Vitamin D deficiency during pregnancy may impair maternal and fetal outcomes

Physiology of Vitamin D-Focusing on Disease Prevention

Vitamin D is a crucial micronutrient, critical to human health, and influences many physiological processes. Oral and skin-derived vitamin D is hydroxylated to form calcifediol (25(OH)D) in the liver, then to 1,25(OH)2D (calcitriol) in the kidney. Alongside the parathyroid hormone, calcitriol regulates neuro-musculoskeletal activities by tightly controlling blood-ionized calcium concentrations through intestinal calcium absorption, renal tubular reabsorption, and skeletal mineralization. Beyond its classical roles, evidence underscores the impact of vitamin D on the prevention and reduction of the severity of diverse conditions such as cardiovascular and metabolic diseases, autoimmune disorders, infection, and cancer. Peripheral target cells, like immune cells, obtain vitamin D and 25(OH)D through concentration-dependent diffusion from the circulation. Calcitriol is synthesized intracellularly in these cells from these precursors, which is crucial for their protective physiological actions. Its deficiency exacerbates inflammation, oxidative stress, and increased susceptibility to metabolic disorders and infections; deficiency also causes premature deaths. Thus, maintaining optimal serum levels above 40 ng/mL is vital for health and disease prevention. However, achieving it requires several times more than the government's recommended vitamin D doses. Despite extensive published research, recommended daily intake and therapeutic serum 25(OH)D concentrations have lagged and are outdated, preventing people from benefiting. Evidence suggests that maintaining the 25(OH)D concentrations above 40 ng/mL with a range of 40-80 ng/mL in the population is optimal for disease prevention and reducing morbidities and mortality without adverse effects. The recommendation for individuals is to maintain serum 25(OH)D concentrations above 50 ng/mL (125 nmol/L) for optimal clinical outcomes. Insights from metabolomics, transcriptomics, and epigenetics offer promise for better clinical outcomes from vitamin D sufficiency. Given its broader positive impact on human health with minimal cost and little adverse effects, proactively integrating vitamin D assessment and supplementation into clinical practice promises significant benefits, including reduced healthcare costs. This review synthesized recent novel findings related to the physiology of vitamin D that have significant implications for disease prevention.

Micronutrients in early life and offspring metabolic health programming: a promising target for preventing non-communicable diseases

Chronic non-communicable diseases are the leading cause of morbidity and mortality worldwide. Developing and implementing effective preventive strategies is the best way to ensure the overall metabolic health status of the population and to counter the global burden of non-communicable diseases. Predisposition to obesity and other non-communicable diseases is due to a combination of genetic and environmental factors throughout life, but the early environment, particularly the environment during the fetal period and the early years of life, is crucial in determining metabolic health, hence the concept of 'fetal programming'. The origins of this causal link between environmental factors and disease lie in epigenetic mechanisms. Among the environmental factors, diet plays a crucial role in this process. Substantial evidence documented the key role of macronutrients in the programming of metabolic diseases early in life. Recently, the effect of maternal micronutrient intake on offspring metabolic health in later life emerged. The purpose of this narrative review is to bring to light available evidence in the literature on the effect of maternal micronutrient status on offspring metabolic health and underlying epigenetic mechanisms that drive this link to highlight its potential role in the prevention of non-communicable diseases.

Deficiency and Insufficiency of Vitamin D in Women of Childbearing Age: A Systematic Review and Meta-analysis

OBJECTIVE

 To estimate the prevalence of inadequate vitamin D level and its associated factors for women of childbearing age in Brazil.

METHODS

 A systematic review was conducted (last updated May 2020). Meta-analyses were performed using the inverse-variance for fixed models with summary proportion calculation by Freeman-Tukey double arcsine. Reporting and methodological quality were assessed using the Joanna Briggs Institute tool for prevalence studies.

RESULTS

 Our review identified 31 studies, comprising 4,006 participants. All the studies had at least one weakness, mainly due to the use of convenience sampling and small sample size. The overall prevalence of vitamin D deficiency, insufficiency, and both deficiency and insufficiency were 35% (confidence interval, 95%CI: 34-37%), 42% (95%CI: 41-44%), and 72% (95%CI: 71-74%), respectively.

CONCLUSION

 Although the magnitude of the prevalence of inadequate levels of vitamin D is uncertain, the evidence suggests that presence of vitamin D deficiency or insufficiency in women of reproductive age can cause moderate to severe problems.

The Effect and Potential Mechanism of Maternal Micronutrient Intake on Offspring Glucose Metabolism: An Emerging Field

Diabetes has become the most common metabolic disease around the world. In addition to genetic and environmental factors in adulthood, the early life environment is critical to the progression of diabetes in adults, especially the environment during the fetal period; this concept is called “fetal programming.” Substantial evidence has illustrated the key role of early life macronutrient in programming metabolic diseases. Recently, the effect of maternal micronutrient intake on offspring glucose metabolism during later life has become an emerging field. This review focuses on updated human and animal evidence about the effect of maternal micronutrient status on offspring glucose metabolism and the underlying mechanism.

Impact of Maternal Vitamin D Status on the Formation of Atopic Dermatitis in Young Children

Recent studies have highlighted relationship of allergic diseases with vitamin D deficiency. The aim of the study was to evaluate the impact of maternal vitamin D levels in pregnancy on the formation of atopic dermatitis in early life. A total of 186 pregnant women and their infants who developed atopic dermatitis before the age of 2 years were involved in the prospective study. Most pregnant women (57.5%) were diagnosed with 25(OH)D deficiency (3.6 ± 4.4 ng/ml) (P = .000). Maternal 25(OH)D deficiency was directly related to atopic family anamnesis and relatively high IgE levels. In these cases, children developed atopic dermatitis before the age of 6 months (70.8%) with prevalence of moderate-severity (55%) and persistent course (68.3%) of the disease. The above mentioned supported the idea that the peculiarities of the formation of atopic dermatitis in young children are associated with low concentrations of vitamin D in mothers during pregnancy.

Differences of Serum 25- (OH) D3 Level and Adverse Pregnancy Outcomes between Women with Gestational Diabetes and Healthy Pregnant Women

Background:

The difference in serum 25-hydroxyvitamin D₃ (25-(OH) D₃ ) level between the gestational diabetes mellitus (GDM) and healthy pregnant women was analyzed, to provide the experimental evidence for the vitamin supplement in pregnant women, especially those with GDM.

Methods:

Pregnant women (n=50) who received prenatal care in the Obstetrical Clinic of Xuzhou Maternity and Child Health Care Hospital in summer and winter of 2016 were enrolled. They were assigned to the summer GDM group, winter GDM group, summer control group and winter control group. The level of serum 25-(OH)D₃ was determined using immunochromatography.

Results:

The mean level of serum 25-(OH)D₃ in pregnant women of four groups was lower than normal level. Compared with control group in corresponding season, the winter and summer GDM groups had significantly lower level of 25-(OH)D₃ than the winter and summer control groups (P<0.05). The winter GDM group had significantly lower level of 25-(OH)D₃ than the summer GDM group (P<0.05). The winter control group had significantly lower level of 25-(OH)D₃ than the summer control group (P<0.05). The percentage of deficient 25-(OH)D₃ level was the highest in winter GDM group. Vitamin D deficiency was severer in pregnant women with GDM than healthy pregnant women. In winter, vitamin D deficiency was severer than that in summer.

Conclusion:

Pregnant women, especially those with GDM, should pay more attention to vitamin D supplementation.

Serum 25-hydroxyvitamin D levels in relation to lipids and clinical outcomes in pregnant women with gestational diabetes mellitus: an observational cohort study

OBJECTIVE

The aim of the present study was to investigate whether 25-hydroxyvitamin D (25(OH)D) status at 24-28 weeks is associated with blood lipids and pregnancy outcomes in patients with gestational diabetes mellitus (GDM).

DESIGN

We performed an observational cohort study.

SETTING

The study was conducted in China.

PARTICIPANTS

A total of 261 pregnant women diagnosed with GDM at 24-28 weeks of gestation in our hospital were included between June 2015 and December 2017. According to the levels of 25(OH)D, the women were divided into the G1 (<20 ng/mL) and G2 (≥20 ng/mL) groups. The levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), TG/HDL-c and TC/HDL-c ratios were obtained from medical records. Pregnancy outcomes included gestational weeks of birth and delivery mode. Newborn information included birth weight and body length. Differences between groups were tested with adjusted multiple linear regression.

RESULTS

The serum levels of 25(OH)D (14.1±3.4 ng/mL vs 28.5±6.5 ng/mL, p<0.001), TC (5.3±0.9 vs 5.6±0.8, p=0.006), HDL-c (1.8±0.4 vs 1.9±0.4, p=0.046) and LDL-c (2.5±0.6 vs 2.7±0.7, p=0.015) in the G2 group were significantly higher than those in G1 group, while TG/HDL-c ratios (1.43±0.7 vs 1.26±0.7, p=0.035) were significantly higher in the G1 group. Moreover, we failed to find a significant difference in pregnancy outcomes of mothers and newborns among the two groups (p>0.05). In models adjusting for maternal age, parity, height, blood pressure, socioeconomic status, educational attainment, pre-pregnancy body mass index, season and gestational age, maternal 25(OH)D was associated with TG/HDL-c ratios (B=-0.016; 95% CI= -0.025 to -0.006).

CONCLUSION

We found that there was no relationship between vitamin D and pregnancy/neonatal outcomes in our study. Maternal 25(OH)D at 24-28 weeks was inversely associated with TG/HDL-c ratios.

Vitamin D during pregnancy and its association with birth outcomes: a Brazilian cohort study

BACKGROUND/OBJECTIVES

Evidence is lacking on how variation in vitamin D concentrations during gestation affects perinatal outcomes. Therefore, we evaluated the association between vitamin D serum concentrations during pregnancy and neonatal outcomes.

METHODS

A prospective cohort of 180 healthy Brazilian pregnant women was followed and plasma 25-hydroxyvitamin [25(OH)D, nmol/L] was measured at 5-13 (baseline), 20-26 and 30-36 gestational weeks. Birth weight (BW), birth length (BL), BW z-scores, BL z-scores, first minute Apgar, small for gestational age (SGA), large for gestational age (LGA) and preterm birth were the outcomes. Multiple linear and Poisson regression models were estimated. Best linear unbiased prediction of random coefficients model was used to determine the association between the mean rate of change in vitamin D during pregnancy concentrations and neonatal outcomes.

RESULTS

Mean (SD) BW was 3300 (600) g, BW z-score 0.34 (1.11), BL 49.3 (3.3) cm, BL z-score 0.44 (1.5), and first minute Apgar score 8.2 (1.4). Prevalence of SGA, LGA and preterm birth were 6%, 18% and 13%, respectively. 25(OH)D was directly associated with the risk of preterm birth at all trimesters. Incidence-rate ratios were 1.02, 1.05 and 1.04 for the 1st, 2nd and 3rd trimester, respectively. Mean rate of change during pregnancy in 25(OH)D was directly associated with BW z-score (β: 0.36, 95% CI 0.07; 0.65), LGA risk (IRR: 1.97, 95% CI 1.07; 3.63) and preterm birth (IRR: 7.35, 95% CI 2.99; 18.07).

CONCLUSIONS

Mean 25(OH)D rate of change during pregnancy was directly associated with BW z-scores, and increased LGA and preterm birth risk.

Maternal exposure to cold spells during pregnancy is associated with higher blood pressure and hypertension in offspring later in life

We aimed to investigate whether month of birth is associated with blood pressure (BP) and prevalent hypertension in adults from a region with frost-free days of <150 days and average temperatures - 13°C in winter, Xinjiang, China. We analyzed data for 6158 subjects from several surveys. We divided participants into April to August (n = 2624) and September to March (n = 3534) groups, based on length of maternal exposure to cold months, and analyzed BP, prevalent hypertension, and related factors. Diastolic BP in total subjects and systolic and diastolic BP in male subjects born between April and August were significantly higher than in those born between September and March. In sensitivity analysis, untreated males born between April and August showed significantly higher systolic and diastolic BP than did their counterparts. Subjects born between April and August showed significantly higher prevalence of hypertension (31.3% vs 27.8%, P = .003), and isolated systolic (23.3% vs 20.8%, P = .018) and diastolic hypertension (24.5% vs 21.4%, P = .004), than those born between September and March, which is similar for men. Birth between April and August showed 1.68 (95% CI: 1.06-2.67, P = .027)-fold increased odds for the prevalence of hypertension, independent of gender, age, body mass index, waist circumference, cigarette consumption, alcohol intake, and family history, compared with their counterparts. In conclusion, maternal exposure to cold spells during pregnancy may be associated with the increased risk of hypertension in offspring later in life, particularly among males, suggesting the involvement of maternal cold exposure during pregnancy in offspring hypertension development.

Associations between prenatal sunshine exposure and birth outcomes in China

This paper is one of the first to examine the associations between prenatal sunshine exposure and birth outcomes, specifically the incidence of low birth weight (LBW) and small for gestational age (SGA), based on a nationally representative birth record dataset in China. During the sample period in the 1990s, migration was limited in rural China, allowing us to address the identification challenges, like residential sorting and avoidance behaviors. We found a nonlinear relationship between the length of sunlight and birth outcomes. In particular, prenatal exposure to increasing sunshine was associated with a reduction in the incidence of LBW and SGA, especially in the second trimester during pregnancy. This finding was consistent with the clinical evidence suggesting positive effects of sunshine on birth outcomes via obtaining vitamin D or relieving maternal stress.

Associations of Maternal Vitamin D Deficiency with Pregnancy and Neonatal Complications in Developing Countries: A Systematic Review

Pregnant women in Asia, the Middle East, Africa and Latin America are at risk of vitamin D deficiency (VDD) and prevalence throughout these regions are among the highest, globally. Maternal VDD has been associated with increased risk of a number of adverse maternal and neonatal health outcomes, yet research from developing countries is limited. We assessed the associations of maternal VDD during pregnancy with adverse health outcomes by synthesizing the literature from observational studies conducted in developing countries. Six electronic databases were searched for English-language studies published between 2000 and 2017. Thirteen studies from seven countries were included in the review. Prevalence of VDD ranged from 51.3% to 100%. Six studies assessed both maternal and neonatal outcomes, four studies assessed only maternal outcomes and three studies assessed only neonatal outcomes. Ten studies showed at least one significant association between VDD and adverse maternal and/or neonatal health outcomes including pre-eclampsia (n = 3), gestational diabetes mellitus (n = 1), postpartum depression (n = 1), emergency cesarean section delivery (n = 1), low birth weight babies (n = 4), small for gestational age (n = 2), stunting (n = 1). However most of these studies (n = 6) also showed no association with multiple health outcomes. Vitamin D assessment methods, criteria applied to define VDD, season and trimester in which studies were conducted varied considerably across studies. In conclusion, this study highlights the need to improve maternal vitamin D status in developing countries in an effort to support best maternal and child health outcomes across these regions. Future research should focus on more unified approaches to vitamin D assessment and preventative approaches that may be embedded into already existing antenatal care settings.

Vitamin D deficiency and pre-eclampsia in Colombia: PREVitD study

PURPOSE

Pre-eclampsia is a multisystem disorder characterized by new-onset hypertension and proteinuria during pregnancy. Pre-eclampsia remains a major cause of maternal death in low-income countries. Vitamin D has a very diverse biological role in cardiovascular diseases. This study will evaluate the association of vitamin D levels and relevance to pre-eclampsia.

METHODS

We conducted a case-control study of women recruited from the GenPE (Genetics and Pre-eclampsia) Colombian registry. This is a multicenter case-control study conducted in eight Colombian cities. 25-Hydroxyvitamin D (25(OH)D) concentration was measured using liquid-chromatography-tandem mass spectrometry from 1013 women with pre-eclampsia and 1015 mothers without pre-eclampsia (controls).

RESULTS

Fifty-two percent of women with pre-eclampsia were vitamin D deficient. The 25(OH)D concentrations were significantly lower in the pre-eclampsia (mean 29.99 ng/mL; 95% CI: 29.40-30.58 ng/mL) group compared to controls (mean 33.7 ng/mL; 95% CI: 33.20-34.30 ng/mL). In the unadjusted model, maternal vitamin D deficiency, defined by maternal 25(OH)D concentration <30 ng/mL, was associated with an increased probability of suffering from pre-eclampsia (OR 2.10; 95% CI, 1.75-2.51). After adjusting for covariates, a similarly increased probability of having pre-eclampsia was observed (OR 2.18; 95% CI, 1.80-2.64) among women with vitamin D deficiency, relative to controls.

CONCLUSION

Although the results suggest that low maternal concentrations of 25(OH)D increase pre-eclampsia risk, this evidence may not be indicative of a causal association. Future studies are needed to confirm a definite causal relationship between concentrations of vitamin D and the risk of pre-eclampsia, by means of powered clinical trials.

Systematic Review of Vitamin D and Hypertensive Disorders of Pregnancy

This narrative systematic review evaluates growing evidence of an association between low maternal vitamin D status and increased risk of hypertensive disorders. The inclusion of interventional, observational, and dietary studies on vitamin D and all hypertensive disorders of pregnancy is a novel aspect of this review, providing a unique contribution to an intensively-researched area that still lacks a definitive conclusion. To date, trial evidence supports a protective effect of combined vitamin D and calcium supplementation against preeclampsia. Conflicting data for an association of vitamin D with gestational hypertensive disorders in observational studies arises from a number of sources, including large heterogeneity between study designs, lack of adherence to standardized perinatal outcome definitions, variable quality of analytical data for 25-hydroxyvitamin D (25(OH)D), and inconsistent data reporting of vitamin D status. While evidence does appear to lean towards an increased risk of gestational hypertensive disorders at 25(OH)D concentrations <50 nmol/L, caution should be exercised with dosing in trials, given the lack of data on long-term safety. The possibility that a fairly narrow target range for circulating 25(OH)D for achievement of clinically-relevant improvements requires further exploration. As hypertension alone, and not preeclampsia specifically, limits intrauterine growth, evaluation of the relationship between vitamin D status and all terms of hypertension in pregnancy is a clinically relevant area for research and should be prioritised in future randomised trials.

Glucocorticoid exposure induces preeclampsia via dampening 1,25-dihydroxyvitamin D3

The pathogenesis of preeclampsia (PE) involves a number of biological processes that may be directly or indirectly affected by glucocorticoid (GC) and vitamin D. GC exposure increases the risk of PE, and 1,25-dihydroxyvitamin D₃ (1,25-(OH)₂D₃) deficiency may result in PE. The purpose of the present study was to confirm the involvement of GC/1,25-(OH)₂D₃ axis in the pathogenesis of PE. In the study, cortisol levels of PE patients were found to be higher than that of non-complicated pregnancies, while 1,25-(OH)₂D₃ were decreased in both PE women and GC-induced PE rats. Mechanically, GC reduced 1,25-(OH)₂D₃ levels via disturbing its biosynthetic and catabolic enzymes, including Cyp3a1,Cyp24a1 and Cyp27b1, especially enhancing the expressions of Cyp3a1, the dominant enzyme for vitamin D degeneration. Moreover, replenishing 1,25-(OH)₂D₃ ameliorated the symptoms and placental oxidative stress of GC-induced rat PE. The protective actions of 1,25-(OH)₂D₃ might be explained by its roles in antagonizing the effects of GC on trophoblast proliferation and apoptosis. Together, these findings suggest that GC exposure could lead to PE via dampening 1,25-(OH)₂D₃ biosynthesis, and GC/1,25-(OH)₂D₃ axis might represent a common pathway through which PE occurs.

Association between maternal vitamin D status during pregnancy and offspring cognitive function during childhood and adolescence

BACKGROUND AND OBJECTIVES

Animal studies have demonstrated poor cognitive outcomes in offspring in relation to maternal vitamin D deficiency before and/or during pregnancy. Human studies linking maternal vitamin D status during pregnancy with offspring cognitive function are limited. We aimed to test the hypothesis that lower maternal vitamin D status during pregnancy is associated with poor offspring cognitive ability in an Indian population.

METHODS AND STUDY DESIGN

Cognitive function was assessed in children from the Mysore Parthenon birth cohort during childhood (age 9-10 years; n=468) and adolescence (age 13-14 years; n=472) using 3 core tests from the Kaufman Assessment Battery for children and additional tests measuring learning, long-term retrieval/ storage, short-term memory, reasoning, verbal fluency, visuo-spatial ability, and attention and concentration. Maternal serum 25-hydroxyvitamin D concentration was measured at 30±2 weeks of gestation.

RESULTS

During pregnancy 320 (68%) women had 'vitamin D deficiency' (serum 25-hydroxyvitamin D concentration <50 nmol/L). Girls scored better than boys in tests of short-term memory, reasoning, verbal fluency, and attention (p<0.05 for all). Maternal vitamin D status (low as well as across the entire range) was unrelated to offspring cognitive function at both ages, either unadjusted or after adjustment for the child's current age, sex, maternal age, parity, season at the time of blood sampling, gestational age, the child's birth and current size, socio-economic status, parents' education, maternal intelligence and home environment.

CONCLUSIONS

In this population, despite a high prevalence of vitamin D deficiency during pregnancy, there was no evidence of an association between maternal vitamin D status and offspring cognitive function.

The effects of vitamin D supplementation during pregnancy and maternal vitamin D levels on neonatal vitamin D levels and birth parameters

OBJECTIVE

The current study aimed to measure the levels of vitamin 25(OH)D in pregnant women and in the umbilical cord blood of newborns and to evaluate the association of vitamin D levels with birth parameters.

METHODS

This cross-sectional analytic investigation was performed in 100 pregnant women at term and in 100 newborns born to these mothers. Plasma vitamin D level was measured and birth parameters of the babies were recorded.

RESULTS

Mean vitamin D levels in pregnant women and cord blood were 11.39 ± 6.24 ng/ml and 8.00 ± 4.95 ng/ml, respectively. Vitamin D levels were found to be higher in the women who had received vitamin D support during pregnancy (p < .001). Height (p = .004), head circumference (p = .003), and chest circumference (p = .005) of newborns born to mothers who had received vitamin D support were higher compared to non-receivers. Maternal vitamin D deficiency (<10 ng/ml) and insufficiency (10-30 ng/ml) was detected in 53.0% and 47.0% of the cases, respectively. None of the women had sufficient levels of vitamin D.

CONCLUSIONS

This study established that vitamin D levels were low in maternal and cord blood in spite of the administration program of Ministry of Health in pregnant women. The importance of vitamin D supplementation should be explained to the pregnant women in each visit.

Plasma Vitamin D Deficiency Is Associated With Poor Sleep Quality and Night-Time Eating at Mid-Pregnancy in Singapore

Plasma 25-hydroxyvitamin D (25OHD) deficiency, poor sleep quality, and night-time eating, have been independently associated with adverse pregnancy outcomes, but their inter-relationships are yet to be evaluated. We aimed to investigate the associations between maternal plasma 25OHD status and sleep quality and circadian eating patterns during pregnancy. Data on pregnant women (n = 890) from a prospective cohort (Growing Up in Singapore Towards healthy Outcomes) were analyzed. Plasma 25OHD concentration was measured, while the Pittsburgh sleep quality index (PSQI) and 24-h dietary recall were administered to women at 26-28 weeks' gestation. Plasma 25OHD status was defined as sufficient (>75 nmol/L), insufficient (50-75 nmol/L), or deficient (<50 nmol/L). Poor sleep quality was defined by a total global PSQI score >5. Predominantly day-time (pDT) and predominantly night-time (pNT) were defined according to consumption of greater proportion of calories (i.e., >50%) from 07:00-18:59 and from 19:00-06:59, respectively. After adjustment for confounders, women with plasma 25OHD deficiency had higher odds of poor sleep quality (odds ratio (OR) 3.49; 95% confidence interval (CI) 1.84-6.63) and pNT eating (OR: 1.85; 95% CI 1.00-3.41) than those who were 25OHD sufficient. Our findings show the association of maternal plasma 25OHD deficiency with poor sleep quality and pNT eating at mid-pregnancy.

Association of Maternal Serum 25-hydroxyvitamin D Concentrations in Second Trimester with Delivery Mode in A Chinese Population

Objective: To determine the maternal serum 25-hydroxyvitamin D [25(OH)D] concentrations in a Chinese population and investigate its associations with subsequent delivery mode by studying 1924 unrelated pregnant women. Methods: The serum 25(OH)D concentrations was measured by euzymelinked immunosorbent assay (ELISA). Simultaneously, maternal information and subsequent delivery mode were collected. Logistic regression analysis was performed to assess the associations between 25(OH)D concentrations and caesarean section. Results: The median (IQR) serum concentration of 25(OH)D for the total subjects was 43.4 (35.2-56.9) nmol/L. Among them, 1225 (63.7%) women were in the status of 25(OH)D deficiency (< 50.0 nmol/L). The 25(OH)D concentrations showed significant variation by body mass index (BMI), parity and season of sampling. Women with caesarean section was older, and with higher BMI and rate of abnormal pregnancy history, suggesting advanced age, obesity and abnormal pregnancy history may be the risk factors for the subsequent caesarean section. Compared with 25(OH)D from 50.0 to 74.9 nmol/L, women with low 25(OH)D concentrations (< 50.0 nmol/L) was not significantly associated with caesarean section. Only in the subgroup of the women without abnormal pregnancy history, higher 25(OH)D (> 75.0 nmol/L) concentrations could significantly decrease the risk of caesarean section. Conclusion: Vitamin D deficiency is a quite serious problem in Chinese pregnant women. There is no evidence that the maternal serum 25(OH)D concentrations is associated with increased risk of caesarean section.

Ultraviolet radiation and effects on humans: the paradigm of maternal vitamin D production during pregnancy

Current evidence indicates that neonates born of mothers with vitamin D deficiency during pregnancy have greater risk for developing hypocalcemia, rickets and extra-skeletal disorders. Despite the classic knowledge that ultraviolet-B (UVB) exposure is the most efficient way for a future mother to obtain optimal vitamin D concentrations, no current consensus or clinical recommendations exist regarding the duration and timing of UVB exposure for pregnant women. This article offers a narrative review of available data regarding how UVB exposure affects maternal vitamin D production during pregnancy, along with a discourse on clinical implications of this public health issue. Future studies would benefit from adopting UVB exposure estimates to recommend appropriate UVB exposure to pregnant women. Doing so could provide a more holistic and practical approach in managing maternal hypovitaminosis D during pregnancy.

Vitamin D Depletion in Pregnancy Decreases Survival Time, Oxygen Saturation, Lung Weight and Body Weight in Preterm Rat Offspring

Animal studies suggest a role of vitamin D in fetal lung development although not studied in preterm animals. We tested the hypothesis that vitamin D depletion aggravates respiratory insufficiency in preterm rat offspring. Furthermore, the effects of vitamin D depletion on growth and lung surfactant were investigated. Female Sprague-Dawley rats were randomly assigned low vitamin D (VD_L) or control diet before mating and followed with serum 25-hydroxyvitamin D (s-25(OH)D) determinations. After cesarean section at gestational day 19 (E19) or day 22 (E22), placental weight, birth weight, crown-rump-length (CRL), oxygenation (SaO₂) at 30 min and survival time were recorded. The pup lungs were analyzed for phospholipid levels, surfactant protein A-D mRNA and the expression of the vitamin D receptor (VDR). S-25(OH)D was significantly lower in the VD_L group at cesarean section (12 vs. 30nmol/L, p<0.0001). Compared to the controls, E19 VD_L pups had lower birth weight (2.13 vs. 2.29g, p<0.001), lung weight (0.09 vs. 0.10g, p = 0.002), SaO₂(54% vs. 69%, p = 0.002) as well as reduced survival time (0.50 vs. 1.25h, p<0.0001). At E22, the VD_L-induced pulmonary differences were leveled out, but VD_L pups had lower CRL (4.0 vs. 4.5cm, p<0.0001). The phospholipid levels and the surfactant protein mRNA expression did not differ between the dietary groups. In conclusion, Vitamin D depletion led to lower oxygenation and reduced survival time in the preterm offspring, associated with reduced lung weight and birth weight. Further studies of vitamin D depletion in respiratory insufficiency in preterm neonates are warranted.

Racial disparities in cord blood vitamin D levels and its association with small-for-gestational-age infants

OBJECTIVE

To examine the relationship of race and maternal characteristics and their association with cord blood vitamin D levels and small-for-gestational-age (SGA) status.

STUDY DESIGN

Cord blood vitamin D levels were measured in 438 infants (276 black and 162 white). Multivariable logistic regression models were used to evaluate associations between maternal characteristics, vitamin D status and SGA.

RESULTS

Black race, Medicaid status, mean body mass index at delivery and lack of prenatal vitamin use were associated with vitamin D deficiency. Black infants had 3.6 greater adjusted odds (95% confidence interval (CI): 2.4, 5.6) of vitamin D deficiency when compared with white infants. Black infants with vitamin D deficiency had 2.4 greater adjusted odds (95% CI: 1.0, 5.8) of SGA. Vitamin D deficiency was not significantly associated with SGA in white infants.

CONCLUSION

Identification of risk factors (black race, Medicaid status, obesity and lack of prenatal vitamin use) can lead to opportunities for targeted prenatal vitamin supplementation to reduce the risk of neonatal vitamin D deficiency and SGA status.

Maternal vitamin D concentrations during pregnancy, fetal growth patterns, and risks of adverse birth outcomes

BACKGROUND

Maternal vitamin D deficiency during pregnancy may affect fetal outcomes.

OBJECTIVE

The objective of this study was to examine whether maternal 25-hydroxyvitamin D [25(OH)D] concentrations in pregnancy affect fetal growth patterns and birth outcomes.

DESIGN

This was a population-based prospective cohort in Rotterdam, Netherlands in 7098 mothers and their offspring. We measured 25(OH)D concentrations at a median gestational age of 20.3 wk (range: 18.5-23.3 wk). Vitamin D concentrations were analyzed continuously and in quartiles. Fetal head circumference and body length and weight were estimated by repeated ultrasounds, and preterm birth (gestational age <37 wk) and small size for gestational age (less than the fifth percentile) were determined.

RESULTS

Adjusted multivariate regression analyses showed that, compared with mothers with second-trimester 25(OH)D concentrations in the highest quartile, those with 25(OH)D concentrations in the lower quartiles had offspring with third-trimester fetal growth restriction, leading to a smaller head circumference, shorter body length, and lower body weight at birth (all P < 0.05). Mothers who had 25(OH)D concentrations in the lowest quartile had an increased risk of preterm delivery (OR: 1.72; 95% CI: 1.14, 2.60) and children who were small for gestational age (OR: 2.07; 95% CI: 1.33, 3.22). The estimated population attributable risk of 25(OH)D concentrations <50 nmol/L for preterm birth or small size for gestational age were 17.3% and 22.6%, respectively. The observed associations were not based on extreme 25(OH)D deficiency, but presented within the common ranges.

CONCLUSIONS

Low maternal 25(OH)D concentrations are associated with proportional fetal growth restriction and with an increased risk of preterm birth and small size for gestational age at birth. Further studies are needed to investigate the causality of these associations and the potential for public health interventions.

Supplementation of Merino ewes with cholecalciferol in late pregnancy improves the vitamin D status of ewes and lambs at birth but is not correlated with an improvement in immune function in lambs

Functional deficiencies of the immune system are known to predispose human and animal neonates to death. Thus, immune competency may be a significant factor influencing the mortality of lambs. Vitamin D has been recognised to improve immune function and is transferred across the placenta. This study tested the hypotheses that (1) supplementation of Merino ewes with cholecalciferol during late pregnancy will increase the concentrations of vitamin D in the ewe and lamb at birth and (2) supplementation of Merino ewes with cholecalciferol during late pregnancy is correlated with an increase in innate phagocytic and adaptive antibody immune responses in the lamb. Merino ewes (n = 53) were injected intramuscularly with 1 × 106 IU cholecalciferol at Days 113 and 141 of pregnancy. A control group (n = 58) consisted of ewes receiving no additional nutritional treatments. The vitamin D status of ewes and lambs was assessed up until 1 month post-lambing. Lamb immune function was assessed by analysing the functional capacity of phagocytes, and the plasma IgG and anti-tetanus-toxoid antibody concentrations between birth and weaning. Maternal supplementation with cholecalciferol increased the plasma 25(OH)D concentrations of both ewes (137 vs 79 nmol/L; P < 0.001) and lambs (49 vs 24 nmol/L; P < 0.001) at birth compared with the controls. Supplementation with cholecalciferol had no significant effect on the phagocytic capacity of monocytes or polymorphonuclear leukocytes, the concentration of IgG in the colostrum or plasma of lambs, or the vaccine-specific antibody response against tetanus toxoid. Overall, the results support our first hypothesis, but suggest that maternal supplementation with 1 × 106 IU cholecalciferol does not improve innate, passive or adaptive immune function in lambs.

Evaluation of the gingival inflammation in pregnancy and postpartum via 25-hydroxy-vitamin D3, prostaglandin E2 and TNF-α levels in saliva

BACKGROUND

Physiological changes and immunological modifications occur during pregnancy. The clinical and biological features of periodontal infections are affected by pregnancy. The aim of the present study was to evaluate saliva levels of 25-hydroxy-vitamin D3 (25(OH)D3), prostaglandin E2 (PGE2) and TNF-alpha (TNF-α) in pregnancy, postpartum and non-pregnant controls.

METHODS

Whole saliva samples together with full-mouth clinical periodontal recordings were obtained from 59 pregnant, 47 post partum and 70 systemically healthy non-pregnant women. Groups were also evaluated according to the periodontal health status. 25(OH)D3, PGE2 and TNF-α levels in the saliva samples were determined by enzyme-linked immunoassays. Data were statistically tested by nonparametrical tests.

RESULTS

Saliva TNF-α and PGE2 levels were significantly lower and 25(OH)D3 levels were significantly higher in the pregnant group than postpartum group (p<0.0001). Saliva TNF-α and 25(OH)D3 levels were significantly higher and PGE2 levels were significantly lower in the control group than postpartum group (p<0.0001). In the pregnant healthy, gingivitis and periodontitis groups saliva TNF-α levels were significantly lower than postpartum and control counterparts (p<0.0001, p=0.032, p=0.003 and p=0.013; p=0.027; p=0.007, respectively). In control healthy, gingivitis and periodontitis groups saliva 25(OH)D3 levels were significantly higher than the postpartum counterparts (p<0.0001, p<0.0001, p=0.002, respectively). In the control healthy and gingivitis groups saliva 25(OH)D3 levels were significantly higher than pregnant healthy and gingivitis (p<0.0001).

CONCLUSIONS

In conclusion, within the limits of the present study it seems that pregnancy have an effect on parameters in saliva in relation to the periodontal status of the women. Further studies are required for better understanding of the impact of periodontal diseases on pregnancy or otherwise.

Effects of Serum 25-hydroxy-vitamin D and Fetal Bone Growth during Pregnancy

Background

This study was conducted to observe the prevalence of vitamin D deficiency during pregnancy and the effects of maternal 25-hydroxy-vitamin D (25-[OH]D) levels on fetal bone growth.

Methods

Five hundred twenty-three Korean pregnant women were randomly recruited and serum 25-(OH)D level was measured. During pregnancy, fetal ultrasonography and serum 25-(OH)D measurements were carried out 3 times in 275 of 523 pregnant women. Fetal biparietal and occipitofrontal diameter, head and abdominal circumference, and femur and humerus length were measured through fetal ultrasonography.

Results

The prevalence of vitamin D deficiency (25-[OH]D<20 ng/mL) based on the 1st serum measurement of 25-(OH)D was 88.9%. There was no association between maternal serum 25-(OH)D level and fetal bone growth. In 275 pregnant women who completed study design, the mean value of 25-(OH)D was 12.97±5.93, 19.12±9.82, and 19.60±9.98 ng/mL at 12 to 14, 20 to 22, and 32 to 34 weeks of pregnancy, respectively and there was an association between the difference of serum 25-(OH)D level between 12 to 14 and 20 to 22 weeks and growth velocity of fetal biparietal diameter between 20 to 22 and 32 to 34 weeks of pregnancy.

Conclusions

This study shows a high prevalence of vitamin D deficiency in Korean pregnant women and the change of serum 25-(OH)D levels is related with the growth of fetal biparietal diameter, however other parameters are not associated with serum 25-(OH)D levels.

Selected vitamin D metabolic gene variants and risk for autism spectrum disorder in the CHARGE Study

BACKGROUND

Vitamin D is essential for proper neurodevelopment and cognitive and behavioral function. We examined associations between autism spectrum disorder (ASD) and common, functional polymorphisms in vitamin D pathways.

METHODS

Children aged 24-60 months enrolled from 2003 to 2009 in the population-based CHARGE case-control study were evaluated clinically and confirmed to have ASD (n=474) or typical development (TD, n=281). Maternal, paternal, and child DNA samples for 384 (81%) families of children with ASD and 234 (83%) families of TD children were genotyped for: TaqI, BsmI, FokI, and Cdx2 in the vitamin D receptor (VDR) gene, and CYP27B1 rs4646536, GC rs4588, and CYP2R1 rs10741657. Case-control logistic regression, family-based log-linear, and hybrid log-linear analyses were conducted to produce risk estimates and 95% confidence intervals (CI) for each allelic variant.

RESULTS

Paternal VDR TaqI homozygous variant genotype was significantly associated with ASD in case-control analysis (odds ratio [OR] [CI]: 6.3 [1.9-20.7]) and there was a trend towards increased risk associated with VDR BsmI (OR [CI]: 4.7 [1.6-13.4]). Log-linear triad analyses detected parental imprinting, with greater effects of paternally-derived VDR alleles. Child GC AA-genotype/A-allele was associated with ASD in log-linear and ETDT analyses. A significant association between decreased ASD risk and child CYP2R1 AA-genotype was found in hybrid log-linear analysis. There were limitations of low statistical power for less common alleles due to missing paternal genotypes.

CONCLUSIONS

This study provides preliminary evidence that paternal and child vitamin D metabolism could play a role in the etiology of ASD; further research in larger study populations is warranted.

Immunomodulatory role of vitamin D in the pathogenesis of preeclampsia

Worldwide, preeclampsia is a significant health risk to both pregnant women and their unborn children. Despite scientific advances, the exact pathogenesis of preeclampsia is not yet fully understood. Meanwhile, the incidence of preeclampsia is expected to increase. A series of potential etiologies for preeclampsia has been identified, including endothelial dysfunction, immunological dysregulation and trophoblastic invasion. In this literature review, we have critically reviewed existing literature regarding the research findings that link the role of vitamin D to the pathogenesis and immunoregulation of preeclampsia. The relationship of vitamin D with the suspected etiologies of preeclampsia underscores its clinical potential in the diagnosis and treatment of preeclampsia.

Maternal and cord blood vitamin D status in high-altitude pregnancy

OBJECTIVE

We aimed to explore the risk factors that may lead to vitamin D deficiency in pregnant women living in moderately high-altitude regions.

METHODS

The study was conducted prospectively between November 2012 and July 2013. City of Erzurum is located at an altitude of 1900-2200 m, north Turkey at 39°4' latitude. Healthy mothers that gave birth after completing 37th week of their pregnancies and healthy neonates weighting >2500 g were included in the study. For 25-hydroxyvitamin D (25(OH)D) analyses venous blood samples of 2 ml were obtained from the umbilical cord and the mother. Questionnaires were developed covering the demographical characteristics and possible risk factors for mothers.

RESULTS

Totally 81 mothers and neonates were included into the study. The mean 25(OH)D level of mothers was 7.1 ± 6.5 ng/ml. It was noted that 45 (55.7%) mothers had severe deficiency. Multivariate linear regression analysis showed that the dressing style and the level of sunlight received by the house were independent factors affecting the level of 25(OH)D.

CONCLUSION

Our findings showed that cultural factors had significant effects on vitamin D levels. We believe that appropriate dose of vitamin D prophylaxis should be administered to pregnant women, considering the risk factors as well as the geographical features.

Vitamin D rescues dysfunction of fetal endothelial colony forming cells from individuals with gestational diabetes

INTRODUCTION

Gestational diabetes (GDM) is associated with long-term cardiovascular and metabolic diseases in offspring. However, the mechanisms are not well understood. We explored whether fetal exposure to a diabetic environment is associated with fetal endothelial progenitor cell dysfunction, and whether vitamin D can reverse the impairment.

METHODS

Nineteen women with uncomplicated pregnancies and 18 women with GDM were recruited before delivery. Time to first appearance of endothelial colony forming cell (ECFC) colonies and number of ECFC colonies formed from culture of cord peripheral blood mononuclear cells were determined. Angiogenesis-related functions of ECFCs in vitro were tested in the presence or absence of vitamin D.

RESULTS

Fetal ECFCs from GDM pregnancies formed fewer colonies in culture (P = 0.04) and displayed reduced proliferation (P = 0.02), migration (P = 0.04) and tubule formation (P = 0.03) compared to uncomplicated pregnancies. Fetal ECFCs exposed to hyperglycemia in vitro exhibited less migration (P < 0.05) and less tubule formation (P < 0.05) than normoglycemic control. Vitamin D significantly improved the dysfunction of fetal ECFCs from pregnancies complicated by GDM or after exposure of healthy ECFCs to hyperglycemia.

DISCUSSION

Fetal ECFCs from GDM pregnancies or ECFCs exposed to hyperglycemia in vitro exhibit reduced quantity and impaired angiogenesis-related functions. Vitamin D significantly rescues these functions. These findings may have implications for vascular function of infants exposed to a diabetic intrauterine environment.

The relationship between low maternal serum vitamin D levels and glycemic control in gestational diabetes assessed by HbA1c levels: an observational cross-sectional study

Background

A great association between vitamin D deficiency and type 2 diabetes mellitus has been suggested in literature. During pregnancy, this deficiency is even more critical. It appears that vitamin D insufficiency during pregnancy may be associated with maternal hazards. The aim of this study was to assess the relation between the levels of 25-hydroxy-cholecalciferol (vitamin D), and the glycemic control in pregnant women.

Methods

An observational cross-section study including 160 pregnant women between 20-40 years in age, in their third trimester, divided into two equal groups. First group consisted of 80 women with established diagnosis of gestational diabetes and the second group with proved normal blood glucose levels. We assessed vitamin D in serum, fasting blood glucose, serum insulin and glycosylated hemoglobin (HbA1c) levels and we depicted the insulin sensitivity using the Quantitative insulin sensitivity check index (Quicki). The results were collected and statistically correlated.

Results

The mean vitamin D levels were 46.61 ± 6.087 and 47.25 ± 10.181in controls and women with gestational diabetes mellitus (GDM) respectively. The fasting insulin levels were significantly higher in the group with GDM with a mean of 18.51 ± 6.44 compared to 8.95 ± 2.52 in the control group.

The correlation coefficient (r) between HbA1c levels and Vitamin D level was -0.492 with a P value <0.05. Similar associations were also found with the fasting blood sugar levels (r = - 0.386) and with Quicki values (r = -0.250). Vitamin D levels correlated significantly with the fasting blood glucose, the fasting serum insulin and the HbA1c levels, the P value in all these correlations were <0.05. The P value with Quicki results was 0.064.

Conclusions

There is a statistically significant negative correlation between the glycemic control and vitamin D levels in serum in the whole study population. The effect of adequate vitamin D replacement on glycemic control was not studied in our work correlation. We suggest larger scale studies addressing this issue.

Maternal vitamin D status and the risk of mild and severe preeclampsia

BACKGROUND

We sought to determine the association between maternal vitamin D status at ≤26 weeks' gestation and the risk of preeclampsia by clinical subtype.

METHODS

We conducted a case-cohort study among women enrolled at 12 US sites from 1959 to 1966 in the Collaborative Perinatal Project. In serum collected at ≤26 weeks' gestation (median 20.9 weeks) from 717 women who later developed preeclampsia (560 mild and 157 severe cases) and from 2986 mothers without preeclampsia, we measured serum 25-hydroxyvitamin D, over 40 years later, using liquid chromatography-tandem mass spectrometry.

RESULTS

Half of women in the subcohort had 25-hydroxyvitamin D (25(OH)D) >50 nmol/L. Maternal 25(OH)D 50 to 74.9 nmol/L was associated with a reduction in the absolute and relative risk of preeclampsia and mild preeclampsia compared with 25(OH)D <30 nmol/L in the crude analysis but not after adjustment for confounders, including race, prepregnancy body mass index, and parity. For severe preeclampsia, 25(OH)D ≥50 nmol/L was associated with a reduction in three cases per 1000 pregnancies (adjusted risk difference = -0.003 [95% confidence interval = -0.005 to 0.0002]) and a 40% reduction in risk (0.65 [0.43 to 0.98]) compared with 25(OH)D <50 nmol/L. Conclusions were unchanged (1) after restricting to women with 25(OH)D measured before 22 weeks' gestation or (2) with formal sensitivity analyses for unmeasured confounding.

CONCLUSIONS

Maternal vitamin D deficiency may be a risk factor for severe preeclampsia but not for its mild subtypes. Contemporary cohorts with large numbers of severe preeclampsia cases would be needed to confirm or refute these findings.

Vitamin D deficiency in pregnant women of ethnic minority: a potential contributor to preeclampsia

OBJECTIVE

We investigated risk for comorbidities and preeclampsia at low vitamin D levels in ethnic minorities.

STUDY DESIGN

Umbilical cord vitamin D (25(OH)D) concentration was determined in urban minorities: 80.9% African American and 17% Hispanic mothers-baby pairs. To identify the correlation between vitamin D levels and high-risk comorbidities which result in preeclampsia, multivariate logistic regression analyses were performed.

RESULT

Below the Institute of Medicine threshold of 25(OH)D for pregnant women (25 ng ml⁻¹), obesity (P=0.055) and pregestational diabetes (odds ratio (OR)=2.056) were observed. The study median was 16 ng ml⁻¹ (<25th percentile), at which gestational hypertension (P=0.042), chronic hypertension (OR=4.842) and pregestational diabetes (OR=3.45) became relevant. The risk for preeclampsia increased 12-fold with gestational hypertension (P=0.003) and 14-fold with combined chronic and gestational hypertension (P=0.001).

CONCLUSION

Pregnant women of ethnic minority had lower median vitamin D levels which may contribute to a potential risk for preeclampsia.

Early origins of adult disease: low birth weight and vascular remodeling

Cardiovascular diseases (CVD) and diabetes still represent the main cause of mortality and morbidity in the industrialized world. Low birth weight (LBW), caused by intrauterine growth restriction (IUGR), was recently known to be associated with increased rates of CVD and non-insulin dependent diabetes in adult life (Barker's hypothesis). Well-established animal models have shown that environmentally induced IUGR (diet, diabetes, hormone exposure, hypoxia) increases the risk of a variety of diseases later in life with similar phenotypic outcomes in target organs. This suggests that a range of disruptions in fetal and postnatal growth may act through common pathways to regulate the developmental programming and produce a similar adult phenotype. The identification of all involved signaling cascades, underlying the physiopathology of these damages in IUGR fetuses, with their influence on adult health, is still far from satisfactory. The endothelium may be important for long-term remodeling and in the control of elastic properties of the arterial wall. Several clinical and experimental studies showed that IUGR fetuses, neonates, children and adolescents present signs of endothelial dysfunction, valuated by aorta intima media thickness, carotid intima media thickness and stiffness, central pulse wave velocity, brachial artery flow-mediated dilation, laser Doppler skin perfusion and by the measure of arterial blood pressure. In utero identification of high risk fetuses and long-term follow-up are necessary to assess the effects of interventions aimed at preventing pregnancy-induced hypertension, reducing maternal obesity, encouraging a healthy life style and preventing childhood obesity on adult blood pressure and cardiovascular disease in later life.

Intrauterine nutrition: long-term consequences for vascular health

There is a growing body of evidence that improper intrauterine nutrition may negatively influence vascular health in later life. Maternal malnutrition may result in intrauterine growth retardation and, in turn, metabolic disorders such as insulin resistance, diabetes, hypertension, and dyslipidemia, and also enhanced risk of atherosclerosis and cardiovascular death in the offspring. Energy and/or protein restriction is the most critical determinant for fetal programming. However, it has also been proposed that intrauterine n-3 fatty acid deficiency may be linked to later higher blood pressure levels and reduced insulin sensitivity. Moreover, it has been shown that inadequate supply of micronutrients such as folate, vitamin B12, vitamin A, iron, magnesium, zinc, and calcium may contribute to impaired vascular health in the progeny. In addition, hypertensive disorders of pregnancy that are linked to impaired placental blood flow and suboptimal fetal nutrition may also contribute to intrauterine growth retardation and aggravated cardiovascular risk in the offspring. On the other hand, maternal overnutrition, which often contributes to obesity and/or diabetes, may result in macrosomia and enhanced cardiometabolic risk in the offspring. Progeny of obese and/or diabetic mothers are relatively more prone to develop obesity, insulin resistance, diabetes, and hypertension. It was demonstrated that they may have permanently enhanced appetites. Their atheromatous lesions are usually more pronounced. It seems that, particularly, a maternal high-fat/junk food diet may be detrimental for vascular health in the offspring. Fetal exposure to excessive levels of saturated fatty and/or n-6 fatty acids, sucrose, fructose and salt, as well as a maternal high glycemic index diet, may also contribute to later enhanced cardiometabolic risk.

Rate of low vitamin D levels in a low-risk obstetric population

INTRODUCTION

The objectives of this study were to determine vitamin D levels at the first prenatal visit in women who had no obstetric risk factors and, if determined to have a low vitamin D level, to evaluate how high-dose treatment affected the vitamin D level by the end of the second trimester.

METHODS

This study was a descriptive, retrospective chart review. Women were identified through electronic database query based on prenatal care initiation. One hundred and four women had a 25-hydroxy (OH) vitamin D (25[OH]D) serum level drawn at the first prenatal visit. Supplementation was recommended with either 2000 or 4000 units of vitamin D3 for women who had vitamin D insufficiency or deficiency. Twenty women who were treated had repeat vitamin D levels drawn at 28 weeks' gestation to evaluate the effectiveness of supplementation.

RESULTS

Descriptive analysis of demographic data of 104 women who had 25(OH)D levels drawn determined there were no significant differences between women who were vitamin D deficient or insufficient and those whose serum levels were in the sufficient range. Vitamin D serum levels revealed that 32 (30.8%) were sufficient (>30 ng/mL), 49 (47.1%) were insufficient (20-29 ng/mL), and 23 (22.1%) were deficient (<20 ng/mL). Twenty women had a repeat measure of 25(OH)D after supplementation, and there was a significant rise in vitamin D level (P < .001) with vitamin D3 supplementation. However, women who took 4000 units had a higher mean rise (13.17 ng/mL) in 25(OH)D than those taking 2000 units (8.79 ng/mL). Twelve of the women (60%) were still insufficient after supplementation with 2000 units of vitamin D3 .

DISCUSSION

This small sample of women demonstrates a significant degree of insufficiency and deficiency in this desert community where sunshine is plentiful. A larger study should be completed to determine ideal supplementation during pregnancy.

The relationship of serum vitamin D with pre-eclampsia in the Iranian women

Vitamin D deficiency may be a risk factor for negative outcome in pregnancy, such as pre-term labour, low birthweight, intrauterine growth retardation and gestational diabetes. This study aimed to evaluate the relationship between vitamin D and pre-eclampsia. This was a case-control study of 59 pre-eclamptic women and 59 healthy pregnant women selected in two hospitals in Ahvaz, Iran. Women with term singleton pregnancy, nulliparous and of reproductive age were selected. Venous blood samples (2 mL) were taken and the level of 25-dihydroxy vitamin D (25-OH-D) was measured. If the levels of 25-OH-D were less than 10 ng mL(-1), between 10 ng mL(-1) and 29 ng mL(-1) and more than 30 ng mL(-1), they were considered as indicating deficient, insufficient and normal 25-OH-D concentrations, respectively. The independent t-test, Mann-Whitney U-test, chi-square and logistic regression were used for analysing the data. Vitamin D deficiency was significantly higher in the pre-eclampsia group [odds ratio (OR) = 24.04, confidence interval (CI) = 2.10-274.8, P = 0.01]. Older women (30-35 years) were more likely to develop pre-eclampsia compared with the control group (OR = 10.36, CI = 2.18-49.09, P = 0.003). The results showed that women with body mass index (BMI) <20 were more likely to develop pre-eclampsia. The ages between 20 years and 30 years and normal BMI were not the risk factors for pre-eclampsia. Vitamin D deficiency has a statistically significant relationship with pre-eclampsia. It seems that the serum vitamin D levels are low in Iranian women because of their particular lifestyle and they may need more than 400 IU day(-1) vitamin D supplement during pregnancy.

Dynamic changes in serum 25-hydroxyvitamin D during pregnancy and lack of effect on thyroid parameters

Background & Aims

To explore vitamin D status and its dynamic changes during pregnancy in women living in Northeast China. The association between 25-hydroxyvitamin D and serum calcium, phosphate and parathyroid hormone was studied. Because vitamin D deficiency or thyroid dysfunction/autoimmunity during pregnancy may lead to similar adverse events, the relationship between 25-hydroxyvitamin D and thyroid parameters was investigated.

Methods

Serum samples of 50 women (aged 22 to 36 years) were selected retrospectively. The samples were collected at gestational 8 weeks ±3 days, 20 weeks ±3 days and 32 weeks ±3 days for measurement of 25-hydroxyvitamin D, calcium, phosphate, parathyroid hormone, and thyroid parameters.

Results

The median 25-hydroxyvitamin D levels were 28.29, 39.23 and 40.03 nmol/L, respectively, from the first to the third trimester. The 25-hydroxyvitamin D concentration during the first trimester was significantly lower than the next two trimesters (p<0.01) and was unchanged between the second and the third trimester. Of these women, 96%, 78% and 76% showed 25-hydroxyvitamin D ≤50 nmol/L during each trimester. Season was associated with 25-hydroxyvitamin D during each trimester (p<0.05), and a significant association was found between calcium and 25-hydroxyvitamin D during the first and the second trimesters. Only triiodothyronine was associated with 25-hydroxyvitamin D in the first trimester (p = 0.024), but statistical significance was only a trend (p = 0.063) after excluding abnormal values. No association was observed between 25-hydroxyvitamin D and phosphate, parathyroid hormone, and other thyroid parameters.

Conclusions

Vitamin D deficiency during pregnancy was prevalent in women from Northeast China who did not use supplementation. No significant relationships were observed between 25-hydroxyvitamin D and thyroid parameters during pregnancy.

Season of birth, neonatal vitamin D status, and cardiovascular disease risk at 35 y of age: a cohort study from Sweden

BACKGROUND

Lower vitamin D status during gestation may be associated with cardiovascular disease risk later in life. No studies have assessed this hypothesis with a follow-up time reaching beyond childhood.

OBJECTIVE

The objective was to assess the link between season of birth, neonatal 25-hydroxyvitamin D₃ [25(OH)D₃] status, and adult cardiovascular disease risk.

DESIGN

Markers of cardiovascular and metabolic disease risk were measured in 284 subjects aged 35 y, born either at the end of the winter or at the end of the summer of 1975. In 275 of these 284 subjects, concentrations of neonatal 25(OH)D₃ were measured in dried blood samples by using a highly sensitive liquid chromatography-tandem mass spectroscopy method.

RESULTS

Subjects born after the winter had lower neonatal 25(OH)D₃ concentrations than did those born after the summer (31.5 compared with 48.5 nmol/L; P < 0.001). In regression analyses adjusted for sex, season of birth, postnatal age at neonatal sample collection, preterm birth, maternal age, education, smoking, fish consumption per week, exercise per week, and current 25-hydroxyvitamin D, higher neonatal 25(OH)D₃ (per 50 nmol/L) was associated with 25.8% (95% CI: 1.0%, 58.4%) higher fasting insulin in adult life, 29.6% (5.1%, 58.4%) higher triglycerides, and 4.64 (95% CI: 1.93, 7.36) mmol/L higher serum cholesterol in women. Neonatal 25(OH)D₃ (per 1 nmol/L) was directly associated with risk of adult overweight (OR: 1.03; 95% CI: 1.01, 1.05) and with adult obesity in women (OR: 1.09; 95% CI: 1.02, 1.17). Neonatal 25(OH)D₃ was not associated with adult aortic pulse wave velocity, blood pressure, fasting glucose, HDL, LDL, or C-reactive protein. Season of birth was not associated with any of the adult outcomes.

CONCLUSIONS

Higher neonatal 25(OH)D₃ was associated with higher fasting insulin, triglyceride, and cholesterol (in women) concentrations and with a higher risk of overweight at 35 y of age but not with other adult cardiovascular disease risk factors.

Resolving Vitamin D Deficiency in the Preconception Period among High-Risk Reproductive Women: A Randomized Controlled Trial

Background:

Although vitamin D deficiency has been linked to potential complications in reproductive women, the recommended intake dosage of this vitamin in populations with high incidence of deficiency in preconception period has not been defined.

Objectives:

The study investigated the effect of consuming a dosage of 2000 IU/day oral vitamin D for 105 days, on serum levels of this vitamin in reproductive women.

Materials and Methods:

229 women with 18-35 years old, who were confirmed to be vitamin D deficient (vitamin D < 75 nmol/L), were randomized into the intervention and control groups and after 15 weeks consumption of the supplement and placebo, their serum samples were obtained.

Results:

At baseline the mean serum levels of vitamin D in the control group was 23.34 ± 15.87 nmol/L and in intervention group was 25.13 ± 18.46 nmol/L, that these values didn’t have any significant difference (P = 0.43), while after intervention, significant differences between the two groups was noticed (P < 0.001). The affecting factors to achieve normal range of vitamin D in the intervention group included basal amounts of vitamin D and two underlying factors based on questionnaire data: use of oral supplements (except vitamin D and calcium) in daily life and perfect sun exposure.

Conclusion:

This study showed positive effect of the 2000 IU/day oral vitamin D on the serum level elevation of this vitamin in reproductive women.