evidence of effectiveness for the frequency and dose of supplementation.

Vitamin D deficiency and associated factors among antenatal care attending pregnant women in Sodo town, South Ethiopia: A facility-based cross-sectional study

BACKGROUND

Vitamin D deficiency is an emerging public health problem globally, with devastating health consequences. Pregnant women are most susceptible for Vitamin D deficiency, and black women particularly are under double burden of the problem. Therefore, this study aimed to determine the prevalence of Vitamin D deficiency and identify associated factors among antenatal care attending pregnant women.

METHODS

A facility-based cross-sectional study involving 331 pregnant women was conducted from March to April in 2021. Systematic random sampling technique was used to select the study participants from antenatal care service providing facilities. Data were collected by using interviewer-administered questionnaire and 5ml of blood sample was collected using aseptic techniques. Data were entered into Epi Data software version 3.1 and exported to SPSS version 20 for analysis. Binary logistic regression analysis was used to identify the associated factors.

RESULTS

In this study, about 39% of the women were Vitamin D deficient; of which 8.8% were severely deficient. The mean serum Vitamin D level was 24.43ng/ml. Women with Body Mass Index (BMI) ≥30 (AOR = 47.31; 95% CI: 3.94, 567.70) and who never ate egg had a higher chance of being Vitamin D deficient (AOR = 7.48; 95% CI: 1.02, 55.05). On the other hand, women who were exposed to mid-day time sunlight (AOR = 0.30; 95% CI: 0.11, 0.77) were less likely to become Vitamin D deficient.

CONCLUSIONS

Vitamin D deficiency is higher among obese women and women who did not consume egg. Being exposed to mid-day sunlight is protective against Vitamin D deficiency. Having optimal body weight, mid-day sun light exposure and consumption of Vitamin D rich diet might contribute to reduce the risk of Vitamin D deficiency.

Vitamin D and parathyroid hormone in the umbilical cord blood - Correlation with light and dark maternal skin color

During pregnancy, vitamin D deficiency is associated with negative health consequences for mother and child. Furthermore, dark skin color is associated with lower vitamin D levels. We investigated 25-hydroxy-vitamin D (25(OH)D) and parathyroid hormone (PTH) levels in mothers and in cord blood of their newborns depending on maternal skin color. We recruited 202 mother and child pairs at the University Hospital Zurich and measured 25(OH)D and PTH concentrations in maternal and postpartum umbilical cord blood. Skin type was self-reported based on the Fitzpatrick Scale (type I to V). Uni- and multivariate methods were used to compare the maternal and neonatal 25(OH)D and PTH levels by skin type (light: I-III vs. dark: IV-V). As many as 54.5% of all mothers and 41.1% of the neonates were 25(OH)D deficient. This was higher in the neonates of dark-skinned (55.9%) than in the neonates of light-skinned mothers (38.1%; p = .06). The correlation of 25(OH)D in the maternal with umbilical cord blood was high (light: r = 0.85, dark: r = 0.87), with higher concentrations of 25(OH) vitamin D in the umbilical cord than in maternal blood. Regression analysis revealed that country of origin and maternal 25(OH)D concentration were the only statistically significant determinants for umbilical cord blood 25(OH)D. We observed no correlation of maternal with umbilical cord PTH concentrations; median PTH concentrations in the umbilical cord (5.6 pg/ml) were significantly lower than in maternal blood (25.7 pg/ml). The recommendation of vitamin D supplementation in newborns in their first 3 years of life should be particularly emphasized to dark-skinned mothers.

Review: Influence of 25(OH)D Blood Concentration and Supplementation during Pregnancy on Preeclampsia Development and Neonatal Outcomes

Briefly, 25-hydroxyvitamin D (25(OH)D) plays an essential role in embryogenesis and the course of intra- and postnatal periods and is crucially involved in the functioning of the mother-placenta-fetus system. The low quantity of 25(OH)D during pregnancy can lead to an elevated risk for preeclampsia occurrence. Despite the numerous studies on the association of 25(OH)D deficiency and preeclampsia development, the current research on this theme is contradictory. In this review, we summarize and analyze study data on the effects of 25(OH)D deficiency and supplementation on pregnancy, labor, and fetal and neonatal outcomes.

Maternal and Neonatal Vitamin D Binding Protein Polymorphisms and 25-Hydroxyvitamin D Cutoffs as Determinants of Neonatal Birth Anthropometry

Background: Vitamin D-binding protein (VDBP) is a vital regulator of optimal vitamin D homeostasis and bioavailability. Apart from its well-documented role as a key component in vitamin D dynamic transfer and circulation, it has a myriad of immunoregulatory functions related to innate immunity, which becomes particularly critical in states of increased immunological tolerance including pregnancy. In this regard, VDBP dyshomeostasis is considered to contribute to the development of several fetal, maternal, and neonatal adverse outcomes. However, precise physiological pathways, including the contribution of specific VDBP polymorphisms behind such phenomena, are yet to be fully deciphered. Our aim was to assess the combined effect of maternal and neonatal VDBP polymorphism heterogeneity in conjunction with different maternal and neonatal 25(OH)D cutoffs on the neonatal anthropometric profile at birth. Methods: The study included data and samples from a cohort of 66 mother–child pairs at birth. The inclusion criterion was full-term pregnancy (gestational weeks 37–42). Neonatal and maternal 25(OH)D cutoffs were included according to vitamin D status at birth and delivery. Concentrations of 25(OH)D2 and 25(OH)D3 were measured using liquid chromatography–tandem mass spectrometry. Results: The upper arm length of neonates with 25(OH)D ≤ 25 nmol/L was higher in neonate CC carriers for rs2298850. The upper thigh neonatal circumference was also higher in the ones with either 25(OH)D ≤ 50 or ≤75 nmol/L in rs2298850 CG + GG or rs4588 GT + TT carriers. We did not observe any significant effect for maternal VDBP polymorphisms nor for birth maternal 25(OH)D concentrations, on birth neonatal anthropometry. Conclusions: Our findings emphasize a potential role for neonatal VDBP genotypes rs2298850 and rs4588, in conjunction with specific neonatal 25(OH)D cutoffs, in the range of sufficiency on neonatal growth and development.

Effect of PM2.5 exposure on Vitamin D status among pregnant women: A distributed lag analysis

BACKGROUND

Serum vitamin D levels are associated with exposure to air pollution, however, the lagged effect of exposure to air pollution remains unknown in pregnant women.

METHODS

Pregnant women who delivered at a maternity center in Shanghai, China, from 2015 to 2019 were included in the present study. The concentration of particulate matter 2.5 (PM_2.5) before 25-Hydroxyvitamin D [25(OH)D] detection was estimated using the satellite-based grid models. The distributed lag non-linear models were performed to examine the lagged association between weekly-specific PM_2.5 exposure and vitamin D deficiency (VDD) or serum 25(OH)D levels.

RESULTS

Among the 58,025 pregnant women included in the study (mean age at conception, 30.77 ± 3.75 years; mean prepregnancy BMI, 21.09 ± 2.55 kg/m²), 61.32% were diagnosed with VDD. Weekly-specific PM_2.5 exposure at weeks 1-10 before the detection of 25(OH)D was significantly associated with an increased incidence of VDD (p < 0.05). For every 10 μg/m³ increase in PM_2.5 exposure, the serum 25(OH)D level decreased by 1.346 nmol/L (95%CI: 1.183-1.508 nmol/L). The association between average PM_2.5 exposure and VDD at 1-10 weeks was more significant in weather conditions with low mean sunshine hours (OR: 1.246, 95%CI: 1.221-1.271).

CONCLUSION

Our study provided suggestive evidence that PM_2.5 exposure at 1-10 weeks before the 25(OH)D detection may decrease the circulating 25(OH)D levels in pregnant women and increase VDD risk in pregnant women. More attention should be paid to the long-term impact of PM_2.5, in particular, during weather conditions with a relatively short duration of sunshine.

Evaluation of Maternal and Infantile Levels of Vitamin D in Preterm Infants

INTRODUCTION

Vitamin D deficiency is highly prevalent during pregnancy and in premature infants. This study was done to investigate the maternal and infantile levels of vitamin D in preterm infants.

METHODS

Using available sampling during 2018-2020, the maternal and umbilical cord serum levels of vitamin D were measured in 294 premature infants in Ghaem Hospital, Mashhad, Iran. A researcher- made questionnaire consisting of neonatal demographic and clinical characteristics was used as the data collection tool. Both maternal and placental vitamin D levels were categorized into four classes: severe deficiency (vitamin D<10 ng/ml), moderate deficiency (10.1≤vitamin D≤20 ng/ml), mild deficiency (20.1≤vitamin D≤30 ng/ml) and normal (vitamin D >30.1ng ml).

RESULTS

Vitamin D deficiency was seen in 89% of premature infants (46.6% severe, 30.6% moderate, and 11.9% mild). Serum levels of vitamin D were 18.28±13.94 ng/ml and 14.10±9.70 ng/ml in mothers and infants, respectively. The infants below and above 32 weeks exhibited vitamin D values of 10.97±6.31 ng/ml and 18.05±11.64 ng/ml, respectively. The difference in vitamin D levels between boys (12.59±8.40 ng/ml) and girls (16.05±11.45 ng/ml) was found to be significant (P=0.009). Moderate and severe vitamin D deficiency was more common at earlier pregnancy ages (P=0.001).

CONCLUSION

Vitamin D deficiency is more common and severe in preterm infants and their mothers. Controlling vitamin D levels during pregnancy, especially in women at risk of preterm labor and preterm infants, may help reduce prematurity problems.

Could Vitamin D Be Effective in Prevention of Preeclampsia?

Prevention of preeclampsia (PE) remains one of the most significant problems in perinatal medicine. Due to the possible unpredictable course of hypertension in pregnancy, primarily PE and the high complication rate for the mother and fetus/newborn, it is urgent to offer pregnant women in high-risk groups effective methods of preventing the PE development or delaying its appearance. In addition, due to the association of PE with an increased risk of developing cardiovascular diseases (CVD) in later life, effective preeclampsia prevention could also be important in reducing their incidence. Ideal PE prophylaxis should target the pathogenetic changes leading to the development of PE and be safe for the mother and fetus, inexpensive and freely available. Currently, the only recognized method of PE prevention recommended by many institutions around the world is the use of a small dose of acetylsalicylic acid in pregnant women with risk factors. Unfortunately, some cases of PE are diagnosed in women without recognized risk factors and in those in whom prophylaxis with acetylsalicylic acid is not adequate. Hence, new drugs which would target pathogenetic elements in the development of preeclampsia are studied. Vitamin D (Vit D) seems to be a promising agent due to its beneficial effect on placental implantation, the immune system, and angiogenic factors. Studies published so far emphasize the relationship of its deficiency with the development of PE, but the data on the benefits of its supplementation to reduce the risk of PE are inconclusive. In the light of current research, the key issue is determining the protective concentration of Vit D in a pregnant woman. The study aims to present the possibility of using Vit D to prevent PE, emphasizing its impact on the pathogenetic elements of preeclampsia development.

Relationship of maternal obesity and vitamin D concentrations with fetal growth in early pregnancy

Purpose

To evaluate the effects of the association between first trimester vitamin D (VitD) concentrations and increased prepregnancy body mass index (BMI) on early fetal growth restriction (FGR).

Methods

This retrospective cohort study included 15,651 women with singleton pregnancy who delivered at the International Peace Maternity and Child Health Hospital between January 2015 and November 2016. Women were classified in two groups based on their serum 25(OH)D vitamin levels status: VitD sufficient (SUFF) group and VitD insufficient or deficient (INSUFF/DEF). The cut-off point for VitD concentration was 50.00 nmol/L. Comparisons were made between women with normal prepregnancy body weight (BMI 18.5–23.9 kg/m²) and overweight and obese (OWO) women (BMI > 24.0 kg/m²). Early FGR was defined as first-trimester gestational age-adjusted crown-rump length (CRL) in the lowest 20th centile of the population. Multivariate logistic regression was used to evaluate the association between maternal serum 25(OH)D levels and prepregnancy BMI with first trimester CRL and early FGR.

Results

In VitD INSUFF/DEF group, the first trimester CRL was decreased (P = 0.005), and the risk of early FGR was increased by 13% (95% CI 1.04–1.24, P = 0.004) compared to the VitD SUFF group. In OWO group, the first trimester CRL was also significantly decreased (P < 0.0001), and the risk of early FGR was significantly increased by 58% (95% CI 1.40–1.78, P < 0.001) compared with normal weight group. Furthermore, there was a significant combined effect of maternal VitD concentrations and OWO on CRL (P for interaction = 0.02) and the risk of early FGR (P for interaction = 0.07).

Conclusion

Sufficient first trimester serum 25(OH)D concentration was a protective factor for early fetal growth, especially among OWO mothers. Chinese Clinical Trial Registry (Registration number: ChiCTR1900027447 with date of registration on November 13, 2019-retrospectively registered).

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02695-w.

Ramadan Fasting during Pregnancy and Health Outcomes in Offspring: A Systematic Review

Ramadan is one of the five pillars of Islam, during which fasting is obligatory for all healthy individuals. Although pregnant women are exempt from this Islamic law, the majority nevertheless choose to fast. This review aims to identify the effects of Ramadan fasting on the offspring of Muslim mothers, particularly on fetal growth, birth indices, cognitive effects and long-term effects. A systematic literature search was conducted until March 2020 in Web of Science, Pubmed, Cochrane Library, Embase and Google Scholar. Studies were evaluated based on a pre-defined quality score ranging from 0 (low quality) to 10 (high quality), and 43 articles were included. The study quality ranged from 2 to 9 with a mean quality score of 5.4. Only 3 studies had a high quality score (>7), of which one found a lower birth weight among fasting women. Few medium quality studies found a significant negative effect on fetal growth or birth indices. The quality of articles that investigated cognitive and long-term effects was poor. The association between Ramadan fasting and health outcomes of offspring is not supported by strong evidence. To further elucidate the effects of Ramadan fasting, larger prospective and retrospective studies with novel designs are needed.

Vitamin D Levels in Mother-Baby Pairs: A Cross-Sectional Prospective Study in a Rwandan Tertiary Hospital

BACKGROUND

Exposure to the sunlight contributes largely to the production of vitamin D. However, vitamin D deficiency is a reality in tropical countries, despite enjoying enough sunlight, especially bearing women in their last trimester whose foetuses exclusively depend on their reserves. This work aimed at demonstrating the state of vitamin D in mother-baby pairs and associated factors in one of the University Hospitals in Rwanda.

METHODS

This cross-sectional prospective study was performed on mother-baby pairs at Kigali University Hospital. Mother's serum 25-hydroxyvitamin D levels were considered as outcomes compared with demographic, clinical and biological markers. Correlation analysis was conducted in order to assess the association between serum 25-hydroxyvitamin D levels for the couple mothers-babies.

RESULTS

Approximately 38% of women and 65% of neonates had deficiency in 25-hydroxyvitamin D (<20 ng/ml). The use of a vitamin D rich diet within 24 h recall (p < 0.01) or 1 week recall (p < 0.001) before delivery was associated with appropriate vitamin D levels in mothers. Interestingly, a strong positive correlation was found between maternal and neonatal serum 25-hydroxyvitamin D levels (r = 0.760).

CONCLUSIONS

There was a high rate of vitamin D deficiency in mothers and their babies. Babies born from women with deficiency were likely to develop low levels of vitamin D. This stresses on the need to strengthen the interventions for preventing vitamin D deficiency in the couple mothers-babies such as supplement in vitamin D before and after delivery, improving the quality of meals and regular contact with sunlight.

A joint medico-historical and paleopathological perspective on vitamin D deficiency prevalence in post-Medieval Netherlands

OBJECTIVE

By applying a joint medico-historical and paleopathological perspective, this paper aims to improve our understanding of factors influencing past vitamin D deficiency in ten Dutch 17th to 19th-century communities of varying socioeconomic status and settlement type.

MATERIALS

Vitamin D deficiency is evaluated in 733 individuals of both sexes and all age groups: Silvolde (n = 16), Rotterdam (n = 23), Rhenen (n = 24), Noordwijkerhout (n = 27), Gouda1and 2 (n = 40; n = 59), Roosendaal (n = 51), Den Haag (n = 93), Hattem (n = 113), and Beemster (n = 287).

METHODS

Rickets and residual rickets are macroscopically assessed using established criteria. Hypotheses formulated based on medico-historical texts are investigated via multivariate statistical analysis of vitamin D deficiency prevalence.

RESULTS

Vitamin D deficiency prevalence ranges from 13.7 % (7/51) in Roosendaal to 48.1 % (13/27) in Noordwijkerhout, with an onset of < 4 years, and higher rates in cities, conforming to medico-historical texts. Patterns of child labor are likely key. In contrast, socioeconomic status did not statistically significantly influence vitamin D deficiency prevalence rates.

CONCLUSION

Systematically collected paleopathological data enabled evaluation of medico-historical texts and provided insights into the role that socioeconomic status and settlement type played on the prevalence of vitamin D deficiency.

SIGNIFICANCE

Combining medico-historical texts and large-scale paleopathological data enables disease patterning to be embedded in a comprehensive biocultural perspective.

LIMITATIONS

Comparisons may be limited by the small sample size of high socioeconomic status nonadults and some of the collections.

SUGGESTIONS FOR FUTURE RESEARCH

Analysis of more individuals and sites would improve our understanding of disease patterns.

Prevalence of calcium and vitamin D deficiency and their association with feto-maternal outcomes in a sample of Iranian pregnant women

BACKGROUND

Calcium and vitamin D deficiency is common among Iranian women of childbearing age and poses adverse effects on pregnancy outcomes. The aim of the current study was to determine the prevalence of vitamin D and calcium in a sample of Iranian pregnant women and to assess its correlation with the feto-maternal outcomes.

METHODS

In this prospective cross-sectional study, a sample of pregnant women between 15 to 45 years who were in the third trimester were recruited from a number of hospitals in Tehran. Data were collected by the means of a self-developed questionnaire, interviews, physical examination, and paraclinical tests including measuring the serum level of calcium, vitamin D, parathormone (PTH) and phosphorous (Pi). The questionnaire obtained information on age, level of education, socio-economic status, parity, gravidity, calcium intake during pregnancy, as well as feto-maternal outcomes.

RESULTS

We included a total number of 233 singleton pregnancies. Most of the subjects (58.4%) had vitamin D deficiency and 12.0% suffered from severe vitamin D deficiency. Vitamin D deficiency was adversely associated with the years of education (p= 0.007), serum level of parathormone (p< 0.001). The Metabolic Equivalent of Task (MET) (p< 0.001), the exercise sequence per week (p< 0.001), sun exposure (p< 0.001), higher rate of sunscreen usage (p= 0.011) and higher BMI (p= 0.005). Vitamin D deficiency was associated with higher rate of cesarean delivery (p= 0.024), higher rate of diastolic hypertension (p= 0.019), higher rate of neonatal jaundice (p= 0.009) and higher rate of neonatal respiratory infections (p< 0.001). Serum level of PTH was a significant risk factor for severe vitamin D deficiency while calcium D supplementation, MET and sunscreen were significant protective factors.

CONCLUSION

The prevalence of vitamin D deficiency during pregnancy among Iranian women is extremely high and is associated with adverse pregnancy outcomes including cesarean delivery, neonatal jaundice and neonatal respiratory infections. Low vitamin D supplementation and sun exposure, lack of physical activity and high BMI are the etiologies. Increasing the knowledge along with vitamin D supplementation during the pregnancy is recommended in Iranian population.

Maternal vitamin D status during pregnancy and offspring risk of childhood/adolescent depression: Results from the Avon Longitudinal Study of Parents and Children (ALSPAC)

BACKGROUND

Low maternal vitamin D levels [serum 25-hydroxyvitamin D (25(OH)D)] during pregnancy have been linked to offspring neuropsychiatric outcomes such as schizophrenia and autism, but studies on depression are lacking. We examined the association between maternal vitamin D status during pregnancy and offspring depression during childhood and adolescence and investigated whether any associations were modified by offspring genetic risk for depression.

METHODS

Mother-singleton birth offspring pairs in the Avon Longitudinal Study of Parents and Children (ALSPAC) that had maternal 25(OH)D measurements, offspring genetic data, and offspring depression measures collected in childhood (mean age=10.6 years; n = 2938) and/or adolescence (mean age=13.8 years; n = 2485) were included in the analyses. Using multivariable logistic regression, we assessed associations between maternal vitamin D status and offspring polygenic risk score (PRS) for depression on childhood/adolescent depression risk.

RESULTS

There was no evidence for an association between maternal vitamin D status during pregnancy and offspring depression in childhood (p = 0.72) or adolescence (p = 0.07). Offspring depression PRS were independently associated with childhood depression (p = 0.003), but did not interact with maternal vitamin D status. These results were robust to adjustments for potential confounders and different cut-offs for vitamin D insufficiency/deficiency.

LIMITATIONS

25(OH)D measurements were only available at a single time point during pregnancy.

CONCLUSION

These findings suggest that maternal vitamin D status during pregnancy does not affect an offspring's risk for early life depression.

The Eurasian lactase persistence variant LCT-13910 C/T is associated with vitamin D levels in individuals living at high latitude, more so than exposure to sunlight

Rapid selection of a genetic variant that confers continuous life-long lactase production in Europeans (LCT-13910 C/T) has been attributed to the advantages of acquiring nutrients from consuming milk without the disadvantages of lactose malabsorption. Individuals with this genetic lactase persistence (LP) variant generally consume more milk and have been shown to have higher levels of serum vitamin D. Vitamin D is the principal regulator of Ca absorption and its synthesis in skin is dependent on UVB exposure. The primary aim of the present study was to compare serum vitamin D concentrations with LP variant and to control for UVB exposure. Data from over 100 000 individuals living in Norway, a country with low UVB exposure, was retrospectively retrieved for comparison of genetic LP variant, serum 25-hydroxyvitamin D (25(OH)D) concentration and the time of year when serum samples were taken. For comparison, a similar analysis was performed with a natural dairy micronutrient, namely vitamin B₁₂. It was found that individuals with the genetic LP variant had considerably higher levels of serum 25(OH)D (P < 2 × 10^-16, Cohen's d = 0·73) but lower levels of vitamin B₁₂ (P < 2 × 10^-16, Cohen's d = 0·11), compared with genetic lactase non-persistent individuals, even when controlled for seasonality, age and sex. The difference in serum 25(OH)D levels did not diminish in summer months, showing the role of vitamin D in LP variant selection in areas of low UVB irradiation. LP variant selection advantage through acquiring another dairy micronutrient, vitamin B₁₂, was not observed.

Vitamin D status in preterm neonates and the effects of its supplementation on respiratory distress syndrome

AIM

The aim of this study was to investigate the status and effects of vitamin D supplement as adjuvant therapy in the management of respiratory distress syndrome (RDS) in preterm infants.

PATIENT AND METHODS

Vitamin D was prospectively studied in 196 preterm neonates, 96 of them developed RDS, which further subdivided into three subgroups (subgroup received just conventional therapy, subgroup received conventional therapy plus vitamin D 400 IU/day, and subgroup received conventional therapy plus vitamin D 800 IU/day). The patient selection for each treatment subgroup was done by computed randomization, and all the patients had the same treatment protocols assigned for each subgroup.

RESULTS

The preterm group who developed RDS had lower vitamin D concentrations than the preterm group without RDS (*P < .001). Also, the subgroups supplemented with vitamin D had lower Downes Respiratory Distress score and PaCO2 levels, less duration of hospitalization, and complications rates than the subgroup without vitamin D supplementation. The subgroup supplemented with 800 IU/day vitamin D showed also significantly improvement, less hospitalization duration, and less complications than those supplemented with 400 IU/day.

CONCLUSIONS

25-hydroxyvitamin D concentration was deficient in most preterm babies especially those who developed RDS. Administration of 800 IU/day vitamin D as an adjuvant therapy in cases of RDS was associated with significant decreased in severity, rate of complications, and duration of hospital stay in preterm neonates with RDS.

Association of Sunlight Exposure and Consumption of Vitamin D-Rich Foods During Pregnancy with Adverse Birth Outcomes in an African Population

BACKGROUND

Our objective was to assess whether dietary vitamin D (vitD) intake and sunlight exposure during pregnancy is associated with birth outcomes in a healthy Ghanaian population.

METHODS

A population-based cross-sectional study that included 703 mother-infant pairs accessing postnatal services at the five main health facilities in Cape Coast, Ghana was conducted in 2016. Information on sunlight exposure practices and consumption of vitD-rich foods during pregnancy was collected.

RESULTS

A 1 µg increase in vitD intake resulted in a statistically significant 0.00505 weeks increase in gestational age (95% confidence interval [CI]: 0.00005, 0.01004). Mothers classified in the first quartile of vitD intake had 37% (prevalence ratio = 1.37, 95% CI: 1.10, 1.69) increased risk of preterm birth (PTB) compared to their counterparts classified in the fourth quartile. Decreased vitD intake was also associated with low-to-moderate Apgar score.

CONCLUSION

Nutrition education of mothers on the importance of screening for vitD deficiency during early months of pregnancy is recommended.

The Relationship between First Trimester 25-Hydroxyvitamin D3 Levels and Second Trimester Femur Length and Their Effects on Birth Weight and Length at Birth: A Preliminary Study

Objective

The main goal of our study was to assess relationships between first trimester 25-hydroxyvitamin D3 levels and infant birthweight and length at birth.

Materials and Methods

We conducted a study over our medical records of 154 live-term births at Acibadem Atakent Hospital, Istanbul, Turkey. Subjects were classified into five independent groups.

Results

We retrospectively reviewed a total of 154 live birth records. They took vitamin D3 supplement 1000 U/day. We classified the serum vitamin D levels into 5 groups by concentration. Group 1 comprised serum vitamin D levels <10 ng/ml (n = 41); group 2 comprised serum Vitamin D levels between >10–16 ng/ml (n = 33); group 3 comprised serum vitamin D levels >16–20 ng/ml (n = 26); group 4 vitamin D level between >20–30 ng/ml (n = 33) and group 5 comprised vitamin D levels >30 ng/ml. The femurs of infants were found to be longer between the groups, although the differences were not significant (p=0.054). There was also a statistically significant difference in the neonatal birth weight (p=0.048).

Conclusion

We observed associations between low and high maternal 25-hydroxyvitamin D3 levels and fetal growth at birth weight but no difference in birth length. We conclude that we always need to conduct further research to be able to predict the effects of vitamin D deficiency.

Serum level of 25-hydroxyvitamin D and obesity among early pregnant women

AIM

To assess serum 25-hydroxyvitamin D 25(OH)D level in obese pregnant Sudanese women in early pregnancy.

METHODS

A match case-control study was conducted in Saad Abualila Hospital (Khartoum, Sudan). The cases were obese (body mass index [BMI] ≥ 30.0 kg/m² ) women. Controls were women with normal BMI (18.5-24.9 kg/m² ) matched for age, parity and gestational age. The 25(OH)D level was measured using ELISA.

RESULTS

There was no significant difference between the two groups in their age, parity or gestational age. There was no significant difference in the median (interquartile) level of the serum (25(OH)D between obese pregnant women and normal weight pregnant women (3.05 [11.100-15.937] ng/ml vs 13.05 [10.950-17.362] ng/ml, P = 0.237). There was no significant correlation between BMI and 25(OH)D level (r = -0.133, P = 0.149).

CONCLUSION

There was no significant difference in the 25(OH)D level between the obese pregnant women and normal weight pregnant women in this study.

Micro-CT assessment of dental mineralization defects indicative of vitamin D deficiency in two 17th-19th century Dutch communities

OBJECTIVES

This study investigates vitamin D deficiency patterns in individuals from birth to the beginning of adolescence. Microscopic computed tomography (micro-CT) evaluation of interglobular dentine (IGD) in teeth provides information on the age of disease onset and the number of deficient periods per individual, which will increase our understanding of factors influencing vitamin D deficiency prevalence, including sociocultural practices and latitude.

MATERIALS AND METHODS

Beemster and Hattem, two Dutch 17th-19th century communities, yielded relatively high prevalences of rickets (15-24%) and residual rickets (15-24%). From the affected individuals, a subsample of 20 teeth were selected for micro-CT scanning. Thin sections were made of 17 teeth, consisting of 6 teeth with and 11 teeth without observable IGD on micro-CT that were included for method comparison.

RESULTS

About 19 out of 29 (65.5%) individuals (one tooth was deemed unobservable) presented with IGD on micro-CT. Eight of the 11 (72.7%) individuals without IGD on micro-CT demonstrated histologically visible IGD. In 40.7% (11/27) of the affected individuals (combined micro-CT and histology results), vitamin D deficiency was recurrent, and in four individuals, some episodes occurred at approximately annual intervals suggesting vitamin D deficiency was seasonal. In three individuals, IGD occurred in the dentine formed around birth, suggesting maternal vitamin D deficiency.

DISCUSSION

Micro-CT analysis of IGD is found to be a valuable non-destructive method that can improve our understanding of the influence of sociocultural practices and latitude on disease development within age and sex groups in past communities.

Calcium and vitamin D supplementation and/or periodontal therapy in the treatment of periodontitis among Brazilian pregnant women: protocol of a feasibility randomised controlled trial (the IMPROVE trial)

Background

Periodontitis is a common oral inflammation, which is a risk factor for adverse pregnancy outcomes. Intakes of vitamin D and calcium are inversely associated with occurrence and progression of periodontitis. This study aims to assess the feasibility of a multi-component intervention, including provision of milk powder supplemented with calcium and vitamin D and periodontal therapy (PT), for improving maternal periodontal health and metabolic and inflammatory profiles of low-income Brazilian pregnant women with periodontitis.

Methods

The IMPROVE trial is a feasibility randomised controlled trial (RCT) with a 2 × 2 factorial design with a parallel process evaluation. Pregnant women with periodontitis, aged 18–40 years and with < 20 gestational weeks (n = 120) were recruited and randomly allocated into four groups: (1) fortified sachet (vitamin D and calcium) and powdered milk plus PT during pregnancy, (2) placebo sachet and powdered milk plus PT during pregnancy, (3) fortified sachet (vitamin D and calcium) and powdered milk plus PT after delivery and (4) placebo sachet and powdered milk plus PT after delivery. Dentists and participants are blinded to fortification. Acceptability of study design, recruitment strategy, random allocation, data collection procedures, recruitment rate, adherence and attrition rate will be evaluated. Data on serum levels of vitamin D, calcium and inflammatory biomarkers; clinical periodontal measurements; anthropometric measurements; and socio-demographic questionnaires are collected at baseline, third trimester and 6–8 weeks postpartum. Qualitative data are collected using focus group, for analysis of favourable factors and barriers related to study adherence.

Discussion

Oral health and mineral/vitamin supplementation are much overlooked in the public prenatal assistance in Brazil and of scarcity of clinical trials addressing these issues in low and middle-income countries,. To fill this gap the present study was designed to assess the feasibility of a RCT on acceptability of a multi-component intervention combining conventional periodontal treatment and consumption of milk fortified with calcium-vitamin D for improving periodontal conditions and maternal metabolic and inflammation status, among Brazilian low-income pregnant women with periodontitis. Thus, we hope that this relatively low-cost and safe multicomponent intervention can help reduce inflammation, improve maternal periodontal health and metabolic profile and consequently prevent negative gestational outcomes.

Trial registration

NCT, NCT03148483. Registered on May 11, 2017.

Maternal risk factors and newborn infant vitamin D status: a scoping literature review

Low vitamin D (VitD) status is common among newborn infants, more so in temperate latitudes with evidence that maternal VitD deficiency is a major risk factor given that the neonate relies solely on maternal-fetal transfer of VitD. This scoping review was conducted to provide an overview of the latest evidence from studies regarding the impact of maternal risk factors on infant 25-hydryoxyvitamin D [25(OH)D] concentrations with a focus on studies in Canada and the United States. Several maternal risk factors that contribute to low maternal-fetal 25(OH)D concentrations have been reported over many decades, but no clear pattern has been established for multiethnic populations. For example, darker skin pigmentation and ethnicity are common risk factors for low VitD status. Studies in predominantly white women showed that supplementation of VitD during pregnancy causes significant increases in maternal serum 25(OH)D which often improves cord serum 25(OH)D values. In addition, VitD recommendations by health care professionals and adherence to supplementation by pregnant women appear to positively influence maternal and infant 25(OH)D concentrations. Conversely, winter season, obesity, lower socioeconomic status including lifestyle factors (smoking), and use of medication pose risk for lower maternal-fetal transfer of VitD. However, there is still a dearth of pertinent data on the relationship between some of the maternal risk factors and newborn 25(OH)D concentrations, for instance, relationships between gestational diabetes and neonatal VitD status. Additional research is required to determine if the same target for 25(OH)D concentrations applies for pregnant women, neonates, and infants.

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.

Sunshine, fertility and racial disparities

This research investigates the effect of sun exposure on fertility, with a special focus on how its effects and consequences for birth outcomes may differ by race. Sun exposure is a key mechanism for obtaining Vitamin D, but this process is inhibited by skin pigmentation. Vitamin D has been linked to male and female fertility and risk of miscarriage, and Vitamin D deficiency is more prevalent among blacks than whites. Using 1989-2004 individual live births data from the Natality Detail Files, county-level, monthly conceptions are estimated as a function of monthly solar insolation, temperature and humidity, as well as month, time and location fixed effects and controls. Insolation has positive, statistically significant effects on fertility for both non-Hispanic blacks and whites, but the effects are stronger and the pattern of effect different for black mothers than white mothers. Poisson estimates from the main model suggest that a 1kWh increase in average daily insolation in the conception month - approximately the difference in sunshine experienced in the typical September vs. October - increases non-Hispanic black conceptions by 1% and non-Hispanic white conceptions by 0.6%. Allowing insolation's effect to differ by maternal characteristic suggests that the racial differences are not being driven by differences in socioeconomic status (SES). Models that allow for more complicated timing of insolation's effect further suggest that insolation pushes black (white) conceptions into the unfavorable (favorable) season of birth. These estimated effects and our decomposition analyses suggest that insolation - and the implied Vitamin D deficiency underlying its effect-helps explain why black conceptions are more likely to display a seasonal pattern that is disadvantageous to birth outcomes.

High prevalence of vitamin D deficiency in pregnant women and its relationship with adverse pregnancy outcomes in Guizhou, China

OBJECTIVE

This study was performed to investigate the prevalence of vitamin D deficiency in pregnant women in Guizhou, China and its correlation with adverse infant and maternal outcomes during the perinatal period.

METHODS

In total, 220 pregnant women who received perinatal care and delivered in the Affiliated Hospital of Guizhou Medical University from November 2014 to April 2015 were enrolled. Each woman's serum vitamin D concentration was tested during early pregnancy, and its correlation with adverse infant and maternal outcomes in the perinatal period was analyzed.

RESULTS

The mean serum vitamin D concentration was 29.5 ± 5.8 nmol/L. More than 90% of pregnant women had vitamin D insufficiency. Additionally, 38.4% of women with vitamin D deficiency and 22.2% with vitamin D inadequacy developed adverse perinatal outcomes. The vitamin D level was negatively correlated with adverse pregnancy outcomes.

CONCLUSION

Vitamin D deficiency is highly prevalent among pregnant women in Guizhou, China. The incidence of adverse perinatal outcomes was far higher in association with vitamin D deficiency than sufficiency. A negative correlation was found between the vitamin D level and the incidence of adverse perinatal outcomes in pregnant women. Therefore, targeted screening and proper supplementation are needed during early pregnancy.

Vitamin D and associated perinatal-neonatal outcomes among extremely low-birth-weight infants

OBJECTIVE

To evaluate vitamin D inadequacy among extremely low-birth-weight (ELBW, <1000 g) infants and the association between circulating vitamin D concentrations and perinatal-neonatal outcomes.

STUDY DESIGN

Prospective cohort study of ELBW infants in the neonatal ICU. Blood was collected within the first 3 days after birth after obtaining informed consent. Circulating 25-hydroxyvitamin D concentrations (25(OH)D) were quantified using liquid chromatography-tandem mass spectroscopy and classified as vitamin D deficient, insufficient, or adequate ( < 20, 20-30, or > 30 ng/mL, respectively). Associations between 25(OH)D and perinatal-neonatal outcomes were determined by multivariable regression, adjusted for covariates that differ in the bivariate analysis.

RESULTS

Of the 60 ELBW infants enrolled, 13 (22%) were vitamin D deficient, 15 (25%) were insufficient, and 32 (53%) were adequate. 25(OH)D levels were positively associated with fetal growth restriction and prolonged rupture of the membranes.

CONCLUSIONS

Vitamin D inadequacy was frequent among ELBW infants. Circulating vitamin D concentrations were significantly associated with perinatal outcomes in this contemporary cohort.

Update of the tolerable upper intake level for vitamin D for infants

Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to revise the tolerable upper intake level (UL) for vitamin D for infants (≤ 1 year) set in 2012. From its literature review, the Panel concluded that the available evidence on daily vitamin D intake and the risk of adverse health outcomes (hypercalciuria, hypercalcaemia, nephrocalcinosis and abnormal growth patterns) cannot be used alone for deriving the UL for infants. The Panel conducted a meta-regression analysis of collected data, to derive a dose-response relationship between daily supplemental intake of vitamin D and mean achieved serum 25(OH)D concentrations. Considering that a serum 25(OH)D concentration of 200 nmol/L or below is unlikely to pose a risk of adverse health outcomes in infants, the Panel estimated the percentage of infants reaching a concentration above this value at different intakes of vitamin D. Based on the overall evidence, the Panel kept the UL of 25 μg/day for infants aged up to 6 months and set a UL of 35 μg/day for infants 6-12 months. The Panel was also asked to advise on the safety of the consumption of infant formulae with an increased maximum vitamin D content of 3 μg/100 kcal (Commission Delegated Regulation (EU) 2016/127 repealing Directive 2006/141/EC in 2020). For infants aged up to 4 months, the intake assessment showed that the use of infant formulae containing vitamin D at 3 μg/100 kcal may lead some infants to receive an intake above the UL of 25 μg/day from formulae alone without considering vitamin D supplemental intake. For infants aged 4-12 months, the 95th percentile of vitamin D intake (high consumers) estimated from formulae and foods fortified or not with vitamin D does not exceed the ULs, without considering vitamin D supplemental intake.

Severe vitamin D deficiency in the first trimester is associated with placental inflammation in high-risk singleton pregnancy

BACKGROUND & AIMS

Vitamin D deficiency during pregnancy is a worldwide epidemic. This study aimed to identify whether vitamin D deficiency in early pregnancy is associated with placental inflammation in high-risk pregnancy.

METHODS

This study comprised 23,396 women who provided serum samples in the first trimester for vitamin D analysis from January 2015 to December 2016. Among them, 2648 women with high-risk pregnancy underwent placental pathologic examination. Women were divided into placental inflammation positive (PIP) and placental inflammation negative (PIN) groups based on placental pathology. Multivariate logistic regression was used to evaluate the relationship between vitamin D levels and placental inflammation.

RESULTS

We found that severe vitamin D deficiency in early pregnancy was associated with placental inflammation. Maternal vitamin D levels were significantly lower in the PIP group than those in the PIN group (P = 0.025). Compared with the highest quartile of vitamin D levels, risk for placental inflammation was significantly higher in women with extremely low vitamin D levels (<5th percentile; P = 0.012). The effect estimate was slightly decreased but still significant (P = 0.027) after adjusting for maternal age, gestational age at birth, birth weight, infant sex, and sample collection season. In addition, compared with the PIN group, the incidences of adverse neonatal outcomes, including sepsis (0.5% vs 2.4%) and fetal intrauterine infection (5.7% vs 15.6%), were significantly higher in the PIP group than that in the PIN group (P < 0.001).

CONCLUSIONS

Severe vitamin D deficiency in the first trimester is a risk factor for placental inflammation in high-risk pregnancy.

Periodontal diseases and adverse pregnancy outcomes: Is there a role for vitamin D?

Studies have shown a relationship between maternal periodontal diseases (PDs) and premature delivery. PDs are commonly encountered oral diseases which cause progressive damage to the periodontal ligament and alveolar bones, leading to loss of teeth and oral disabilities. PDs also adversely affect general health by worsening of cardiovascular and metabolic diseases. Moreover, maternal PDs are thought to be related to increasing the frequency of preterm-birth with low birth weight (PBLBW) in new-borns. Prematurity and immaturity are the leading causes of prenatal and infant mortality and is a major public health problem around the world. Inflamed periodontal tissues generate significantly high levels of proinflammatory cytokines that may have systemic effects on the host mother and the fetus. In addition, the bacteria that cause PDs produce endotoxins which can harm the fetus. Furthermore, studies have shown that microorganisms causing PDs can get access to the bloodstream, invading uterine tissues, to induce PBLBW. Another likely mechanism that connects PDs with adverse pregnancy outcome is maternal vitamin D status. A role of inadequate vitamin D status in the genesis of PDs has been reported. Administration of vitamin D supplementation during pregnancy could reduce the risk of maternal infections and adverse pregnancy outcomes. As maternal PDs are significant risk factors for adverse pregnancy outcome, preventive antenatal care for pregnant women in collaboration with the obstetric and dental professions are required.

Vitamin D: Effects on human reproduction, pregnancy, and fetal well-being

Pregnancy places exceptional demands on vitamin D and calcium availability; thus, their deficiencies during pregnancy threaten the woman and her fetus. Globally, vitamin D and other micronutrient deficiencies are common during pregnancy, especially in developing countries where pregnant women have less access to nutritional supplements. Vitamin D deficiency has been reported to be as high as 40% among pregnant women. As a pregnancy progresses, the requirements for vitamin D increase and thus, can worsen preexisting hypovitaminosis D. Consequently, hypovitaminosis D is increasingly associated with a higher incidence of fetal miscarriage, preeclampsia, gestational diabetes, bacterial vaginosis, and impaired fetal and childhood growth and development. This review explores the recent advances in the understanding of vitamin D and the pivotal role it plays in human reproduction, with an emphasis on pregnancy and its outcomes. Given the seriousness of the issue, there is a pressing need for clinicians to become aware of the risks associated with not identifying and correcting vitamin D deficiency. Identifying and correcting vitamin D deficiency, including safe exposure to sunlight, is particularly relevant for those who seek assistance with fertility issues or prenatal counseling, and those in the beginning of their pregnancy. The data point to a significant protective effects of vitamin D during pregnancy when the 25(OH)D serum level exceeds 30 ng/mL before pregnancy and during the first trimester and, sufficient levels are maintained throughout the pregnancy.

Overview of Nutrients in Human Milk

The WHO recommends exclusive breastfeeding for the first 6 mo of life to promote optimal infant health and development. Understanding the micro- and macronutrient concentrations of human milk and how each nutrient fluctuates with lactational stage, maternal factors, and supplementation is imperative for supporting good breastfeeding practices. Where maternal undernutrition compromises human milk quality, a thorough awareness of the effectiveness of interventions can direct efforts to achieve both maternal and infant nutrient sufficiency. This review of current knowledge covers trends in nutrient concentrations over the course of lactation and describes the influence of maternal intake, status, supplementation, and other factors on human milk concentrations of each nutrient.

Alterations in the vitamin D endocrine system during pregnancy: A longitudinal study of 855 healthy Norwegian women

To ensure optimal calcium accrual in the fetal skeleton, a substantial rise occurs in 1,25-dihydroxyvitamin D (1,25(OH)2D), but is dependent on sufficient 25-hydroxyvitamin (25(OH)D). Large longitudinal studies addressing free 25(OH)D and 1,25(OH)2D during pregnancy are scarce. We aimed to assess levels of and relationship between 25(OH)D, 1,25(OH)2D, vitamin D-binding protein (DBP), parathyroid hormone (PTH), and free 25(OH)D during pregnancy; determinants of vitamin D status; and association between vitamin D indices or PTH and pregnancy outcomes (gestational diabetes mellitus and birthweight). Altogether 855 pregnant Norwegian Caucasian women from Trondheim and Stavanger (latitude 63°N and 58°N) were recruited; 94 were lost to follow-up. The study was originally a randomized controlled trial (2007-2009) with gestational diabetes as primary outcome. Data were collected in second and third trimester. In third trimester, 246 (34%) had vitamin D insufficiency and 52 (7%) deficiency (25(OH)D <50 and <30nmol/L, respectively). During wintertime in third trimester, 61 (47%) from Trondheim and 23 (51%) from Stavanger exhibited vitamin D insufficiency. PTH was elevated in 27 (3.7%). Estimate of change between trimesters was (95% CI): 25(OH)D -1.8 (-2.8 to -0.7) nmol/L, DBP 0.62 (0.57 to 0.66) μmol/L, calculated free 25(OH)D -1.7 (-2.0 to -1.4) pmol/L, PTH 0.81 (0.72 to 0.90) pmol/L, 1,25(OH)2D (sub-analysis) 31.4 (CI 24.7 to 38.2) pmol/L. A decrease in 1,25(OH)2D occurred in 45% of those with vitamin D deficiency, and they also exhibited lower levels than women with adequate vitamin D status. No association of vitamin D indices and PTH with pregnancy outcomes was observed. Women in Trondheim displayed lower 25(OH)D levels, despite minor latitudinal differences. Less than one-fifth adhered to the authorities' vitamin D recommendations. These findings demonstrate that hypovitaminosis D is prevalent among pregnant women living in northern latitudes, especially during the dark season, and there is an unmet need to ensure adequate vitamin D intake.

Postpartum depression and vitamin D: A systematic review

Postpartum depression (PPD) is a prevalent mood disorder estimated to affect 20%-40% of women worldwide after childbirth. In recent studies, the effect of vitamin D on prevention of mood disorders and depression has been investigated, but it is still unclear how vitamin D may affect PPD. The evidence on the relevance between vitamin D deficiency and PPD is inconsistent, and assessment of the recent literature has not previously been carried out. Moreover, there are few clinical studies on PPD and vitamin D supplementation. Five studies have so far assessed the relationship between the levels of vitamin D and PPD. Findings from cohort studies suggest that vitamin-D deficiency is related to the incidence of PPD and vitamin D may play a significant role in the recovery of women with PPD, but it is uncertain whether these actions are the effect of vitamin D on the function of hypothalamic-pituitary-adrenal (HPA) axis, the levels of estradiol, serotonin, pro-inflammatory cytokines, and/or of other mechanisms involved in PPD.

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.

Vitamin D Deficiency in Pregnant Ukrainian Women: Effects of Alcohol Consumption on Vitamin D Status

OBJECTIVE

Heavy alcohol consumption can alter vitamin D status; however, the relationships between alcohol consumption and vitamin D concentrations in pregnant women have not been well studied. The aim of this study was to investigate the vitamin D status in a population of alcohol-exposed (N = 180) and low/unexposed control (N = 179) Ukrainian pregnant women.

METHODS

Women who attended prenatal care facilities in 2 regions of Ukraine (Rivne and Khmelnytsky) for a routine prenatal visit were screened for the study. At the time of enrollment (20.4 ± 7.0 weeks of gestation), blood samples and alcohol consumption data (during a typical week around conception and the most recent 2 weeks) were collected. Vitamin D status was assessed by 25-hydroxyvitamin D [25(OH)D] concentrations.

RESULTS

A high prevalence of suboptimal vitamin D status in pregnant Ukrainian women was observed. Overall, 50.1% and 33.4% of the women were classified as vitamin D deficient [25(OH)D < 20 ng/mL] or insufficient [25(OH)D ≥ 20 ng/mL and ≤30 ng/mL], respectively, based on 2011 Endocrine Society guidelines. Alcohol-exposed women had significantly lower 25(OH)D concentrations than low/unexposed women in Spring (p = 0.006) and Winter (p = 0.022). When vitamin D concentrations were grouped into sunny season (Summer + Fall) compared to not sunny season (Winter + Spring), there was a significant ethanol by season interaction (p = 0.0028), with alcohol-drinking women having lower circulating vitamin D compared to low/unexposed women in seasons of low sun availability.

CONCLUSIONS

These data suggest that when vitamin D concentrations are generally low (e.g., during seasons of low sun availability), alcohol consumption during pregnancy has a negative impact on vitamin D status.

Randomized trial of two doses of vitamin D3 in preterm infants <32 weeks: Dose impact on achieving desired serum 25(OH)D3 in a NICU population

BACKGROUND

Recommendations for vitamin D supplementation for preterm infants span a wide range of doses. Response to vitamin D supplementation and impact on outcomes in preterm infants is not well understood.

OBJECTIVE

Evaluate serum 25(OH)D3 concentration changes after 4 weeks in response to two different doses of vitamin D3 supplementation in a population of premature infants and quantify the impact on NICU outcomes.

DESIGN

32 infants born at 24-32 weeks gestation were prospectively randomized to receive 400 or 800 IU/day vitamin D3 supplementation. Serum 25(OH)D3 levels were measured every 4 weeks. The Wilcoxon signed rank test was used to compare serum levels of 25(OH)D3 at 4 weeks and each subsequent time point. A p-value of <0.05 was considered statistically significant.

RESULTS

Serum 25(OH)D3 levels at birth were 41.9 and 42.9 nmol/l for infants in the 400 IU group and 800 IU group, respectively (p = 0.86). Cord 25(OH)D3 concentrations significantly correlated with gestational age (r = 0.40, p = 0.04). After 4 weeks of D3 supplementation, median 25(OH)D3 levels increased in both groups (84.6vs. 105.3 nmol/l for 400 vs. 800 IU/day respectively, with significantly more improvement in the higher dose (p = 0.048). Infants in the 400 IU group were significantly more likely to have dual energy x-ray absorptiometry (DEXA) bone density measurements <10 percentile (56% vs 16%, p = 0.04).

CONCLUSIONS

Improvement in 25(OH)D3 levels at 4 weeks, bone density, and trends towards improvement in linear growth support consideration of a daily dose of 800 IU of vitamin D for infants <32 weeks cared for in the NICU.

Gestational Diabetes Mellitus, Fetal Growth and Vitamin D

Vitamin D is an important secosteroid hormone in skeletal and non-skeletal systems. Vitamin D has relevance to muscle and immune function, hypertension, diabetes mellitus, cancer, and pregnancy because vitamin D receptors (VDR) are present in many non-skeletal tissues. Vitamin D acts on target tissues via the binding of its active form to VDR. As vitamin D affects not only bone metabolism but also glucose metabolism, vitamin D deficiency may affect the development of gestational diabetes mellitus and fetal growth. Although vitamin D deficiency is prevalent during pregnancy, there are conflicting reports on the effect of vitamin D deficiency on pregnancy complications, such as fetal growth restriction and gestational diabetes. This article reviews published papers on the effects of vitamin D on gestational diabetes and fetal growth.

Serum and tissue 25-OH vitamin D3 concentrations do not predict bone abnormalities and molecular markers of vitamin D metabolism in the hypovitaminosis D kyphotic pig model

The hypovitaminosis D kyphotic pig provides a model to study maternal vitamin D (D) carryover on gross and molecular characteristics of bone abnormalities in offspring. Excess maternal D is proposed to protect offspring under nutritional challenges from developing bone abnormalities. Relationships between D sufficiency parameters and bone abnormalities were characterised. Sows (n 37) were fed diets with 0 (-D), 8·125 (+D) or 43·750 (++D) µg D3/kg throughout gestation and lactation. At weaning (3 weeks) pigs were fed diets with 0 (-D) or 7·0 (+D) µg D3/kg, each with 75 and 95 % (LCaP) or 150 and 120 % (HCaP) of the Ca and P requirements. Pigs were euthanised before colostrum consumption at birth (n 27), 3 weeks (n 27) or after the nursery period (7 weeks, n 71) for tissue analysis. At 7 weeks, differences due to maternal D were detected (P≤0·05) in pig growth, serum parameters and mRNA expression regardless of nursery diet. Prevalence of kyphosis in pigs at 13 weeks was affected by maternal D, but not prevented by only HCaP or +D nursery diets. Increased (P≤0·05) serum 25-OH-D3 concentrations in sows fed +D or ++D diets were not reflected by similar magnitudes of 25-OH-D3 in colostrum, 18-d milk, or serum and tissue concentrations in pigs. The mode of action by which maternal dietary D influences development of skeletal abnormalities warrants further investigation.

The role of vitamin D in pre-eclampsia: a systematic review

BACKGROUND

The etiology of pre-eclampsia (PE) is not yet fully understood, though current literature indicates an upregulation of inflammatory mediators produced by the placenta as a potential causal mechanism. Vitamin D is known to have anti-inflammatory properties and there is evidence of an inverse relationship between dietary calcium intake and the incidence of PE. Evidence of the role of vitamin D status and supplementation in the etiology and prevention of PE is reviewed in this article along with identification of research gaps to inform future studies.

METHODS

We conducted a structured literature search using MEDLINE electronic databases to identify published studies until February 2015. These sources were retrieved, collected, indexed, and assessed for availability of pregnancy-related data on PE and vitamin D.

RESULTS

Several case-control studies and cross-sectional studies have shown an association between vitamin D status and PE, although evidence has been inconsistent. Clinical trials to date have been unable to show an independent effect of vitamin D supplementation in preventing PE.

CONCLUSIONS

The included clinical trials do not show an independent effect of vitamin D supplementation in preventing PE; however, issues with dose, timing, and duration of supplementation have not been completely addressed.

Changes in plasma concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D during pregnancy: a Brazilian cohort

PURPOSE

To characterize the physiological changes in 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)₂D] throughout pregnancy.

METHODS

Prospective cohort of 229 apparently healthy pregnant women followed at 5th-13th, 20th-26th, and 30th-36th gestational weeks. 25(OH)D and 1,25(OH)₂D concentrations were measured by LC-MS/MS. Statistical analyses included longitudinal linear mixed-effects models adjusted for parity, season, education, self-reported skin color, and pre-pregnancy BMI. Vitamin D status was defined based on 25(OH)D concentrations according to the Endocrine Society Practice Guideline and Institute of Medicine (IOM) for adults.

RESULTS

The prevalence of 25(OH)D <75 nmol/L was 70.4, 41.0, and 33.9%; the prevalence of 25(OH)D <50 nmol/L was 16.1, 11.2, and 10.2%; and the prevalence of 25(OH)D <30 nmol/L was 2, 0, and 0.6%, at the first, second, and third trimesters, respectively. Unadjusted analysis showed an increase in 25(OH)D (β = 0.869; 95% CI 0.723-1.014; P < 0.001) and 1,25(OH)₂D (β = 3.878; 95% CI 3.136-4.620; P < 0.001) throughout pregnancy. Multiple adjusted analyses showed that women who started the study in winter (P < 0.001), spring (P < 0.001), or autumn (P = 0.028) presented a longitudinal increase in 25(OH)D concentrations, while women that started during summer did not. Increase of 1,25(OH)₂D concentrations over time in women with insufficient vitamin D (50-75 nmol/L) at baseline was higher compared to women with sufficient vitamin D (≥75 nmol/L) (P = 0.006).

CONCLUSIONS

The prevalence of vitamin D inadequacy varied significantly according to the adopted criteria. There was a seasonal variation of 25(OH)D during pregnancy. The women with insufficient vitamin D status present greater longitudinal increases in the concentrations of 1,25(OH)₂D in comparison to women with sufficiency.

Reduced fetal vitamin D status by maternal undernutrition during discrete gestational windows in sheep

Placental transport of vitamin D and other nutrients (e.g. amino acids, fats and glucose) to the fetus is sensitive to maternal and fetal nutritional cues. We studied the effect of maternal calorific restriction on fetal vitamin D status and the placental expression of genes for nutrient transport [aromatic T-type amino acid transporter-1 (TAT-1); triglyceride hydrolase/lipoprotein uptake facilitator lipoprotein lipase (LPL)] and vitamin D homeostasis [CYP27B1; vitamin D receptor (VDR)], and their association with markers of fetal cardiovascular function and skeletal muscle growth. Pregnant sheep received 100% total metabolizable energy (ME) requirements (control), 40% total ME requirements peri-implantation [PI40, 1-31 days of gestation (dGA)] or 50% total ME requirements in late gestation (L, 104-127 dGA). Fetal, but not maternal, plasma 25-hydroxy-vitamin D (25OHD) concentration was lower in PI40 and L maternal undernutrition groups (P<0.01) compared with the control group at 0.86 gestation. PI40 group placental CYP27B1 messenger RNA (mRNA) levels were increased (P<0.05) compared with the control group. Across all groups, higher fetal plasma 25OHD concentration was associated with higher skeletal muscle myofibre and capillary density (P<0.05). In the placenta, higher VDR mRNA levels were associated with higher TAT-1 (P<0.05) and LPL (P<0.01) mRNA levels. In the PI40 maternal undernutrition group only, reduced fetal plasma 25OHD concentration may be mediated in part by altered placental CYP27B1. The association between placental mRNA levels of VDR and nutrient transport genes suggests a way in which the placenta may integrate nutritional cues in the face of maternal dietary challenges and alter fetal physiology.

Maternal vitamin D insufficiency and risk of adverse pregnancy and birth outcomes: A systematic review and meta-analysis of longitudinal studies

BACKGROUND

Three previous reviews on the association of vitamin D insufficiency in pregnancy with preterm birth (PTB) and stillbirth were limited in scope and deemed inconclusive. With important new evidence accumulating, there is the need to update the previous estimates and assess evidence on other clinically important outcomes such as spontaneous abortion and Apgar score. We conducted a systematic review and meta-analysis to evaluate the quality and strength of the available evidence on the relations between vitamin D nutritional status, and pregnancy and birth outcomes.

METHODS

PubMed and Scopus databases were searched from their inception to June, 2015 with no language restrictions imposed. Eighteen longitudinal studies satisfied the inclusion criteria. Random effects model was applied in computing the summary effect estimates and their corresponding 95% confidence intervals.

RESULTS

Serum 25(OH)D levels <75 nmol/l was associated with 83% (95% CI: 1.23, 2.74) and 13% (95% CI: 0.94, 1.36) increased risk of PTB measured at <32-34 weeks and <35-37 weeks, respectively. An inverse dose-response relation was observed for both PTB outcome. Serum 25(OH)D levels <75 nmol/l was also associated with 11% increased risk of spontaneous PTB (<35-37 weeks; RR = 1.11; 95% CI: 0.75, 1.65) with a dose-response relation also noted. Vitamin D insufficiency was not associated with risk of spontaneous abortion and stillbirth (RR of 1.04 [95% CI: 0.95, 1.13] and 1.02 [95% CI: 0.96, 1.09], respectively), as well as short gestational length (ES = -0.24, 95% CI: -0.69, 0.22), and low Apgar score.

CONCLUSIONS

We found vitamin D insufficiency to be associated with risk of PTB. Regarding spontaneous abortion and stillbirth, the available evidence suggest no association with low vitamin D levels. The evidence on vitamin D nutrition and Apgar score is conflicting and controversial. Overall, the experimental evidence uncovered was small and weak. Hence, the benefits of vitamin D supplementation during pregnancy should be further evaluated through rigorous intervention studies.

Can Getting Enough Vitamin D during Pregnancy Reduce the Risk of Getting Asthma in Childhood?

The worldwide increase in asthma prevalence during the last decades and the re-emergence of vitamin D deficiency in many populations hinted toward an underlying association between these two conditions. Since asthma is presented with high incidence in childhood and neonatal vitamin D stores depend on maternal vitamin levels, a possible programming effect of maternal vitamin D status during gestation was suggested. Observational and longitudinal studies on this subject led to inconclusive results with glimmer of positivity. In the randomized controlled clinical trials (RCTs) that followed, increased doses of vitamin D were tested in pregnant women being at high risk of having an asthmatic child. Although, the results of RCTs showed a potential association with asthma-related phenotypes rather than asthma per se, the low toxicity of vitamin D supplements make it tempting to speculate that pregnant women at a high risk of obtaining a child with asthma may be benefited, especially if they are vitamin D deficient.

Daily Cholecalciferol Supplementation during Pregnancy Alters Markers of Regulatory Immunity, Inflammation, and Clinical Outcomes in a Randomized Controlled Trial

BACKGROUND

Vitamin D deficiency is widespread in pregnancy and has been associated with adverse health conditions in mothers and infants. Vitamin D supplementation in pregnancy may support the maintenance of pregnancy by its effects on innate and adaptive immunity.

OBJECTIVE

We assessed the effects of vitamin D supplementation during pregnancy on vitamin D status and markers of immune function associated with adverse pregnancy outcomes.

METHODS

We conducted a randomized, controlled, double-blind intervention of 2 doses of cholecalciferol (400 and 2000 IU/d) from <20 wk to delivery in 57 pregnant women. Vitamin D status, regulatory and inflammatory T cells, markers of innate immunity and systemic inflammation, and clinical outcomes including maternal blood pressure and birth weight were assessed at 26 and 36 wk of pregnancy.

RESULTS

Supplementation with 2000 IU/d vitamin D had a greater effect on the change in vitamin D status over pregnancy (P < 0.0001) and the final value at 36 wk (P < 0.0001) than 400 IU/d, increasing serum 25-hydroxyvitamin D from 81.1 nmol/L at baseline to 116 nmol/L at 36 wk and from 69.6 nmol/L at baseline to 85.6 nmol/L at 36 wk, respectively. The 2000-IU/d group had 36% more interleukin-10⁺ regulatory CD4⁺ T cells at 36 wk than did the 400-IU/d group (P < 0.007). The daily intake of 2000 compared with 400 IU/d tended to dampen the pregnancy-related increase in diastolic blood pressure by 1.3-fold (P = 0.06) and increase birth weight by 8.6% (P = 0.06), but these differences were not statistically significant.

CONCLUSIONS

Supplementation with 2000 IU/d is more effective at increasing vitamin D status in pregnant women than 400 IU/d and is associated with increased regulatory T cell immunity that may prevent adverse outcomes caused by excess inflammation. This trial was registered at clinicaltrials.gov as NCT01417351.

Effects of maternal genetic polymorphisms in vitamin D-binding protein and serum 25-hydroxyvitamin D concentration on infant birth weight

OBJECTIVE

Vitamin D deficiency is a common problem during pregnancy and might contribute to adverse birth outcomes. Vitamin D-binding protein plays a key role in regulating vitamin D metabolism. We investigated whether maternal genetic variation in GC, the gene encoding vitamin-D binding protein, modulates the relationship between 25-hydroxyvitamin D [25(OH)D] levels and infant birth weight.

METHODS

We measured 25(OH)D concentrations in maternal and umbilical cord blood from 356 pregnant women and their infants by liquid chromatography tandem mass spectrometry. We extracted DNA from the maternal blood for genotyping GC single-nucleotide polymorphisms (SNPs).

RESULTS

The 25(OH)D concentrations were significantly higher in the maternal blood than in the cord blood, although the concentrations from each source were positively correlated with one another among individuals. Maternal GC SNPs rs12512631 and rs7041 were not significantly associated with infant birth weight. On the other hand, the GC SNPs rs12512631 and rs7041 significantly modified the relationships between the maternal and cord-blood concentrations of 25(OH)D and birth weight. Low 25(OH)D levels in the maternal and cord blood were significantly associated with decreased birth weight among infants born to mothers carrying the rs12512631 'C' allele but not in those born to mothers homozygous for the 'T' allele (P-interaction = 0.043 and 0.0008 for the maternal and cord blood, respectively). Low 25(OH)D levels in the cord blood were significantly associated with decreased birth weight only among infants born to mothers carrying the rs7041 'G' allele (P-interaction = 0.009).

CONCLUSIONS

Our findings suggest that the interaction between 25(OH)D status and some maternal GC variants influence the birth weight of infants.

Maternal dietary vitamin D carry-over alters offspring growth, skeletal mineralisation and tissue mRNA expressions of genes related to vitamin D, calcium and phosphorus homoeostasis in swine

Maternal dietary vitamin D carry-over effects were assessed in young pigs to characterise skeletal abnormalities in a diet-induced model of kyphosis. Bone abnormalities were previously induced and bone mineral density (BMD) reduced in offspring from sows fed diets with inadequate vitamin D3. In a nested design, pigs from sows (n 23) fed diets with 0 (-D), 8·125 (+D) or 43·750 (++D) µg D3/kg from breeding through lactation were weaned and, within litter, fed nursery diets arranged as a 2×2 factorial design with 0 (-D) or 7·0 (+D) µg D3/kg, each with 95 % (95P) or 120 % (120P) of P requirements. Selected pigs were euthanised before colostrum consumption at birth (0 weeks, n 23), weaning (3 weeks, n 22) and after a growth period (8 weeks, n 185) for BMD, bone mechanical tests and tissue mRNA analysis. Pigs produced by +D or ++D sows had increased gain at 3 weeks (P<0·05), and at 8 weeks had increased BMD and improved femur mechanical properties. However, responses to nursery diets depended on maternal diets (P<0·05). Relative mRNA expressions of genes revealed a maternal dietary influence at birth in bone osteocalcin and at weaning in kidney 24-hydroxylase (P<0·05). Nursery treatments affected mRNA expressions at 8 weeks. Detection of a maternal and nursery diet interaction (P<0·05) provided insights into the long-term effects of maternal nutritional inputs. Characterising early stages of bone abnormalities provided inferences for humans and animals about maternal dietary influence on offspring skeletal health.

Perinatal vitamin D levels are not associated with later risk of developing pediatric-onset inflammatory bowel disease: a Danish case-cohort study

Objective Basic and epidemiologic studies on inflammatory bowel disease (IBD) have suggested an association between vitamin D and IBD risk. Though, the literature on IBD - especially pediatric-onset IBD - and vitamin D is still in its cradle. We therefore wanted to examine if levels of 25(OH)D at birth were associated with increased risk of developing pediatric-onset IBD. Material and methods A case-cohort study composed of cases diagnosed with Crohn's disease, ulcerative colitis or indeterminate/unclassified colitis and healthy controls. Cases and controls were matched on date of birth and were born in the period 1981-2004. Cases were diagnosed before the age of 18 years. The concentration of 25(OH)D was assessed from neonatal dried blood spots using a highly sensitive liquid chromatography tandem mass spectrometry. Odds ratios (OR) were calculated using conditional logistic regression and two-way ANOVA were used to test for season and birth year 25(OH)D variations. A total of 384 matched pairs were included in the statistical analyses. Results No significant association were found between levels of 25(OH)D and IBD risk in the adjusted model (OR [95% CI] (per 25 nmol/L increase), 1.12 [0.88; 1.42], p = 0.35). 25(OH)D levels were found to fluctuate significantly with season (p < 0.001) and year (p < 0.001). Median/Q1-Q3 values for 25(OH)D were 27.1/16.5-39.5 nmol/L for cases and 25.7/16.1-39.4 nmol/L for controls. Conclusion Our study do not suggest that a window of vulnerability exist around time of birth in regards to 25(OH)D levels and later pediatric-onset IBD risk.

Impact of a Vitamin D Protocol in Pregnancy at an Urban Women’s Health Clinic

Background: Adequate vitamin D levels are important during pregnancy for maternal and fetal health. The prevalence of vitamin D deficiency and appropriate treatment during pregnancy are not well documented. Objectives: This study aims to identify the prevalence of vitamin D deficiency in pregnant women and analyze the impact of a vitamin D protocol on achieving sufficient vitamin D levels. Methods: A retrospective chart review was conducted among 200 women who received prenatal care between April 1, 2011, and December 1, 2012 (preprotocol) and July 1, 2013, and June 30, 2014 (postprotocol). In each sample period, 100 women were included. Women were included if they had 2 vitamin D levels drawn during pregnancy. Maternal age, ethnicity, vitamin D levels, gestational age at each level, and the status of vitamin D supplement were controlled for. Results: Women in the preprotocol group achieving sufficiency (25[OH]D ≥ 30 ng/mL) increased from 43% to 60%. In the postprotocol group, sufficiency increased from 19% to 69%. Adherence to the protocol dose was highest in women who were initially deficient (25[OH]D ≤ 20 ng/mL), and correlation between adherence to the protocol dose and achievement of sufficiency was also highest in the group of women who were initially deficient. Conclusions: Vitamin D deficiency was prevalent (25% total) in this population. Implementation of a clinic-wide protocol for vitamin D supplementation during pregnancy resulted in a nonsignificant increase in the percentage of women achieving vitamin D sufficiency.