Vitamin D supplementation during pregnancy: an overview

Dietary management of gestational diabetes: A review

Gestational diabetes mellitus (GDM) is a common condition in pregnant women that can affect the health of both the mother and the fetus. A healthy diet reduces the risk of GDM, while on the contrary, an unhealthy diet can increase the risk of developing GDM. Dietary interventions remain an important way to control GDM at this time. However, real-life diets are complex and varied, and the effect of these diets on gestational diabetes is unknown. This article summarizes research related to dietary control of GDM. Hopefully, this will help with dietary interventions for people with GDM.

Low Vitamin D Concentration Is Associated with Increased Depression Risk in Adults 20-44 Years Old, an NHANES 2007-2018 Data Analysis with a Focus on Perinatal and Breastfeeding Status

The objective was to investigate associations of serum vitamin D concentration with depressive symptoms and assess the impact that vitamin D concentration has on the occurrence of depressive symptoms in 20-44-year-old pregnant women, postpartum women, non-pp women (non-pregnant/postpartum women), and men, including a separate subgroup analysis of postpartum breastfeeding and non-breastfeeding women. The study populations were selected from the 2007-2018 NHANES public data. Subjective interview data and objective laboratory data including depressive symptoms, serum vitamin D concentration, nutrient intake, and demographic information were utilized. Two diet patterns were created using principal component analysis, and a Bayesian multinomial model was fit to predict the depression outcomes for each subpopulation. The estimates for the log vitamin D slope parameter were negative for all cohorts; as vitamin D increased, the probability of having no depression increased, while the probability of depression decreased. The pregnant cohort had the steepest vitamin D slope, followed by postpartum women, then non-pp women and men. Higher vitamin D concentration had more impact on decreasing depression risk in pregnant and postpartum women compared to non-pp women and men. Among postpartum women, higher vitamin D concentration had a greater influence on decreasing breastfeeding women's depression risk than non-breastfeeding women.

Altered liver metabolism post-wean abolishes efficacy of vitamin D for breast cancer prevention in a mouse model

Young women have increased risk of vitamin D deficiency, which may increase breast cancer incidence. Here, we assessed the anti-cancer efficacy of vitamin D in mouse models of young-onset breast cancer. In never-pregnant mice, vitamin D supplementation increased serum 25(OH)D and hepatic 1,25(OH)2D3, reduced tumor size, and associated with anti-tumor immunity. These anti-tumor effects were not replicated in a mouse model of postpartum breast cancer, where hepatic metabolism of vitamin D was suppressed post-wean, which resulted in deficient serum 25(OH)D and reduced hepatic 1,25(OH)2D3. Treatment with active 1,25(OH)2D3 induced hypercalcemia exclusively in post-wean mice, highlighting metabolic imbalance post-wean. RNAseq revealed suppressed CYP450 expression postpartum. In sum, we provide evidence that vitamin D anti-tumor activity is mediated through immunomodulatory mechanisms and is ineffective in the post-wean window due to altered hepatic metabolism. These findings have implications for suppressed xenobiotic metabolism in postpartum women beyond vitamin D.

Consequences of Maternal Vitamin D Deficiency on Newborn Health

BACKGROUND AND OBJECTIVES

Maternal-fetal gestational pathology is one of the biggest challenges in the field of health at this moment. The current study is designed to determine the effects of vitamin D on pregnancy, starting with the idea that impairment of vitamin D status is thought to be correlated with impairment of the newborn's health.

MATERIALS AND METHODS

In this retrospective study, we tried to establish the link between vitamin D deficiency and maternal characteristics and also how it impacted the clinical status of the newborn. We analyzed a group of 260 patients: 130 pregnant women and 130 newborns, in whom vitamin D status was detected using the serum levels of 25-hydroxyvitamin D (25-(OH)D).

RESULTS

The results showed that vitamin D deficiency has a high incidence among pregnant women, as was presented in many important international studies. Our study also showed a positive, direct correlation between the mother's and newborn's vitamin D status.

CONCLUSIONS

Taking into consideration that vitamin D deficiency has been correlated with many complications, both in maternal and newborn health, a serum level determination of 25-(OH)D is necessary in the first trimester of pregnancy, and after that, adequate supplementation is necessary in order to prevent any negative effects.

A Study of Vitamin D Status and Its Influencing Factors among Pregnant Women in Szeged, Hungary: A Secondary Outcome of a Case-Control Study

Adequate vitamin D (VD) intake during pregnancy is needed for fetal development and maternal health maintenance. However, while there is no doubt regarding its importance, there is not a unified recommendation regarding adequate intake. The main aim of our study was to measure the VD serum level of studied women, together with its potential influencing factors: demographic (i.e., age, level of education, relationship status and type of residence), conception and pregnancy related factors. Results are based on secondary data analyses of a retrospective case-control study of 100 preterm and 200 term pregnancies, where case and control groups were analyzed together. Data collection was based on a self-administered questionnaire, health documentation, and maternal serum VD laboratory tests. VD intake was evaluated by diet and dietary supplement consumption. According to our results, 68.1% of women took some kind of prenatal vitamin, and only 25.9% of them knew about its VD content. Only 12.1% of included women reached the optimal, 75 nmol/L serum VD level. Higher maternal serum levels were associated with early pregnancy care visits (p = 0.001), assisted reproductive therapy (p = 0.028) and advice from gynecologists (p = 0.049). A correlation was found between VD intake and serum levels (p < 0.001). Despite the compulsory pregnancy counselling in Hungary, health consciousness, VD intake and serum levels remain below the recommendations. The role of healthcare professionals is crucial during pregnancy regarding micronutrients intake and the appropriate supplementation dose.

Between Dysbiosis, Maternal Immune Activation and Autism: Is There a Common Pathway?

Autism spectrum disorder (ASD) is a neuropsychiatric condition characterized by impaired social interactions and repetitive stereotyped behaviors. Growing evidence highlights an important role of the gut-brain-microbiome axis in the pathogenesis of ASD. Research indicates an abnormal composition of the gut microbiome and the potential involvement of bacterial molecules in neuroinflammation and brain development disruptions. Concurrently, attention is directed towards the role of short-chain fatty acids (SCFAs) and impaired intestinal tightness. This comprehensive review emphasizes the potential impact of maternal gut microbiota changes on the development of autism in children, especially considering maternal immune activation (MIA). The following paper evaluates the impact of the birth route on the colonization of the child with bacteria in the first weeks of life. Furthermore, it explores the role of pro-inflammatory cytokines, such as IL-6 and IL-17a and mother's obesity as potentially environmental factors of ASD. The purpose of this review is to advance our understanding of ASD pathogenesis, while also searching for the positive implications of the latest therapies, such as probiotics, prebiotics or fecal microbiota transplantation, targeting the gut microbiota and reducing inflammation. This review aims to provide valuable insights that could instruct future studies and treatments for individuals affected by ASD.

The Effect of Vitamin D Supplementation in Pregnant Women with Overweight and Obesity: A Randomised Controlled Trial

The impact of vitamin D supplementation on 25-hydroxyvitamin D (25OHD) levels, metabolic status, and pregnancy outcomes in pregnant women with overweight and obesity (OW/OB) is uncertain. This study aimed to examine whether administrating 800 IU of vitamin D3 orally would improve maternal serum 25OHD levels, lipid profile, and pregnancy outcomes compared to 400 IU. This was a two-arm, parallel, non-blinded randomised controlled trial involving 274 pregnant women recruited from KK Women's and Children's Hospital, with a body mass index of ≥25 kg/m2 within 16 weeks gestation. The participants were randomly assigned to receive 800 IU/day (intervention group) or 400 IU/day (control group) of oral vitamin D3 supplements. The primary outcomes were maternal serum 25OHD and lipid levels at 24-28 weeks gestation. The secondary outcomes included maternal and birth outcomes. Compared with controls (n = 119), the intervention group (n = 112) exhibited higher 25OHD levels at 24-28 weeks gestation (adjusted mean difference 6.52 nmol/L; 95% confidence interval 2.74, 10.31). More women in the intervention group achieved sufficient 25OHD levels (77.7% vs. 55.5%; p < 0.001). No differences were observed in lipid profiles or maternal or birth outcomes between the groups. An additional 400 IU of oral vitamin D3 supplementation increased serum 25OHD levels but did not impact lipid profiles or pregnancy outcomes.

Linking Prenatal Environmental Exposures to Lifetime Health with Epigenome-Wide Association Studies: State-of-the-Science Review and Future Recommendations

BACKGROUND

The prenatal environment influences lifetime health; epigenetic mechanisms likely predominate. In 2016, the first international consortium paper on cigarette smoking during pregnancy and offspring DNA methylation identified extensive, reproducible exposure signals. This finding raised expectations for epigenome-wide association studies (EWAS) of other exposures.

OBJECTIVE

We review the current state-of-the-science for DNA methylation associations across prenatal exposures in humans and provide future recommendations.

METHODS

We reviewed 134 prenatal environmental EWAS of DNA methylation in newborns, focusing on 51 epidemiological studies with meta-analysis or replication testing. Exposures spanned cigarette smoking, alcohol consumption, air pollution, dietary factors, psychosocial stress, metals, other chemicals, and other exogenous factors. Of the reproducible DNA methylation signatures, we examined implementation as exposure biomarkers.

RESULTS

Only 19 (14%) of these prenatal EWAS were conducted in cohorts of 1,000 or more individuals, reflecting the still early stage of the field. To date, the largest perinatal EWAS sample size was 6,685 participants. For comparison, the most recent genome-wide association study for birth weight included more than 300,000 individuals. Replication, at some level, was successful with exposures to cigarette smoking, folate, dietary glycemic index, particulate matter with aerodynamic diameter < 10 μ m and < 2.5 μ m , nitrogen dioxide, mercury, cadmium, arsenic, electronic waste, PFAS, and DDT. Reproducible effects of a more limited set of prenatal exposures (smoking, folate) enabled robust methylation biomarker creation.

DISCUSSION

Current evidence demonstrates the scientific premise for reproducible DNA methylation exposure signatures. Better powered EWAS could identify signatures across many exposures and enable comprehensive biomarker development. Whether methylation biomarkers of exposures themselves cause health effects remains unclear. We expect that larger EWAS with enhanced coverage of epigenome and exposome, along with improved single-cell technologies and evolving methods for integrative multi-omics analyses and causal inference, will expand mechanistic understanding of causal links between environmental exposures, the epigenome, and health outcomes throughout the life course. https://doi.org/10.1289/EHP12956.

Maternal B-vitamin and vitamin D status before, during, and after pregnancy and the influence of supplementation preconception and during pregnancy: Prespecified secondary analysis of the NiPPeR double-blind randomized controlled trial

BACKGROUND

Maternal vitamin status preconception and during pregnancy has important consequences for pregnancy outcome and offspring development. Changes in vitamin status from preconception through early and late pregnancy and postpartum have been inferred from cross-sectional data, but longitudinal data on vitamin status from preconception throughout pregnancy and postdelivery are sparse. As such, the influence of vitamin supplementation on vitamin status during pregnancy remains uncertain. This study presents one prespecified outcome from the randomized controlled NiPPeR trial, aiming to identify longitudinal patterns of maternal vitamin status from preconception, through early and late pregnancy, to 6 months postdelivery, and determine the influence of vitamin supplementation.

METHODS AND FINDINGS

In the NiPPeR trial, 1,729 women (from the United Kingdom, Singapore, and New Zealand) aged 18 to 38 years and planning conception were randomized to receive a standard vitamin supplement (control; n = 859) or an enhanced vitamin supplement (intervention; n = 870) starting in preconception and continued throughout pregnancy, with blinding of participants and research staff. Supplement components common to both treatment groups included folic acid, β-carotene, iron, calcium, and iodine; components additionally included in the intervention group were riboflavin, vitamins B6, B12, and D (in amounts available in over-the-counter supplements), myo-inositol, probiotics, and zinc. The primary outcome of the study was glucose tolerance at 28 weeks' gestation, measured by oral glucose tolerance test. The secondary outcome reported in this study was the reduction in maternal micronutrient insufficiency in riboflavin, vitamin B6, vitamin B12, and vitamin D, before and during pregnancy. We measured maternal plasma concentrations of B-vitamins, vitamin D, and markers of insufficiency/deficiency (homocysteine, hydroxykynurenine-ratio, methylmalonic acid) at recruitment, 1 month after commencing intervention preconception, in early pregnancy (7 to 11 weeks' gestation) and late pregnancy (around 28 weeks' gestation), and postdelivery (6 months after supplement discontinuation). We derived standard deviation scores (SDS) to characterize longitudinal changes among participants in the control group and measured differences between the 2 groups. At recruitment, the proportion of patients with marginal or low plasma status was 29.2% for folate (<13.6 nmol/L), 7.5% and 82.0% for riboflavin (<5 nmol/L and ≤26.5 nmol/L, respectively), 9.1% for vitamin B12 (<221 pmol/L), and 48.7% for vitamin D (<50 nmol/L); these proportions were balanced between the groups. Over 90% of all participants had low or marginal status for one or more of these vitamins at recruitment. Among participants in the control group, plasma concentrations of riboflavin declined through early and late pregnancy, whereas concentrations of 25-hydroxyvitamin D were unchanged in early pregnancy, and concentrations of vitamin B6 and B12 declined throughout pregnancy, becoming >1 SDS lower than baseline by 28 weeks gestation. In the control group, 54.2% of participants developed low late-pregnancy vitamin B6 concentrations (pyridoxal 5-phosphate <20 nmol/L). After 1 month of supplementation, plasma concentrations of supplement components were substantially higher among participants in the intervention group than those in the control group: riboflavin by 0.77 SDS (95% CI 0.68 to 0.87, p < 0.0001), vitamin B6 by 1.07 SDS (0.99 to 1.14, p < 0.0001), vitamin B12 by 0.55 SDS (0.46 to 0.64, p < 0.0001), and vitamin D by 0.51 SDS (0.43 to 0.60, p < 0.0001), with higher levels in the intervention group maintained during pregnancy. Markers of vitamin insufficiency/deficiency were reduced in the intervention group, and the proportion of participants with vitamin D insufficiency (<50 nmol/L) during late pregnancy was lower in the intervention group (35.1% versus 8.5%; p < 0.0001). Plasma vitamin B12 remained higher in the intervention group than in the control group 6 months postdelivery (by 0.30 SDS (0.14, 0.46), p = 0.0003). The main limitation is that generalizability to the global population is limited by the high-resource settings and the lack of African and Amerindian women in particular.

CONCLUSIONS

Over 90% of the trial participants had marginal or low concentrations of one or more of folate, riboflavin, vitamin B12, or vitamin D during preconception, and many developed markers of vitamin B6 deficiency in late pregnancy. Preconception/pregnancy supplementation in amounts available in over-the-counter supplements substantially reduces the prevalence of vitamin deficiency and depletion markers before and during pregnancy, with higher maternal plasma vitamin B12 maintained during the recommended lactational period.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02509988; U1111-1171-8056.

Minipuberty in Sons of Women with Low Vitamin D Status during Pregnancy

Minipuberty is a transient phase of reproductive axis activation during the first several months of life, playing an important role in the development of reproductive organs in boys. Low 25-hydroxyvitamin D levels during pregnancy are associated with an increased risk of neonatal complications. An inadequate gestational vitamin D status is hypothesized to affect the postnatal activation of the hypothalamic-pituitary-gonadal axis. The purpose of our study was to assess whether a low vitamin D status during pregnancy determines the course of minipuberty in boys. The study included three groups of male infants born to women with different vitamin D statuses: sons of women with vitamin D deficiency (group 1), sons of women with vitamin D insufficiency (group 2), and male offspring of females with normal 25-hydroxyvitamin D levels (group 3 (the reference group)). Concentrations of testosterone, androstenedione, dehydroepiandrosterone sulfate, estradiol, progesterone, and 17-hydroxyprogesterone in saliva, as well as concentrations of gonadotropins in urine, were assayed monthly from postnatal months 1 to 6, and once every 2 months in the second half of the first year of life. Additionally, at each visit, penile length and testicular volume were assessed. Concentrations of testosterone, FSH, and LH, as well as penile length and testicular volume, were greater in group 1 than in groups 2 and 3. In turn, group 2 was characterized by higher FSH levels and a greater testicular volume than group 3. Peak concentrations of LH and testosterone were observed earlier in group 1 than in the remaining groups. The obtained results suggest that a low vitamin D status during pregnancy may have a stimulatory impact on reproductive axis activity and on the early postnatal development of male genital organs, correlating with the severity of hypovitaminosis D.

Vitamin D Intake and Serum Levels in Pregnant and Postpartum Women

Maternal vitamin D deficiency, which is highly prevalent in pregnant women in Europe, is linked to adverse health effects for both the mother and child. The objective was to assess vitamin D status in pregnant women by evaluating their dietary and supplemental vitamin D intake, serum vitamin D levels, parathyroid hormone levels, and lifestyle factors. This cross-sectional study, with a total of 735 participants (145 pregnant and 590 up to the seventh day postpartum), took place in Latvia. Blood samples, a food frequency questionnaire, and medical documentation were used for data collection. The median serum vitamin D concentration was 34.0 ng/mL, with pregnant women having higher levels (42.9 ng/mL) than postpartum women (31.8 ng/mL). There was no association between vitamin D serum concentration and dietary intake of vitamin D (p > 0.05), whereas there was a significant correlation with use of vitamin D supplements (r = 0.41; p < 0.001 in pregnant women and r = 0.35; p < 0.001 in postpartum women). This study demonstrated that a minority of pregnant women (21.9%) had optimal serum vitamin D concentration (>45 ng/mL), and diet had no significant impact on vitamin D levels. Thus, our proposed recommendation for vitamin D intake during pregnancy was 63 mcg (2500 IU) year-round for optimal levels in pregnant women in Northeastern Europe.

Clinical Toxicology of Vitamin D in Pediatrics: A Review and Case Reports

Intoxication of vitamin D is not a common case in pediatrics. Vitamin D supplements are sold as OTC drugs; however, there is a lack of public education about the permissible limits of vitamin D intake which may lead to vitamin D toxicity (VDT). This review aims to give insights to readers or practitioners about the clinical toxicology of vitamin D in pediatrics, which includes the mechanism of VDT, case reports, and the management of vitamin D poisoning. VDT refers to serum 25(OH)D levels, particularly when the level exceeds 100 ng/mL (250 nmol/L) or is defined as hypervitaminosis D. Hypercalcemia is a common condition of vitamin D toxicity. Vitamin D and its metabolites in moderate levels can induce hypercalcemia, as indicated by the elevation of osteoclastic bone resorption, the presence of calcium in renal tubules, intestinal calcium intake (through increased production of calcium-binding protein in enterocytes), and the decrease of parathyroid hormone synthesis. VDT in pediatrics can be managed by discontinuing vitamin D intake; using activated charcoal, furosemide, prednisone, and calcitonin; rehydration using intravenous sodium chloride 0.9%; and dextrose fluid therapy. It is important for parents to be more careful when providing vitamin D to their children.

Preventing and Treating Torsades de Pointes in the Mother, Fetus and Newborn in the Highest Risk Pregnancies with Inherited Arrhythmia Syndromes

The number of women of childbearing age who have been diagnosed in childhood with ion channelopathy and effectively treated using beta blockers, cardiac sympathectomy, and life-saving cardiac pacemakers/defibrillators is increasing. Since many of these diseases are inherited as autosomal dominant, offspring have about a 50% risk of having the disease, though many will be only mildly impacted during fetal life. However, highly complex delivery room preparation is increasingly needed in pregnancies with inherited arrhythmia syndromes (IASs). However, specific Doppler techniques show meanwhile a better understanding of fetal electrophysiology. The advent of fetal magnetocardiography (FMCG) now allows the detection of fetal Torsades de Pointes (TdP) ventricular tachycardia and other LQT-associated arrhythmias (QTc prolongation, functional second AV block, T-wave alternans, sinus bradycardia, late-coupled ventricular ectopy and monomorphic VT) in susceptible fetuses during the second and third trimester. These types of arrhythmias can be due to either de novo or familial Long QT Syndrome (LQTS), Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT), or other IAS. It is imperative that the multiple specialists involved in the antenatal, peripartum, and neonatal care of these women and their fetuses/infants have the optimal knowledge, training and equipment in order to care for these highly specialized pregnancies and deliveries. In this review, we outline the steps to recognize symptomatic LQTS in either the mother, fetus or both, along with suggestions for evaluation and management of the pregnancy, delivery, or post-partum period impacted by LQTS.

Effects of Climate, Sun Exposure, and Dietary Intake on Vitamin D Concentrations in Pregnant Women: A Population-Based Study

BACKGROUND

Vitamin D deficiency (VDD) is a global micronutrient issue that commonly occurs in pregnant women, leading to adverse health outcomes. We examined the role of sunlight-related factors and dietary vitamin D intake on vitamin D concentrations among pregnant women in different climate zones.

METHODS

We conducted a nationwide cross-sectional survey in Taiwan between June 2017 and February 2019. The data of 1502 pregnant women were collected, including sociodemographic information and characteristics related to pregnancy, diet, and sun exposure. Serum 25-hydroxyvitamin D concentrations were measured, and VDD was assessed as a concentration of less than 20 ng/mL. Logistic regression analyses were used to explore the factors associated with VDD. Furthermore, the area under the receiver operating characteristic (AUROC) curve was used to analyze the contribution of sunlight-related factors and dietary vitamin D intake to vitamin D status stratified by climate zones.

RESULTS

The prevalence of VDD was 30.1% and was the highest in the north. Sufficient intake of red meat (odds ratio (OR): 0.50, 95% confidence interval (CI): 0.32-0.75; p = 0.002), vitamin D and/or calcium supplements (OR: 0.51, 95% CI: 0.39-0.66; p < 0.001), sun exposure (OR: 0.75, 95% CI: 0.57-0.98; p = 0.034), and blood draw during sunny months (OR: 0.59, 95% CI: 0.46-0.77; p < 0.001) were associated with a lower likelihood of VDD. Additionally, in northern Taiwan, which is characterized by a subtropical climate, dietary vitamin D intake (AUROC: 0.580, 95% CI: 0.528-0.633) had a greater influence on vitamin D status than did sunlight-related factors (AUROC: 0.536, 95% CI: 0.508-0.589) with a z value = 51.98, p < 0.001. By contrast, sunlight-related factors (AUROC: 0.659, 95% CI: 0.618-0.700) were more important than dietary vitamin D intake (AUROC: 0.617, 95% CI, 0.575-0.660) among women living in tropical areas of Taiwan (z value = 54.02, p < 0.001).

CONCLUSIONS

Dietary vitamin D intake was essential to alleviate VDD in the tropical region, whereas sunlight-related factors played a greater role in subtropical areas. Safe sunlight exposure and adequate dietary vitamin D intake should be promoted appropriately as a strategic healthcare program.

Vitamin D Supply of Multivitamins Commercialized Online by Amazon in Western and Southern Europe: A Labeling Analysis

Multivitamins are commonly used by the general population, often without medical prescription. The purpose of this report is to inform on the daily vitamin D supply provided by multivitamins containing vitamin D that are commercialized online by Amazon in Western and Southern Europe. We surveyed multivitamins aimed at adults using the following marketplaces: amazon.es®, amazon.de®, amazon.it®, and amazon.fr®. We identified 199 vitamin D3-containing multivitamins sold by Amazon marketplaces: 77 from amazon.es®, 73 from amazon.de®, 33 from amazon.it®, and 16 from amazon.fr®. No multivitamin contained vitamin D2. The daily vitamin D3 supply ranged from 16 to 2000 IU: it was less than 400 IU daily in 108 (54%), 400−800 IU daily in 53 (27%), and more than 800 IU daily in the remaining 38 (19%) products. The vitamin D3 supply of products sold by amazon.it® was on average higher (p < 0.05) than that of products sold by amazon.de®, amazon.fr®, and amazon.es®. In conclusion, the vitamin D supply of multivitamins sold by Amazon may be insufficient, marginally sufficient, or adequate for subjects at high risk of hypovitaminosis D such as subjects 65 years or more of age, pregnant (or lactating) women, or patients on drug treatment or with an underlying disease, where a vitamin D supplementation is advocated.

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.

Serum vitamin D levels and COVID-19 during pregnancy: A systematic review and meta-analysis

Background

Serum vitamin D levels are reported to be associated with the risk of incidence and severity of COVID-19 in the general population. During pregnancy, immune system alterations in line with changes in vitamin D metabolism may affect the course of COVID-19. Thus, we aimed to systematically review the association between vitamin D, pregnancy, and COVID-19.

Methods

A systematic literature search was conducted in PubMed, Scopus, Web of Science, Embase, and Google Scholar until the end of May 2022. Mean differences (MD) with 95% CI were used as desired effect sizes to assess the association of serum vitamin D levels with the risk of incidence and severity of COVID-19 in pregnant women.

Results

Among 259 records, 7 and 6 studies were included in the systematic review and meta-analysis, respectively. All included studies had acceptable quality. Our results demonstrated an insignificant difference between infected women and non-infected controls (MD = -2.55 ng/ml, 95% CI: −6.85 – 1.74). But serum vitamin D levels in severe/moderate cases compared to mild ones (MD = −2.71 ng/ml, 95% CI: −4.18 to −1.24) are significantly lower.

Conclusion

Based on the current evidence, serum vitamin D level does not associate with the risk of SARS-CoV-2 infection among pregnant women, but we find a significant association with the severity of the disease. These findings may be helpful in similar conditions and future studies to better understand the complex immune alterations during pregnancy.

Hypercalcemia in Pregnancy Due to CYP24A1 Mutations: Case Report and Review of the Literature

Pathogenic mutations of CYP24A1 lead to an impaired catabolism of vitamin D metabolites and should be considered in the differential diagnosis of hypercalcemia with low parathyroid hormone concentrations. Diagnosis is based on a reduced 24,25-dihydroxyvitamin D to 25-hydroxyvitamin D ratio and confirmed by genetic analyses. Pregnancy is associated with an upregulation of the active vitamin D hormone calcitriol and may thus particularly trigger hypercalcemia in affected patients. We present a case report and a narrative review of pregnant women with CYP24A1 mutations (13 women with 29 pregnancies) outlining the laboratory and clinical characteristics during pregnancy and postpartum and the applied treatment approaches. In general, pregnancy triggered hypercalcemia in the affected women and obstetric complications were frequently reported. Conclusions on drugs to treat hypercalcemia during pregnancy are extremely limited and do not show clear evidence of efficacy. Strictly avoiding vitamin D supplementation seems to be effective in preventing or reducing the degree of hypercalcemia. Our case of a 24-year-old woman who presented with hypercalcemia in the 24th gestational week delivered a healthy baby and hypercalcemia resolved while breastfeeding. Pathogenic mutations of CYP24A1 mutations are rare but should be considered in the context of vitamin D supplementation during pregnancy.

A Systematic Review of Vitamin D during Pregnancy and Postnatally and Symptoms of Depression in the Antenatal and Postpartum Period from Randomized Controlled Trials and Observational Studies

Depression is a common mood disorder associated with childbirth and is hypothesized to be affected by low vitamin D. This systematic review identified two randomized controlled trials (RCT) of vitamin D supplementation for the treatment or prevention of depressive symptoms in the perinatal period, as well as 18 observational studies of vitamin D exposure and depression in the antenatal and postnatal periods. Both RCTs claimed an improvement in depressive symptoms in the vitamin D group, although the sample sizes were too small to draw firm conclusions. The case-control and cohort studies had mixed findings and were limited by study quality. There were inconsistent results within the few studies with a more robust methodology or within samples restricted to women likely to have depression. The current evidence is inconclusive due to the poor quality and heterogeneity of studies, likely contributing to the contradictory findings. Given there are already numerous RCTs of prenatal vitamin D supplementation, we recommend adding an appropriate measure of depression in the perinatal period to assist in resolving the uncertainty.

Vitamin D Deficiency and Its Clinical Results in Preeclamptic Mothers and Their Babies

Introduction: Vitamin D deficiency during pregnancy may lead to many health problems by negatively affecting the metabolism of the newborn and the mother, such as infantile rickets, poor fetal and neonatal growth and development, gestational diabetes, and preeclampsia. We aimed to investigate the levels and clinical results of vitamin D in preeclamptic mothers and their babies.

Methods: The study group consisted of 42 preeclamptic mothers, and their babies diagnosed with preeclampsia according to the International Society for the Study of Hypertension in Pregnancy (ISSHP) criteria, while the control group consisted of 49 healthy mothers and babies with similar gestational age and birth weight. All pregnant women participating in the study were routinely taking 1200 IU of vitamin D3 daily supplements. The cord blood vitamin D level of both groups of newborns was measured and the results were statistically compared.

Results: The birth week, weight, and height averages and APGAR score averages measured at the first minutes of the babies in the study group (preeclamptic mother babies) were statistically significantly lower than those of the babies in the control group (babies of healthy mothers) (p=0.001, p=0.001, p<0.001, p=0.004, respectively). Vitamin D and calcium levels of the mothers in the study group were lower than those of the mothers in the control group. When the infants were examined, only the level of vitamin D was statistically significantly lower in infants in the patient group (p<0.001, p<0.001, p=0.001, respectively).

Conclusion: There is consistent evidence of an association between low vitamin D concentrations and adverse preeclampsia outcomes. Since vitamin D deficiency is more common in preeclamptic mothers and their infants, higher-dose vitamin D supplementation than routine may be recommended to the patients.

A Probable Way Vitamin D Affects Autism Spectrum Disorder: The Nitric Oxide Signaling Pathway

Vitamin D (VD) deficiency during pregnancy and early brain development is an important environmental risk factor for autism spectrum disorder (ASD). Its specific mechanism of action is still unclear. However, one study on the correlation between metabolomics and VD levels in children with ASD has found that the whole-blood arginine (Arg) levels of children with ASD are significantly negatively correlated with serum VD levels, suggesting that the effect of VD on ASD may be related to the signaling pathway involving Arg. Arg is a precursor of nitric oxide (NO), and changes in its levels most directly affect NO levels and signal transduction pathways. NO, a biologically active free radical, is both a neurotransmitter and a neuromodulator in the central nervous system and is related to the pathogeneses of various neurological diseases. The NO signaling pathway is not only affected by VD levels but also closely related to ASD through a series of mechanisms, such as neurotransmitter imbalance, immune disorders, and oxidative stress. Therefore, the effect of VD on ASD may be achieved via regulation of the NO signaling pathway. The current review discusses the relationship among VD, NO, and ASD as suggested by a large body of evidence in the literature in an effort to provide clues for researchers on the pathogenesis of ASD and the mechanism of VD's impact on ASD.

Placental mRNA and Protein Expression of VDR, CYP27B1 and CYP2R1 Genes Related to Vitamin D Metabolism in Preeclamptic Women

(1) Background: Considerable evidence indicates that the occurrence of preeclampsia (PE) is associated with a reduced vitamin D (VD) level. Several studies have found that VD deficiency is correlated with disturbed trophoblast invasion, reduced angiogenesis and increased vasoconstriction. Because the vitamin D receptor (VDR) and CYP27B1 and CYP2R1 hydrolases are strongly involved in VD metabolism, the goal of the present study was to evaluate their genes and proteins expression in the placentas from preeclamptic women. (2) Methods: Samples and clinical data were obtained from 100 Polish women (41 women with preeclampsia and 59 healthy pregnant controls). The whole PE group was divided into subgroups according to gestation week of pregnancy ending before and after 34 gestational weeks (early/late-onset preeclampsia (EOPE/LOPE)). However, finally, to reduce confounding by differences in gestational age, the EOPE group was excluded from the analysis of mRNA and protein placental expression, and we focus on the comparison between LOPE and control groups. The placental VDR, CYP27B1 and CYP2R1 mRNA expression was analyzed using RT-PCR, and placental protein levels were determined by ELISA assay. (3) Results. (3.1) Placental gene expression: Expression levels of both genes, CYP27B1 (1.17 vs. 1.05 in controls, p = 0.006) and CYP2R1 (2.01 vs. 1.89 in controls, p = 0.039), were significantly higher in preeclamptic placentas than in the control group. Interestingly, VDR expression was significantly lower in placentas from the PE group (1.15 vs. 1.20 in controls, p = 0.030). After dividing all preeclamptic women into subgroups only for the CYP27B1 gene, a significantly higher placental expression in the LOPE subgroup than the healthy controls was observed (padj = 0.038). (3.2) Placental protein expression: The results revealed that protein expression levels of CYP27B1 in the preeclamptic group were similar (5.32 vs. 5.23 in controls, p = 0.530). There was a significant difference in median VDR and CYP2R1 protein levels between studied groups (VDR: 2.56 vs. 3.32 in controls, p < 0.001; CYP2R1: 1.32 vs. 1.43 in controls, p = 0.019). After stratification of preeclamptic women into subgroups, a significant difference was observed only in the VDR protein level. The medians in the LOPE subgroups were significantly lower compared to the healthy control group. In the whole study group, the placental VDR protein level was inversely correlated with systolic and diastolic blood pressure (all p < 0.001), and positively correlated with gestational age (p < 0.001) and infant birth weight (p = 0.014). (4) Conclusions: Lower mRNA and protein expression of VDR in preeclamptic placentas, and also VDR protein expression, could play a pivotal role in preeclampsia development. Additionally, the higher mRNA expression of both CYP27B1 and CYP2R1 hydrolase genes in placentas from preeclamptic women could indicate the compensatory role of these enzymes in preeclampsia etiology. Our results also indicate that placental VDR protein level could be one of the factors modulating blood pressure in pregnant women, as well as influencing gestational age and infant birth weight. Considering the importance of these findings, future studies are warranted.

Maternal Vitamin D Level and Attention-Deficit/Hyperactivity Disorder in Offspring: Getting the Most Out of the Data

We read with great interest the article Sucksdorff et al. "Maternal Vitamin D Levels and the Risk of Offspring Attention-Deficit/Hyperactivity Disorder."¹ We commend the authors for this extraordinary work. Several studies have explored this association lately as well.² It is logistically challenging to conduct this type of study, as it requires long-term follow-up and patient compliance in a vulnerable population. In this letter, we aim to provide a few suggestions for the statistical methodological aspect, which can better guide the clinician in predicting ADHD among offspring.

The Effects of Vitamin D Supplementation During Infancy on Growth During the First 2 Years of Life

CONTEXT

The relationship between maternal and infant vitamin D and early childhood growth remains inadequately understood.

OBJECTIVE

This work aimed to investigate how maternal and child 25-hydroxyvitamin D (25[OH]D) and vitamin D supplementation affect growth during the first 2 years of life.

METHODS

A randomized, double-blinded, single-center intervention study was conducted from pregnancy until offspring age 2 years. Altogether 812 term-born children with complete data were recruited at a maternity hospital. Children received daily vitamin D3 supplementation of 10 μg (group 10) or 30 μg (group 30) from age 2 weeks to 2 years. Anthropometry and growth rate were measured at age 1 and 2 years.

RESULTS

Toddlers born to mothers with pregnancy 25(OH)D greater than 125 nmol/L were at 2 years lighter and thinner than the reference group with 25(OH)D of 50 to 74.9 nmol/L (P < .010). Mean 2-year 25(OH)D concentrations were 87 nmol/L in group 10 and 118 nmol/L in group 30 (P < .001). When group 30 was compared with group 10, difference in body size was not statistically significant (P > .053), but group 30 had slower growth in length and head circumference between 6 months and 1 year (P < .047), and more rapid growth in weight and length-adjusted weight between 1 and 2 years (P < .043). Toddlers in the highest quartile of 25(OH)D (> 121 nmol/L) were shorter (mean difference 0.2 SD score [SDS], P = .021), lighter (mean difference 0.4 SDS, P = .001), and thinner (in length-adjusted weight) (mean difference 0.4 SDS, P = .003) compared with the lowest quartile (< 81.2 nmol/L).

CONCLUSION

Vitamin D and early childhood growth may have an inverse U-shaped relationship.

Nutrition in Reproductive Health: Nutritional Conditioning Factors during Pregnancy and Its Impact on Health

During the gestational period, women need to have optimal health to meet fetal requirements for growth and development. Nutrition is one of the most important factors that can ensure a mother`s health and also that of their offspring. The role of maternal diet, before and during pregnancy, has been associated with adverse birth outcomes and a worsening of maternal health. Medical conditions that are closely related to dietary intake and may affect women before or during pregnancy have also been associated with the appearance of pathology in a newborn. To date, several studies have been carried out in order to identify the role of diet as a factor associated with child physiological and psychological health, both in the short and long term. Educating mothers regarding the influence of maternal dietary intake during pregnancy on infants’ health could represent a simple but effective target for public health policies to improve pregnancy nutrition, and therefore help to avoid newborn diseases through the development.

Why do so many trials of vitamin D supplementation fail?

Our knowledge of vitamin D has come a long way since the 100 years it took for doctors to accept, between 1860 and 1890, that both sunlight and cod liver oil (a well-known folk remedy) cured and prevented rickets. Vitamins D2/D3 were discovered exactly a hundred years ago, and over the last 50 years vitamin D has been found to have many effects on virtually all human tissues and not just on bone health, while mechanisms affecting the actions of vitamin D at the cellular level are increasingly understood, but deficiency persists globally. Observational studies in humans have shown that better provision of vitamin D is strongly associated, dose-wise, with reductions in current and future health risks in line with the known actions of vitamin D. Randomised controlled trials, commonly accepted as providing a 'gold standard' for assessing the efficacy of new forms of treatment, have frequently failed to provide supportive evidence for the expected health benefits of supplementation. Such RCTs, however, have used designs evolved for testing drugs while vitamin D is a nutrient; the appreciation of this difference is critical to identifying health benefits from existing RCT data and for improving future RCT design. This report aims, therefore, to provide a brief overview of the evidence for a range of non-bony health benefits of vitamin D repletion; to discuss specific aspects of vitamin D biology that can confound RCT design and how to allow for them.