Vitamin D insufficiency is common in Indian mothers but is not associated with gestational diabetes or variation in newborn size

From cultural dispositions to biological dimensions: a narrative review on the synergy between oral health and vitamin D through the lens of Indian habitus

Oral health is intricately related to systemic health, with new worldwide research demonstrating vitamin D's critical role in sustaining dental and periodontal health. Vitamin D regulates calcium and phosphate metabolism, which is required for the formation and maintenance of healthy teeth and bones. According to research, vitamin D deficiency may contribute to the etiology of periodontal disease by decreasing the host immune response, making it more susceptible to infections like gingivitis and periodontitis. Oral health in India is a tapestry of traditional practices, socioeconomic factors, lifestyle factors, and access to modern healthcare, all of which are intricately linked with the concept of habitus, which refers to deeply embedded habits, dispositions, and practices shaped by an individual's social space. Deep-rooted social and cultural influences have a substantial impact on oral hygiene practices, food patterns, and health-seeking behaviours. Oral diseases are considered as a worldwide health issue. Though standard Western medicine has had effectiveness in preventing and treating periodontal diseases and other oral disorders, the hunt for alternative solutions continues, and natural phytochemicals extracted from plants used in traditional medicine are regarded as viable alternatives to synthetic chemicals. India's traditional medical knowledge and practice, take a comprehensive approach to oral health, emphasizing the balance of physiological components and the use of natural treatments to maintain oral hygiene and treat oral disorders. However, the structural integrity of teeth and optimal oral health can be accomplished by combining Indian traditional medical practices with vitamin D supplementation, which has synergistic attributes for gum health, anti-inflammatory effects, and dental caries prevention. Nevertheless, the unique association of oral health, vitamin D deficiency and the habitus from Indian perspective is extremely underrepresented in academia. To the best of our knowledge, in the aforementioned context, the present narrative review is probably the maiden attempt to discern the crosstalk of oral health and Vitamin D from the perspectives of Indian habitus.

Association of VDR gene variant rs2228570-FokI with gestational diabetes mellitus susceptibility in Arab women

Gestational diabetes mellitus (GDM) has been linked with adverse pregnancy outcomes. Vitamin D receptor (VDR) gene variants have been associated with diabetes mellitus susceptibility and related complications. This study assessed the association between VDR gene polymorphism (rs2228570) and GDM risk among pregnant Arab women. A total of 368 pregnant Saudi women who were screened for GDM at 24-28 weeks of gestation and genotyped for the VDR gene variant (rs2228570) were included in this cross-sectional study. Circulatory insulin levels, fasting blood glucose (FBG), glycated hemoglobin (HbA1c), and vitamin D (25(OH)D) were measured. There were 108 women with GDM and 260 women without GDM. The genotype frequency of women with GDM was CC 60.2 %, CT 33.3 %, TT 6.9 %, and CT + TT 39.8 %; for non-GDM women, were CC 61.1 %, CT 31.5 %, TT 6.9 %, and CT + TT 38.4 %. No association was found between the VDR gene variant (rs2228570-FokI) and GDM susceptibility after adjustment for covariates. Serum 25(OH)D had a significant inverse association with FBG (r = -0.49, p = 0.01) and HbA1c (r = -0.45, p = 0.03) among carriers of the TT-genotype. Furthermore, a significant inverse correlation was observed between serum 25(OH)D and HOMA-β (r = -0.20, p = 0.035) in individuals with the T-allele. Among pregnant Saudi women, glycemic indices appear to be influenced by vitamin D, suggesting a possible role it may play in mitigating the metabolic changes associated with GDM, particularly among individuals with specific genetic backgrounds. In our study population, rs2228570-FokI did not appear to be a significant contributor to GDM risk.

Low levels of Vitamin D during pregnancy associated with gestational diabetes mellitus and low birth weight: results from the MAASTHI birth cohort

Introduction

India has a high prevalence of Vitamin D insufficiency among women of childbearing age. In this study, we aimed to evaluate the potential relationship between Vitamin D deficiency and gestational diabetes mellitus (GDM) and low birth weight (LBW) of newborns in the "Maternal antecedents of adiposity and studying the transgenerational role of hyperglycaemia and insulin" (MAASTHI) birth cohort.

Methods

A prospective cohort study involving 230 participants was conducted in public hospitals located in urban Bengaluru, India. Healthy pregnant women who visited these hospitals for antenatal care (ANC) and who were between 14 and 36 weeks of gestational age were recruited after obtaining their informed consent. An oral glucose tolerance test (OGTT) was administered between 24 and 36 weeks of pregnancy and blood samples were preserved at -80°C for Vitamin D analysis. Follow-up at birth included recording the child's birth weight.

Results

We found that 178 (77.4%) of the study participants were vitamin D deficient, 44 (19.1%) were diagnosed with GDM, and 64 (27.8%) gave birth to LBW babies. Women in the lowest quartile of serum Vitamin D levels had three times higher odds of developing GDM than women in the higher quartiles [OR = 3.22 (95% CI: 1.03, 10.07), p = 0.04] after adjusting for age, parity, socioeconomic status, season, and adiposity. For every one-unit increase in Vitamin D levels, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) decreased by nearly 18%. Furthermore, causal mediation analysis showed that a decrease in one unit of Vitamin D is associated with a decrease of 0.015 units of fasting blood sugar (FBS) and 0.019 units of postprandial blood sugar (PPBS) as it flows through the mediator variable insulin resistance. Vitamin D-deficient women were twice at risk of giving birth to LBW babies (OR 2.04, 95% CI 0.99, 4.19, p = 0.05).

Discussions

Low levels of Vitamin D during pregnancy are associated with a greater risk of pregnant women developing GDM and giving birth to LBW babies in urban Bengaluru.

Associations of free, bioavailable and total 25-hydroxyvitamin D with neonatal birth anthropometry and calcium homoeostasis in mother-child pairs in a sunny Mediterranean region

Sufficient vitamin D status is crucial for successful pregnancy and fetal development. The assessment of 25-hydroxyvitamin D (25(OH)D) concentrations is commonly used to evaluate vitamin D status. Our objective was to examine the interrelated biodynamics of maternal and neonatal total, free and bioavailable 25(OH)D in maternal-neonatal dyads at birth and their associations with homeostasis and neonatal birth anthropometry. We analysed a cohort of seventy full-term mother-child pairs. We found positive associations between all neonatal measures of vitamin D status. Maternal forms exhibited a similar pattern of association, except for the bioavailable maternal form. In multivariate analysis, both total and free maternal 25(OH)D concentrations were correlated with all neonatal forms (neonatal total 25(OH)D: 1·29 (95 % CI, 1·12, 1·46) for maternal total 25(OH)D, 10·89 (8·16, 13·63) for maternal free 25(OH)D), (neonatal free 25(OH)D: 0·15 for maternal total 25(OH)D, 1·28 (95 % CI, 0·89, 1·68) for maternal free 25(OH)D) and (0·13 (95 % CI, 0·10, 0·16), 1·06 (95 % CI, 0·68, 1·43) for maternal free 25(OH)D), respectively, with the exclusion of the bioavailable maternal form. We observed no significant interactions within or between groups regarding maternal and neonatal vitamin D parameters and maternal calcium and parathyroid hormone concentrations, and neonatal birth anthropometry. Our study indicates that bioavailable maternal and neonatal 25(OH)D have no significant effects on vitamin D equilibrium, Ca homeostasis and neonatal anthropometry at birth. However, we observed an interaction between maternal and neonatal total and free 25(OH)D concentrations at the maternal-neonatal interface, with no associations observed with other calciotropic or anthropometric outcomes.

The Degree of Prepregnancy Vitamin D Deficiency Is Not Associated With Gestational Diabetes in Women Undergoing ART

Context

Gestational diabetes mellitus (GDM) is a common pregnancy complication, particularly in women undergoing assisted reproductive technology (ART). An association of GDM with vitamin D in women conceiving naturally has been described; however, studies have yielded heterogeneous results.

Objective

To analyze the association between prepregnancy total and free vitamin D and GDM incidence in women undergoing ART.

Methods

Post hoc analysis of a prospective study at the Reproductive and Genetic Hospital of CITIC-Xiangya in Changsha, China. Total and free vitamin D were measured 1 day before embryo transfer. The patients were screened for GDM using the oral glucose tolerance test.

Results

A total of 1593 women were included in the study, among whom 256 (16.1%) developed GDM. According to international guidelines for total 25-hydroxyvitamin D [25(OH)D], 47 (2.9%) patients had sufficient (≥30 ng/mL) levels, while 696 (43.7%) were insufficient (20 to <30 ng/mL) and 850 (54.4%) were deficient (<20 ng/mL). Comparing GDM and non-GDM patients, there was no significant difference in total nor free vitamin D levels (P = .340 and .849). Similarly, analysis of GDM rates by quintiles of total and free 25(OH)D showed no significant association in one-way ANOVA (P = .831 and .799). Multivariate logistic regression, considering age, BMI, and fasting glucose, also did not show a significant influence of the 2 vitamin D forms on GDM incidence (P = .266 and .123 respectively).

Conclusion

In this relatively vitamin D deficient/insufficient ART cohort, the degree of neither total nor free vitamin D deficiency before pregnancy was associated with the occurrence of GDM.

Maternal vitamin D status in early pregnancy and its association with gestational diabetes mellitus in Shanghai: a retrospective cohort study

Background

There is growing interest regarding vitamin D and its potential role in gestational diabetes mellitus (GDM). We aimed to assess maternal vitamin D status in early pregnancy and its relationships with the risk of GDM in a Chinese population in Shanghai.

Methods

The retrospective cohort study included a total of 7816 pregnant women who underwent a 75-g oral glucose tolerance test (OGTT) during 24–28 weeks of gestation. Participants’ demographic information including maternal age, prepregnancy body mass index (BMI), gestational age, parity, season of blood collection, serum 25-hydroxy vitamin D [25(OH)D] data and other blood biomarker data at 6 to 14 weeks of gestation were retrospectivly extracted from the medical records in the hospital information system.

Results

In the cohort, the prevalence of GDM was 8.6% and the prevalence of vitamin D deficiency and insufficiency in early pregnancy was 53.1 and 38.5%, respectively. The mean value of the serum 25(OH)D concentration was 19.6±7.5 ng/mL. The restricted cubic splines model showed an inverted J-shaped relationship in which the risk of GDM decreased when the 25(OH)D concentrations were ≥ 20 ng/mL. Logistic model analysis showed that 25(OH)D concentrations ≥ 30 ng/mL significantly decreased the risk of GDM (odds ratio = 0.63, 95% confidence interval: 0.45-0.89; P = 0.010) compared with 25(OH)D concentrations < 20 ng/ml.

Conclusions

In early pregnancy, vitamin D deficiency and insufficiency were very common, and a high level of vitamin D showed protective effects against the incidence risk of GDM.

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

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

Vitamin D-Related Risk Factors for Maternal Morbidity during Pregnancy: A Systematic Review

Vitamin D has well-defined classical functions related to metabolism and bone health but also has non-classical effects that may influence pregnancy. Maternal morbidity remains a significant health care concern worldwide, despite efforts to improve maternal health. Nutritional deficiencies of vitamin D during pregnancy are related to adverse pregnancy outcomes, but the evidence base is difficult to navigate. The primary purpose of this review is to map the evidence on the effects of deficiencies of vitamin D on pregnancy outcome and the dosage used in such studies. A systematic search was performed for studies on vitamin D status during pregnancy and maternal outcomes. A total of 50 studies came from PubMed, 15 studies came from Cochrane, and 150 studies came from Embase, for a total of 215 articles. After screening, 34 were identified as candidate studies for inclusion. Finally, 28 articles met the inclusion criteria, which originated from 15 countries. The studies included 14 original research studies and 13 review studies conducted between 2012 and 2021. This review was finally limited to the 14 original studies. This systematic review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, and the quality and strength of the evidence was evaluated using the Navigation Guide Systematic Review Methodology (SING). We found evidence that supports the idea that supplementary vitamin D for pregnant women is important for reducing the risk of gestational diabetes, hypertension, preeclampsia, early labor, and other complications. The data retrieved from this review are consistent with the hypothesis that adequate vitamin D levels might contribute to a healthy pregnancy.

Vitamin D Metabolite Ratio in Pregnant Women with Low Blood Vitamin D Concentrations Is Associated with Neonatal Anthropometric Data

Existing evidence on the correlation between maternal vitamin D concentrations and birth outcomes is conflicting. Investigation of these associations requires accurate assessment of vitamin D status, especially in individuals with low 25-hydroxyvitamin D (25(OH)D) concentrations. This study examined the correlations between birth outcomes and the maternal vitamin D metabolite ratio (VMR) 1 (defined as the ratio of 24,25(OH)2D3 to 25(OH)D) and VMR2 (defined as the ratio of 3-epi-25(OH)D3 to 25(OH)D) using data from the Japan Environment and Children's Study at Chiba Regional Center. A total of 297 mother-neonate pairs were analyzed. Using liquid chromatography-tandem mass spectrometry, we measured 25(OH)D2, 25(OH)D3, 24,25(OH)2D3, and 3-epi-25(OH)D3 concentrations in maternal serum samples. These data were analyzed in relation to birth anthropometric data using multivariable linear regression. Of the study participants, 85.2% showed insufficient vitamin D concentrations. VMR1 was strongly correlated with 25(OH)D concentrations, whereas VMR2 showed a weak correlation. Only VMR2 was associated with all anthropometric data. VMR2 in pregnant women with low vitamin D blood concentrations is a useful marker for neonatal anthropometric data and is independent of 25(OH)D. Accurate measurement of vitamin D metabolites could help better understand the effects of vitamin D on birth outcomes.

Vitamin D Status and Gestational Diabetes in Russian Pregnant Women in the Period between 2012 and 2021: A Nested Case-Control Study

Several meta-analyses found an association between low maternal serum 25-hydroxyvitamin D (25(OH)D) level and gestational diabetes mellitus (GDM). However, some of them reported significant heterogeneity. We examined the association of serum 25(OH)D concentration measured in the first and in the second halves of pregnancy with the development of GDM in Russian women surveyed in the periods of 2012−2014 and 2018−2021. We conducted a case−control study (including 318 pregnant women) nested on two previous studies. In 2012−2014, a total of 214 women (83 GDM and 131 controls) were enrolled before 15 weeks of gestation and maternal serum 25(OH)D concentrations were measured twice: at 8th−14th week of gestation and simultaneously with two-hour 75 g oral glucose tolerance test (OGTT) at 24th−32nd week of gestation. In the period of 2018−2021, 104 women (56 GDM and 48 controls) were included after OGTT and 25(OH)D concentrations were measured at 24th−32nd week of gestation. Median 25(OH)D levels were 20.0 [15.1−25.7] vs. 20.5 [14.5−27.5] ng/mL (p = 0.565) in GDM and control group in the first half of pregnancy and 25.3 [19.8−33.0] vs. 26.7 [20.8−36.8] ng/mL (p = 0.471) in the second half of pregnancy, respectively. The prevalence rates for vitamin D deficiency (25(OH)D levels < 20 ng/mL) were 49.4% and 45.8% (p = 0.608) in the first half of pregnancy and 26.2% vs. 22.1% (p = 0.516) in the second half of pregnancy in women who developed GDM and in women without GDM, respectively. The frequency of vitamin D supplements intake during pregnancy increased in 2018−2021 compared to 2012−2014 (p = 0.001). However, the third trimester 25(OH)D levels and prevalence of vitamin D deficiency (25.5 vs. 23.1, p = 0.744) did not differ in women examined in the periods of 2012−2014 and 2018−2021. To conclude, there was no association between gestational diabetes risk and maternal 25(OH)D measured both in the first and in the second halves of pregnancy. The increased prevalence of vitamin D supplements intake during pregnancy by 2018−2021 did not lead to higher levels of 25(OH)D.

Impact of maternal hypovitaminosis D on birth and neonatal outcome - a prospective cohort study

OBJECTIVE

Vitamin D deficiency in pregnant women is of special concern as mother is the only source of vitamin D for the developing fetus, and maternal hypovitaminosis D has been implicated in a number of maternal and neonatal adverse outcomes. The objective of this study was to assess the association of maternal circulating 25-hydroxy vitamin D3 [25(OH)D] concentration with cord blood 25(OH)D and adverse birth and neonatal outcomes.

METHODS

This prospective cohort study was conducted in Mahatma Gandhi Medical College and Research Institute (MGMCRI) from January 2020 to December 2020. 121 babies born to mothers with singleton pregnancy tested for serum 25(OH)D level on admission for safe confinement were included in the study and cord blood of the babies were sampled for 25(OH)D. Based on the maternal 25(OH)D level, babies were categorized as those born to mothers with sufficient vitamin D level and those born to mothers with hypovitaminosis D (deficient/insufficient) and primary and secondary outcome was compared between two groups.

RESULTS

Maternal and cord blood hypovitaminosis D was observed in 65% of mothers and 68.6% of babies, respectively. Maternal vitamin D level was the single most significant predictor of cord blood vitamin D level with five-fold increased risk of cord blood hypovitaminosis D in babies born to mothers with hypovitaminosis D. Birthweight (t = -2.219, p = .028) and preterm birth (aOR = 4.417, 95% CI: 1.03-18.9) was significantly associated with maternal hypovitaminosis D and a trend toward increased risk of LBW (aOR - 2.1, 95%CI: 0.6-7.3), SGA babies (aOR - 1.5, 95% CI: 0.5-4.7), perinatal depression (aOR - 1.5, 95% CI: 0.4-5.8) and neonatal hyperbilirubinemia (aOR = 2.68, 95%CI: 0.942-7.6) was observed.

CONCLUSIONS

Hypovitaminosis D in pregnant women is a significant health issue affecting both the mother and her baby. Safest dose for supplementation during pregnancy to prevent adverse perinatal outcome needs to be evaluated.

Maternal vitamin D deficiency and GDM risk: evidence for the case of investing more attention in antenatal clinics

Gestational diabetes mellitus (GDM) is a global public health problem, and in India, it affects about 20% of pregnancies. India, despite being a tropical country with abundant sunshine has a high prevalence (80%) of vitamin D deficiency (VDD) among reproductive-aged women. Global and Indian evidence links VDD with a higher risk of hyperglycaemia in pregnancy and GDM. VDD has also been implicated in gestational hypertension, preterm birth and poorer offspring health. Global scientific consensus acknowledges the need for maternal vitamin D screening and supplementation, but knowledge gaps exist about optimal blood levels (50-100 nmol/l), and the required vitamin D dosage (400-4000 IU). Diet can provide <10% of the vitamin D requirements, food fortification can deliver limited amounts, and hence optimal antenatal supplementation is key. Prenatal calcium supplements containing 400 IU of vitamin D may be sufficient for calcium absorption and bone health, but may not provide immunomodulatory benefits, including GDM prevention. Increasing evidence calls for higher maternal vitamin D requirements (2000-4000 IU) for skeletal, metabolic and immune health benefits. Current screening and supplementation for maternal VDD in India is low. We need to invest in future studies to determine optimal maternal vitamin D requirements and formulate policies for vitamin D supplementation to prevent GDM. Improving the maternal vitamin D status is an important nutritional priority for policymakers to reduce the large economic burden of non-communicable diseases (10% of India's gross domestic product), and eventually achieve the 2030 UN sustainable development goals.

Pooled estimate of vitamin D deficiency among pregnant women in India: a systematic review and meta-analysis

BACKGROUND

Vitamin D deficiency among pregnant women is a public health concern globally. In India, individual studies report high prevalence. However, lack of national data masks the true burden. This work determined the pooled prevalence of vitamin D deficiency among pregnant women in India through a systematic review of literature and meta-analysis.

METHODS

Three different search engines yielded 15 eligible articles. Study quality was assessed by 10 different criteria and summary of study quality was categorized as per Cochrane standards. Meta-analysis was performed to estimate pooled prevalence of vitamin D deficiency among healthy pregnant women and heterogeneity among selected studies. A sample of n = 4088 was used to study the pooled prevalence among pregnant women.

RESULTS

The random effects combined estimate was 32.35% (95% CI, (12.58-117.48). High heterogeneity (tau² = 0.39, I² = 100%) and high risk of bias was observed among the selected studies. The test for overall effect was observed to be z = 2.54(P = 0.01).

CONCLUSION

Pooled estimate > 30% emphasizes the need for screening through antenatal care services and initiate preventive measures to address the deficiency.

Maternal vitamin D status and risk of gestational diabetes mellitus: A systematic review and meta-analysis of prospective cohort studies

BACKGROUND

No earlier systematic review and meta-analysis have been done on the association between maternal serum vitamin D status and risk of GDM among prospective studies. The current study was done to systematically review prospective cohort studies (with several years of follow-up) on the association between maternal serum vitamin D deficiency or insufficiency and risk of GDM.

METHODS

Relevant papers published up to January 2020 were searched through PubMed, MEDLINE, SCOPUS, EMBASE, and Google Scholar using suitable keywords. All prospective cohort studies reporting Hazard Ratios (HRs) or Relative Risks (RRs) and 95% Confidence Intervals (CI) for GDM across categories of maternal serum vitamin D status were included.

RESULTS

A total of 29 prospective and nested case-control studies were included in the current systematic review, of which 27 studies had sufficient data for the meta-analysis. Individuals with vitamin D deficiency had a 26% greater risk of developing GDM than those with normal serum vitamin D concentrations (OR: 1.26; 95% CI: 1.13, 1.41). In addition, a significant positive association was seen between combined vitamin D insufficiency and deficiency and risk of developing GDM (OR: 1.23; 95% CI: 1.11, 1.35). Dose-response analysis showed a significant U-shaped non-linear association between serum vitamin D concentrations and risk of developing GDM (P < 0.001), such that those with serum vitamin D concentrations between 40 and 90 nmol/L had significantly reduced risk of GDM.

CONCLUSIONS

We found a significant association between vitamin D deficiency and an increased risk of GDM. The lowest risk of GDM was found among those with a serum vitamin D levels of 40-90 nmol/L. Further studies, including randomized clinical trials, are needed to confirm our findings.

REGISTRATION

PROSPERO (ID: 180722), https://www.crd.york.ac.uk/prospero/.

Prevalence of Gestational Diabetes Mellitus and Its Associated Risk Factors in Boo-Ali Hospital, Tehran

BACKGROUND

Gestational diabetes mellitus (GDM) represents the most common metabolic complication during pregnancy. GDM is associated with maternal and fetal complications. Approximately 7% of all pregnancies are affected by GDM, resulting in more than 200,000 cases worldwide annually, and the prevalence may vary from 1% to 14% among all pregnancies. Accordingly, this study attempted to determine the prevalence and some risk factors of GDM.

MATERIALS AND METHODS

This hospital-based cross-sectional study was carried out at Boo-Ali hospital in Tehran, the capital of Iran. Four hundred non-diabetics pregnant women with a gestational age of 24-28 weeks who attended the Boo-Ali hospital outpatient department were included in our study. Demographic and anthropometric data including age, gravida, para, gestational age, family history of diabetes, history of GDM, weight, height, and body mass index (BMI) were collected. Blood samples were collected from the women at 24-28 weeks to diagnose GDM by oral glucose tolerance test (OGTT). We measured the 25-OH-D level in participants at 24-28 weeks.

RESULTS

Among the 400 pregnant women, 46 (11.5%) had GDM based on OGTT, and the mean age of GDM women were 30.78± 5.96 years. Among selected variables, BMI ≥25kg/m2, family history, and GDM history were associated with increased risks of GDM (odds ratio=2.49, 95% confidence interval [CI] 1.22-5.07;3.52, 95% CI 1.84-6.70; 19.57, and 95% CI 6.16-62.17, respectively). The association was more robust in the positive GDM history of women.

CONCLUSION

High prevalence of GDM highlights more attention of health-care givers in screening pregnant women with risk factors. BMI as a modifiable risk factor for GDM needs more attention, and positive family history and previous GDM history should be considered in the core activities of pregnant women.

Influence of vitamin D binding protein polymorphism, demographics and lifestyle factors on vitamin D status of healthy Malaysian pregnant women

BACKGROUND

Vitamin D deficiency (VDD) has been related to vitamin D binding protein (GC) gene polymorphism, demographics and lifestyle factors in different populations. However, previous studies only focused on demographic and lifestyle factors or genetic factors alone. Therefore, this cross-sectional study aimed to assess the association between GC gene polymorphism, demographics and lifestyle factors with VDD among Malaysian pregnant women.

METHOD

Information on demographic characteristics, dietary vitamin D intake from supplement and food, time spent outdoors, skin type and clothing were collected using a questionnaire. Plasma total 25-hydroxyvitamin D (25OHD) levels were measured using an Ultra-High-Performance Liquid Chromatography (UHPLC). Maternal GC single nucleotide polymorphisms (SNPs) (rs4588 and rs7041) were determined using restriction fragment length polymorphism (RFLP) technique.

RESULTS

Results showed that 50.2% of pregnant women were vitamin D deficient (25OHD < 30 nmol/L). VDD (25OHD < 30 nmol/L) was significantly associated with age, veiled clothing, maternal vitamin D intakes from both food and supplements, and GC rs7041(and GC diplotypes). In contrast to previous studies that reported for non-pregnant population, a significant positive association was found between CC genotype for SNP GC rs7041, GC 1s-1s and GC If-2 with risk of VDD (25OHD < 30 nmol/L).

CONCLUSIONS

The high prevalence of maternal VDD found in this study suggests the need for urgent development and implementation of vitamin D supplementation or fortification strategies to reduce VDD among pregnant women. The discrepancy in the association between GC rs7041 gene polymorphism and VDD reflects the variation in the factors associated with VDD in pregnancy compared to non-pregnant state.

Prevention and Management of Gestational Diabetes Using Vitamin D Supplementation: An Overview and Appraisal of Clinical Trials

A number of studies have examined the role of vitamin D in reproductive processes and disorders of pregnancy such as gestational diabetes mellitus (GDM). Although observational studies have linked maternal vitamin D deficiency with a plethora of adverse pregnancy outcomes including GDM, intervention trials generally do not support the use of vitamin D supplementation for GDM prevention or management. This narrative review provides an up-to-date overview and critical appraisal of randomised controlled trials (RCTs) to describe the current state of knowledge regarding the efficacy of vitamin D supplementation for preventing and/or managing GDM. Overall, although RCT data indicates a potential benefit of vitamin D in maternal glycaemic control, results are highly disparate and the data published to date have not conclusively established the efficacy of vitamin D in GDM prevention. There are, however, several limitations within the existing literature, including some considerable challenges that are unique to vitamin D trials, which should be carefully considered in the interpretation of the evidence and design of future studies. For now, many unanswered questions remain, and there is still a need for adequately powered and well-designed trials before routine supplementation can be recommended in the context of GDM.

The Influence of Maternal Levels of Vitamin D and Adiponectin on Anthropometrical Measures and Bone Health in Offspring

BACKGROUND

From the conception onward, certain parameters associated with maternal health may affect foetal body composition, growth and bone mineral content. The objective of the study was to determine the association between maternal vitamin D and adiponectin status with the anthropometrical measures of newborns, and bone health status measured by Quantitative Ultrasound (QUS) at birth.

METHODS

Circulating 25OHD and adiponectin concentration were measured in 73 pregnant women. Correlations with the anthropometrical measures and bone health status in their infants were studied. Bone health was evaluated using QUS with the measurements of speed of sound (SOS, in m/s) and Z score on the right tibia.

RESULTS

There was no significant association between maternal 25OHD and newborn's anthropometrical measures at birth (weight p=0.35, length p=0.59 and head circumference p=0.47). There was a significant negative correlation between a maternal serum adiponectin and a) weight of infants at birth (R= -0.37, p=0.002); b) birth length (R= -0.31, p=0.008) and c) head circumference (R= -0.29, p=0.014). There was no significant correlation between maternal 25OHD blood levels during pregnancy and SOS in newborns (p=0.48). Additionally, a correlation between maternal adiponectin concentration during pregnancy and SOS in newborns was not significant (p=0.82).

CONCLUSION

Although a high prevalence of low 25OHD level among pregnant women was found, maternal vitamin D status did not influence growth and bone health of their offspring at birth. Maternal adiponectin levels in plasma showed an inverse relationship with anthropometrical measures of infants at birth, while no correlation with the newborn's bone health was found.

Reduced Maternal Serum Total, Free and Bioavailable Vitamin D Levels and its Association with the Risk for Postpartum Depressive Symptoms

BACKGROUND

Low vitamin D levels have been implicated in postpartum depressive disorders. However, studies on bioavailable vitamin D levels in postpartum depression are limited. Our study aimed to assess the serum concentrations of total, free and bioavailable 25-hydroxyvitamin D (25(OH)D) levels in women with postpartum depressive symptoms (PPD) and the association between 25(OH)D levels and PPD at 6 week post-delivery.

METHODS

In this cross-sectional study, a total of 330 cases and 330 age and BMI matched controls were recruited from the tertiary care hospital in South India. Women with depressive symptoms were assessed using the validated Edinburg Postnatal Depression Scale (EPDS) and cut-off score ≥10 was used. Serum 25(OH)D and VDBP levels were measured using commercially available ELISA kits.

RESULTS

Serum total, free and bioavailable 25(OH)D levels were significantly lower in postpartum depressive women compared to non-depressive women (p <0.001, p = 0.01). A significant negative correlation was observed between 25(OH)D, free 25(OH)D and bioavailable 25(OH)D with EPDS score in total study subjects (p <0.001, r = -0.19; p <0.001, r = -0.14 and p <0.001, r = -0.14). Multivariate linear regression analysis further confirmed a significant association between serum total, free and bioavailable 25(OH)D levels and EPDS score (p <0.001∗).

CONCLUSIONS

Our study demonstrated that lower serum total, free and bioavailable 25(OH)D levels were associated with postpartum depressive symptoms. Hypovitaminosis D after delivery may be a risk factor for postpartum depression.

Circulating vitamin D and the risk of gestational diabetes: a systematic review and dose-response meta-analysis

PURPOSE

Several meta-analyses of observational studies revealed a modest increase in the risk of gestational diabetes (GDM) among pregnant women with low levels of serum vitamin D. However, no study examined a dose-response meta-analysis as well as a high versus low analysis in this regard.

METHODS

We systematically searched PubMed, Embase, ISI Web of Science, and Scopus up to August 2019 to find prospective observational studies investigating the association of serum 25(OH)D with the risk of developing GDM. Using a random-effects model, the reported risk estimates were pooled.

RESULTS

Nine cohort studies and six nested case-control studies were included in the final analysis (40,788 participants and 1848 cases). Considering linear analysis, each 10 nmol/L increase in circulating 25(OH)D was associated with a 2% lower risk of GDM (effect size (ES): 0.98; 95% CI: 0.98, 0.99; I² = 85.0%, P < 0.001). highest compared with the lowest category of circulating 25(OH)D was associated with a 29% lower risk of GDM, with low evidence of heterogeneity (I² = 45.0%, P = 0.079).

CONCLUSIONS

In conclusion, lower levels of serum 25(OH)D were associated with a higher chance of GDM. Differential results existed between the overall and subgroup analysis, either based on vitamin D detection methods or based on maternal age, although these subgroups partially lowered the heterogeneity.

Gestational vitamin D deficiency causes placental insufficiency and fetal intrauterine growth restriction partially through inducing placental inflammation

Several epidemiological studies suggest an association between vitamin D deficiency (VDD) and fetal intrauterine growth restriction (IUGR). Here, we explored the mechanism through which VDD induced fetal IUGR. Pregnant mice were fed with VDD diet to establish VDD model. Cyp27b1^+/- mice were generated to develop a model of active vitamin D3 deficiency. Cyp27b1^+/- mice were injected with either 1α,25(OH)₂D₃ or vehicle once a day throughout pregnancy. As expected, fetal weight and crown-rump length were reduced in VDD diet-fed mice. Correspondingly, fetal weight and crown-rump length were lower in cyp27b1^+/- mice. 1α,25(OH)₂D₃ elevated fetal weight and crown-rump length, and protected cyp27b1^+/- mice from fetal IUGR. Further analysis found that placental proliferation was inhibited and placental weight was decreased in VDD diet-fed mice. Several growth factors and nutrient transfer pumps were downregulated in the placentas of VDD diet-fed mice. Mechanistically, several inflammatory cytokines were upregulated and placental NF-κB was activated not only in VDD diet-fed mice but also in VDD pregnant women. Interestingly, 1α,25(OH)₂D₃ inhibited the downregulated of placental nutrient transfer pumps and the upregulated of placental inflammatory cytokines in Cyp27b1+/- mice. These results provide experimental evidence that gestational VDD causes placental insufficiency and fetal IUGR may be through inducing placental inflammation.

Maternal Vitamin D Levels During Pregnancy and Their Effects on Maternal-Fetal Outcomes: A Systematic Review

To synthesize and critically review the current evidence available on maternal vitamin D deficiency and its effects on maternal-fetal outcomes, this study reviewed the maternal-fetal outcomes, including prolonged labour or cesarean delivery, preeclampsia, gestational diabetes, low birth weight and small for gestational age, and preterm birth. An extensive systematic searched was performed in Medline and EMBASE, where a medical subject heading (MeSH) was used with terms "Vitamin D/25(OH)D" and "pregnancy/fetal outcomes"; these terms were combined with "and." In Web of Science and Google Scholar, a key word search was used. Nineteen articles were included for full review. This review found that the current state of the evidence is equivocal for maternal-fetal outcomes such as the risk of prolonged labour and cesarean delivery, gestational diabetes, low birth weight and small for gestational age, and preterm birth. Although some previous studies have found improvement in pregnancy outcomes with sufficient vitamin D levels, others have not shown any association with the aforementioned outcomes. This systematic review also highlights an association between the risk of preeclampsia and maternal vitamin D levels that is found to be consistent among studies.

Serum Vitamin D levels and gestational diabetes mellitus: analysis of early pregnancy cohort from a teaching hospital of Kashmir Valley

Background and Aims:

The association of gestational diabetes mellitus and serum Vitamin D levels in different trimesters of pregnancy has been studied recently. We conducted this study in an prospective observational cohort of well-characterized healthy pregnant women to examine the relationship between 1^st trimester Vitamin D levels and Gestational Diabetes Mellitus (GDM) status during pregnancy.

Methods:

All pregnant women attending the out-patient department of Gynecology & Obstetrics, aged less than 35 years, and who were in their first trimester were included in the study. Socio-demographic, anthropometric details, clinical details, food frequency questionnaire and physical activity data was collected using validated pretested questionnaire.

Results:

The comparison between those with GDM and those with normal glucose levels has been illustrated. Women in the GDM are older than those in the non-GDM group. The women in GDM group were taller, heavier and their BMI was greater than those in the non-GDM group. There were no significant differences in dietary intake at baseline between mothers with GDM and those with normal glucose levels. Further, it was found that Vitamin D concentration of <30 nmol/L was found among higher among those with GDM and the relationship was statistically significant.

Conclusion:

There is an association between maternal Vitamin D deficiency and increased risk for GDM in early pregnancy among Kashmiri women.

The association of fluoride in drinking water with serum calcium, vitamin D and parathyroid hormone in pregnant women and newborn infants

BACKGROUND

Chronic exposure to fluoride in drinking water causes an increase in plasma fluoride levels that is related to a reduction in calcium transport across the renal tubule endoplasmic reticulum and plasma membrane. In the present study, it was hypothesised that varying levels of fluoride present in drinking water are associated with serum levels of calcium and the related hormones vitamin D and parathyroid hormone in pregnant women and newborn infants.

METHODS

This cross-sectional study included two groups based on the fluoride concentration in drinking water. One group was considered low/optimum in which the fluoride concentration in drinking water was <1 ppm, and the other group was considered a high fluoride group with ≥1 ppm fluoride in drinking water. In each group, 90 pregnant women were recruited at the hospital during delivery. The participants were given a questionnaire regarding their medical history, sunshine exposure duration, and supplement use and a food frequency questionnaire (FFQ). Fluoride was measured in drinking water, urine, maternal serum and cord blood. Serum calcium, vitamin D, and parathyroid hormone were measured in a fully automated analyser.

RESULTS

In pregnant women, drinking water that contained fluoride was significantly positively correlated with urine and blood serum. Low mean concentrations of vitamin D and deficient (<10 ng/ml) vitamin D were more prevalent among the high fluoride group irrespective of diet, sunshine exposure and supplementation. Serum calcium and parathyroid hormone (PTH) levels were significantly lower in the high fluoride group than in the low/optimum fluoride group in both pregnant mothers' blood and cord blood.

CONCLUSIONS

Drinking water with high fluoride levels was significantly associated with calcium and the related hormones vitamin D and parathyroid hormone.

Relationships between Total, Free and Bioavailable Vitamin D and Vitamin D Binding Protein in Early Pregnancy with Neonatal Outcomes: A Retrospective Cohort Study

Maternal vitamin D deficiency has been associated with adverse neonatal outcomes, however, existing results are inconsistent. Current data focus on total 25-hydroxyvitamin D (25(OH)D) as the common measure of vitamin D status, while additional measures including vitamin D-binding protein (VDBP) and free and bioavailable metabolites have not been explored in relation to neonatal outcomes. We examined whether VDBP and total, free, and bioavailable vitamin D metabolites in early pregnancy are associated with subsequent neonatal outcomes. In this retrospective analysis of 304 women in early pregnancy (<20 weeks gestation), demographic and anthropometric data were collected and total 25(OH)D (chemiluminescent assay), VDBP (polyclonal enzyme-linked immunosorbent assay (ELISA)) and albumin (automated colorimetry) were measured in bio-banked samples. Free and bioavailable 25(OH)D were calculated using validated formulae. Neonatal outcomes were derived from a medical record database. Higher maternal total and free 25(OH)D concentrations were associated with higher neonatal birthweight (β = 5.05, p = 0.002 and β = 18.06, p = 0.02, respectively), including after adjustment for maternal covariates including age, body mass index (BMI) and ethnicity (all p ≤ 0.04). Higher total 25(OH)D and VDBP concentrations were associated with a lower likelihood of neonatal jaundice (odds ratio [OR] [95%CI] = 0.997 [0.994, 1.000], p = 0.04 and 0.98 [0.96, 0.99], p = 0.03, respectively), but these were attenuated after adjustment for the above maternal covariates (both p = 0.09). Our findings suggest a novel association between free 25(OH)D and neonatal birthweight. Total 25(OH)D concentrations were also associated with birthweight, and both total 25(OH)D and VDBP were associated with jaundice, but the latter were not significant after adjustment. These results suggest a potential link between these metabolites and neonatal outcomes; however, further large-scale prospective studies are warranted.

Early Pregnancy Vitamin D Binding Protein Is Independently Associated with the Development of Gestational Diabetes: A Retrospective Cohort Study

BACKGROUND

Vitamin D-binding protein (VDBP) has been implicated in several adverse pregnancy outcomes either directly or indirectly via influencing the concentrations of biologically active vitamin D metabolites. However, human studies exploring these metabolites in pregnancy remain sparse. Here, we examine whether VDBP and total, free, and bioavailable 25-hydroxyvitamin D (25(OH)D) metabolites in early pregnancy are associated with subsequent adverse pregnancy outcomes.

METHODS

We conducted a retrospective analysis of 304 pregnant women in early pregnancy (<20 weeks gestation). The demographic characteristics, anthropometric data, and total 25(OH)D were measured and plasma or serum samples were collected and bio-banked. Using these samples, we measured VDBP (polyclonal ELISA) and albumin (automated colorimetry), and calculated free and bioavailable 25(OH)D using validated formulae. Pregnancy outcomes were derived from scanned medical records. Regression models were used to analyse the relationships between vitamin D metabolites in early pregnancy and subsequent pregnancy outcomes (gestational diabetes mellitus (GDM), pre-eclampsia, preterm birth), with adjustment for predetermined clinically relevant maternal factors including age, body mass index (BMI), and ethnicity.

RESULTS

Lower VDBP concentrations were associated with higher glucose levels and a greater likelihood of developing GDM at 26-28 weeks gestation (odds ratio [OR] (95% CI) = 0.98 (0.97,0.99), p = 0.015). This finding remained significant after adjustment for maternal covariates including age, BMI, and ethnicity (β = -0.003, p = 0.03). Lower total, free and bioavailable 25(OH)D, but not VDBP, were associated with a shorter length of gestation, but only the relationship with total 25(OH)D remained significant after adjustment for the above maternal covariates (β = 0.02, p = 0.006).

CONCLUSIONS

This is the first study to examine VDBP, and total, free and bioavailable 25(OH)D in relation to pregnancy outcomes in a well characterised multi-ethnic cohort of pregnant women. Our findings show that VDBP and total 25(OH)D are associated with GDM and length of gestation, respectively; however, further investigations using large-scale prospective studies are needed to confirm our findings.

Relationship between vitamin D status in the first trimester of pregnancy and gestational diabetes mellitus - A nested case-control study

BACKGROUND & AIMS

Gestational diabetes mellitus (GDM) is one of the most frequent medical complications during pregnancy. It has been associated with many adverse pregnancy, fetal and neonatal outcomes, as well as with an increased risk for mothers and children in the long term. There is a growing interest in vitamin D and its potential role in the development of metabolic disorders. However, the medical literature is not consensual. The aim of this study was to assess the risk of GDM according to vitamin D status during the first trimester.

METHODS

This study is a nested case-control study performed from a multicenter prospective observational cohort of pregnant women assessed for 25-hydroxyvitamin D levels (25OHD). Three hundred ninety-three patients were included in the initial cohort. After applying exclusion criteria, a total of 1191 pregnant women were included. Two hundred fifty women with GDM (cases) were matched to 941 women without GDM (controls) for parity, age, body mass index before pregnancy, the season of conception, and phototype. This study was funded by a grant from the "Programme Hospitalier de Recherche Publique 2010".

RESULTS

The GDM risk was significantly greater for patients with 25OHD levels <20 ng/mL (OR = 1∙42, 95% CI 1∙06-1∙91; p = 0∙021). However, there was no significant relationship with other thresholds. The study of 25OHD levels with the more precise cutting of 5 units intervals showed a variable relationship with GDM risk, as the risk was low for very low 25OHD levels, increased for moderated levels, decreased for normal levels, and finally increased for higher levels.

CONCLUSION

According to our study, there seems to be no linear relationship between GDM and 25OHD levels in the first trimester of pregnancy since GDM risk does not continuously decrease as 25OHD concentrations increase. Our results most probably highlight the absence of an association between 25OHD levels and GDM risk.

Serum vitamin D deficiency and risk of gestational diabetes mellitus: a meta-analysis

INTRODUCTION

This meta-analysis was performed to confirm the relationship of gestational diabetes mellitus (GDM) and vitamin D.

MATERIAL AND METHODS

PubMed and CNKI databases were searched for relevant articles. Standard mean difference (SMD) along with 95% CI was used to compare vitamin D level between women with GDM and healthy subjects. The correlation coefficient between the vitamin D and homeostasis model assessment-insulin resistance index (HOMA-IR) was analyzed.

RESULTS

The vitamin D level of GDM subjects was much lower than healthy subjects (SMD = -0.71, 95% CI: -0.91, -0.50). Vitamin D deficiency was associated with high risk of GDM (OR = 1.15, 95% CI: 1.07-1.23). Vitamin D was negatively correlated with HOMA-IR (r = -0.62, 95% CI: -0.85, -0.39). The analysis showed no publication bias (Egger's: p = 0.197; Begg's: p = 0.786).

CONCLUSIONS

Vitamin D is closely associated with the onset of GDM.

The association of vitamin D status and supplementation during pregnancy with gestational diabetes mellitus: a Chinese prospective birth cohort study

BACKGROUND

Previous studies have shown conflicting findings regarding the relation of vitamin D status and supplementation during pregnancy with gestational diabetes mellitus (GDM). Most of these studies hypothesized that 25-hydroxyvitamin D [25(OH)D] concentrations were associated with GDM risk and glucose metabolism based on linear association models.

OBJECTIVES

We aimed to estimate the associations of 25(OH)D concentrations and vitamin D supplementation with GDM risk and glucose metabolism and determine the threshold concentrations of 25(OH)D that could significantly affect glucose metabolism and GDM risk.

METHODS

In a prospective birth cohort study, we collected information about sociodemographic characteristics, health status, and lifestyle from 4984 pregnant women. Vitamin D supplementation and 25(OH)D concentrations were assessed in the second trimester. Data from the 75-g oral-glucose-tolerance test were obtained at 24-28 weeks of gestation.

RESULTS

A total of 922 (18.5%) women were diagnosed with GDM. Compared with women with 25(OH)D concentrations <25 nmol/L, the GDM risk was significantly lower in women with 25(OH)D concentrations ranging from 50 to 75 nmol/L (RR: 0.74; 95% CI: 0.58, 0.95) and >75 nmol/L (RR: 0.40; 95% CI: 0.22, 0.70). The curve-fitting models suggested a significant large reduction in GDM risk, fasting plasma glucose, and area under the curve of glucose with increasing 25(OH)D concentrations only for concentrations >50 nmol/L. Consistently, GDM risk was significantly reduced only in women who took 400-600 IU vitamin D/d (RR: 0.83; 95% CI: 0.70, 0.97) with a mean 25(OH)D concentration of 50 nmol/L but not in women taking vitamin D sometimes with a mean 25(OH)D concentration of 40 nmol/L.

CONCLUSIONS

GDM risk was significantly reduced only in pregnant women with 25(OH)D concentrations >50 nmol/L. Pregnant women taking 400-600 IU vitamin D/d with mean 25(OH)D concentrations of 50 nmol/L had a lower risk of GDM.

Vitamin D, and Maternal and Child Health

Vitamin D has important roles in calcium metabolism and in the prevention of rickets and osteomalacia; low levels of 25-hydroxyvitamin D are common in the general population and amongst pregnant women. Whilst there is a wealth of observational evidence linking vitamin D deficiency to a wide range of disease outcomes, there are currently few high-quality randomised controlled trials to confirm any causal associations, although many are currently in progress. Furthermore, currently, the vast majority of published guidelines recommend standard supplemental vitamin D doses for children and pregnant women, yet there is increasing recognition that individual characteristics and genetic factors may influence the response to supplementation. As such, future research needs to concentrate on documenting definite beneficial clinical outcomes of vitamin D supplementation, and establishing personalised dosing schedules and demonstrating effective approaches to optimising initiation and adherence.

Vitamin D status during pregnancy and offspring outcomes: a systematic review and meta-analysis of observational studies

BACKGROUND/OBJECTIVES

Vitamin D deficiency during pregnancy may influence adverse outcomes in offspring. The aim of this systematic review and meta-analysis of observational studies was to assess the association between low prenatal concentrations of 25(OH)D (by using three different cut-off levels), preterm birth (PTB) and anthropometric and neurodevelopmental outcomes in offspring.

SUBJECTS/METHODS

Studies reporting data on the association between maternal vitamin D concentrations and offspring outcomes identified through a systematic review of scientific literature published in PubMed/MEDLINE, Scopus and the Cochrane Library databases up to April 2017.

RESULTS

We included 54 eligible studies. Vitamin D-deficient mothers (<30 nmol/L) had offspring with lower birthweight (MD -87.82 g; 95% CI -119.73, -55.91 g), head circumference (MD -0.19 cm; 95% CI -0.32, -0.06 cm) and a higher risk of small for gestational age (SGA) infants and PTB (OR 1.59; 95% CI 1.24, 2.03) compared to mothers with concentrations ≥30 nmol/L. Vitamin D insufficiency (<50 nmol/L) was associated with a higher risk of SGA and PTB (OR 1.43; 95% CI 1.08, 1.91 and OR 1.28; 95% CI 1.08, 1.52, respectively). Concentrations of 25(OH)D ≥75 nmol/L were not found to be associated with birthweight, SGA or PTB. Offspring of vitamin D-insufficient mothers had lower scores in mental (MD -1.12 points; 95% CI -1.82, -0.42 cm) and language developmental tests (MD -0.35 points; 95% CI -1.00, 0.31 cm).

CONCLUSION

Maternal vitamin D deficiency is associated with offspring adverse anthropometric outcomes and PTB; insufficiency with a higher risk of SGA, PTB and adverse neurodevelopmental outcomes.

Significance of Vitamin D on the Susceptibility of Gestational Diabetes Mellitus - A Meta-Analysis

Vitamin D plays an important role in glucose tolerance by stimulating insulin secretion and evidences suggest a contradictory result on the association between vitamin D status and risk of developing gestational diabetes mellitus (GDM). The present updated meta-analysis has been undertaken to find out the joined effect of vitamin D status on the risk of effect GDM considering previously published articles. Data were collected through literature search using electronic databases to retrieve relevant published research articles using various combinations of the following keywords, "vitamin D," "vitamin D deficiency," "cholecalciferol," "25-hydroxyvitamin D," "25(OH) D," "gestational diabetes mellitus," and "GDM." A total of 36 studies including 7,596 GDM cases and 23,377 non-GDM controls were involved in this study. Overall, pooled meta-analysis showed that pregnant women diagnosed with GDM have 18% higher risk of GDM risk when compared with controls [odds ratio (OR) = 1.18, 95% confidence interval (CI) 1.10-1.25; P = 0.00] with high heterogeneity (I² = 73.29). The mean difference was also significantly different between cases and controls (OR = -0.18, 95% CI - 0.22 to - 0.14; P = 0.00). Subgroup analysis showed significant results with age more than 30 years, Asian and European regions, and case-control, cross-sectional, and nested case-control study design. Low concentration of vitamin D is associated with the development of GDM. Although in future more studies especially systematically designed clinical trials based on vitamin D supplementation with large sample size on different population are needed to elucidate the exact concentration of vitamin D during pregnancy as well as before and after pregnancy.

Relationship of Early Vitamin D Concentrations and Gestational Diabetes Mellitus in Indian Pregnant Women

Background: A high prevalence of vitamin D deficiency exists in pregnant Indian women (~90%). Increasing evidence suggests that vitamin D could play a pivotal role in maintaining normal glucose homeostasis. We aimed to determine the association between maternal vitamin D concentrations in early pregnancy and the risk of gestational diabetes mellitus (GDM). Methods: A prospective observational study was conducted on healthy pregnant women (n = 392) attending routine antenatal care at St. John's Medical College Hospital, Bangalore recruited at ~12 weeks of gestation. At baseline, details on socio-economic status, obstetric history, dietary intakes, and anthropometry were collected. Venous plasma total vitamin D concentration was assessed using tandem liquid chromatography mass spectrophotometry (LC-MS/MS). Oral glucose tolerance test (OGTT) at recruitment, followed by glucose tolerance test (GTT) at mid-pregnancy was conducted. GDM was diagnosed and confirmed using the International Association of Diabetes and Pregnancy Study Groups (IADPSG) classification. Univariate and adjusted logistic regression models were used to evaluate the associations between total vitamin D concentrations at enrollment with GDM. Results: Of the cohort, 10.2% were diagnosed as GDM. Women with GDM were older (26 vs. 24 years) and heavier (51.6 vs. 51.2 kg) compared to the rest. A higher prevalence of GDM was observed among women with 1st trimester plasma total vitamin D in the lowest quartile (≤23.6 nmol/L) compared to the subjects in the other three quartiles (16.1 vs. 8.6%, p = 0.033). Adjusted multivariable regression analysis showed that women in the lowest quartile of plasma total vitamin D had twice the odds of GDM compared to women belonging to the remaining quartiles [OR = 2.32 (95%CI: 1.10, 4.91), p = 0.028]. Conclusions: Low plasma total vitamin D concentrations in early pregnancy may be associated with a higher risk of GDM.

Vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D supplementation during pregnancy may be needed to protect against adverse pregnancy outcomes. This is an update of a review that was first published in 2012 and then in 2016.

OBJECTIVES

To examine whether vitamin D supplementation alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register (12 July 2018), contacted relevant organisations (15 May 2018), reference lists of retrieved trials and registries at clinicaltrials.gov and WHO International Clinical Trials Registry Platform (12 July 2018). Abstracts were included if they had enough information to extract the data.

SELECTION CRITERIA

Randomised and quasi-randomised trials evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy in comparison to placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently i) assessed the eligibility of trials against the inclusion criteria, ii) extracted data from included trials, and iii) assessed the risk of bias of the included trials. The certainty of the evidence was assessed using the GRADE approach.

MAIN RESULTS

We included 30 trials (7033 women), excluded 60 trials, identified six as ongoing/unpublished trials and two trials are awaiting assessments.Supplementation with vitamin D alone versus placebo/no interventionA total of 22 trials involving 3725 pregnant women were included in this comparison; 19 trials were assessed as having low-to-moderate risk of bias for most domains and three trials were assessed as having high risk of bias for most domains. Supplementation with vitamin D alone during pregnancy probably reduces the risk of pre-eclampsia (risk ratio (RR) 0.48, 95% confidence interval (CI) 0.30 to 0.79; 4 trials, 499 women, moderate-certainty evidence) and gestational diabetes (RR 0.51, 95% CI 0.27 to 0.97; 4 trials, 446 women, moderate-certainty evidence); and probably reduces the risk of having a baby with low birthweight (less than 2500 g) (RR 0.55, 95% CI 0.35 to 0.87; 5 trials, 697 women, moderate-certainty evidence) compared to women who received placebo or no intervention. Vitamin D supplementation may make little or no difference in the risk of having a preterm birth < 37 weeks compared to no intervention or placebo (RR 0.66, 95% CI 0.34 to 1.30; 7 trials, 1640 women, low-certainty evidence). In terms of maternal adverse events, vitamin D supplementation may reduce the risk of severe postpartum haemorrhage (RR 0.68, 95% CI 0.51 to 0.91; 1 trial, 1134 women, low-certainty evidence). There were no cases of hypercalcaemia (1 trial, 1134 women, low-certainty evidence), and we are very uncertain as to whether vitamin D increases or decreases the risk of nephritic syndrome (RR 0.17, 95% CI 0.01 to 4.06; 1 trial, 135 women, very low-certainty evidence). However, given the scarcity of data in general for maternal adverse events, no firm conclusions can be drawn.Supplementation with vitamin D and calcium versus placebo/no interventionNine trials involving 1916 pregnant women were included in this comparison; three trials were assessed as having low risk of bias for allocation and blinding, four trials were assessed as having high risk of bias and two had some components having a low risk, high risk, or unclear risk. Supplementation with vitamin D and calcium during pregnancy probably reduces the risk of pre-eclampsia (RR 0.50, 95% CI 0.32 to 0.78; 4 trials, 1174 women, moderate-certainty evidence). The effect of the intervention is uncertain on gestational diabetes (RR 0.33,% CI 0.01 to 7.84; 1 trial, 54 women, very low-certainty evidence); and low birthweight (less than 2500 g) (RR 0.68, 95% CI 0.10 to 4.55; 2 trials, 110 women, very low-certainty evidence) compared to women who received placebo or no intervention. Supplementation with vitamin D and calcium during pregnancy may increase the risk of preterm birth < 37 weeks in comparison to women who received placebo or no intervention (RR 1.52, 95% CI 1.01 to 2.28; 5 trials, 942 women, low-certainty evidence). No trial in this comparison reported on maternal adverse events.Supplementation with vitamin D + calcium + other vitamins and minerals versus calcium + other vitamins and minerals (but no vitamin D)One trial in 1300 participants was included in this comparison; it was assessed as having low risk of bias. Pre-eclampsia was not assessed. Supplementation with vitamin D + other nutrients may make little or no difference in the risk of preterm birth < 37 weeks (RR 1.04, 95% CI 0.68 to 1.59; 1 trial, 1298 women, low-certainty evidence); or low birthweight (less than 2500 g) (RR 1.12, 95% CI 0.82 to 1.51; 1 trial, 1298 women, low-certainty evidence). It is unclear whether it makes any difference to the risk of gestational diabetes (RR 0.42, 95% CI 0.10 to 1.73) or maternal adverse events (hypercalcaemia no events; hypercalciuria RR 0.25, 95% CI 0.02 to 3.97; 1 trial, 1298 women,) because the certainty of the evidence for both outcomes was found to be very low.

AUTHORS' CONCLUSIONS

We included 30 trials (7033 women) across three separate comparisons. Our GRADE assessments ranged from moderate to very low, with downgrading decisions based on limitations in study design, imprecision and indirectness.Supplementing pregnant women with vitamin D alone probably reduces the risk of pre-eclampsia, gestational diabetes, low birthweight and may reduce the risk of severe postpartum haemorrhage. It may make little or no difference in the risk of having a preterm birth < 37 weeks' gestation. Supplementing pregnant women with vitamin D and calcium probably reduces the risk of pre-eclampsia but may increase the risk of preterm births < 37 weeks (these findings warrant further research). Supplementing pregnant women with vitamin D and other nutrients may make little or no difference in the risk of preterm birth < 37 weeks' gestation or low birthweight (less than 2500 g). Additional rigorous high quality and larger randomised trials are required to evaluate the effects of vitamin D supplementation in pregnancy, particularly in relation to the risk of maternal adverse events.

Cord blood vitamin D status is associated with cord blood insulin and c-peptide in two cohorts of mother-newborn pairs

CONTEXT

Vitamin D may be important for prenatal programming of insulin and glucose regulation, but maternal vitamin D deficiency during pregnancy is common.

OBJECTIVE

We examined associations of early vitamin D status with markers of fetal insulin secretion (cord blood insulin and c-peptide). We hypothesized that maternal 25-hydroxyvitamin D (25(OH)D) during pregnancy and cord blood 25(OH)D would both be positively associated with cord blood insulin and c-peptide.

METHODS

We studied mother-newborn pairs from two cohorts: Project Viva (862 pairs included) and Genetics of Glucose Regulation in Gestation and Growth (Gen3G, 660 pairs included). We analyzed associations of the cord blood hormones with maternal 25(OH)D using generalized additive models with nonlinear spline terms and with cord blood 25(OH)D using multivariable linear regression models.

RESULTS

25(OH)D levels were <75 nmol/L in over 70% of mothers and 85% of newborns. Maternal and cord blood 25(OH)D levels were correlated: r=0.58 in Project Viva and 0.37 in Gen3G. Maternal 25(OH)D had an inverted U-shaped relationship with cord blood insulin and c-peptide in both cohorts. Cord blood 25(OH)D had a linear relationship with the cord blood hormones. In fully adjusted models, each 10-nmol/L increase in cord blood 25(OH)D was associated with higher cord blood insulin and c-peptide concentrations: 3.7% (95% CI: (0.09, 7.5) and 3.2% (95% CI: 0.8, 5.6), respectively in Project Viva; 2.2% (95% CI: -0.1, 4.6) and 3.6% (95% CI: 1.0, 6.3), respectively in Gen3G.

CONCLUSIONS

Vitamin D may play a role in regulating fetal insulin secretion, potentially impacting glucose regulation and growth.

Severe 25(OH)vitamin-D deficiency: A risk factor for development of gestational diabetes mellitus

OBJECTIVE

To estimate the level of 25 (OH)vitamin D in gestational diabetes mellitus (GDM) and to find the correlation between level of 25(OH)vitamin D and GDM.

MATERIALS AND METHODS

The study was conducted on 50 diagnosed patients of GDM attending antenatal clinic in the obstetrics and gynecology department of Pt. B.D. Sharma PGIMS, Rohtak. 50 age and gestational age matched normoglycemic women were taken as control group. Procedure of study was explained to the participants and informed consent was taken.

RESULTS

GDM women had higher age, BMI, and positive family history of type 2 DM as compared to pregnant women without GDM. The mean vitamin D in GDM women was 32.64 ± 24.33 nmol/L while in controls it was 39.90 ± 21.86 nmol/L(P = 0.033). The prevalence of severe vitamin D deficiency(<25 nmol/L) was found to be 44% among GDM women (22 out of 50 GDM women) and 20% among women with normoglycemia (10 out of 50 normoglycemic controls) with significant p value of 0.010 and odds ratio of 1.833. GDM women with BMI>25 kg/m² had 1.799 times chances to be severely deficit in vitamin D than women with BMI<25 kg/m² 6 GDM women had mild vitamin D deficiency (>50 but <75 nmol/L) and 16 had moderate deficiency (>25 but <50 nmol/L). Only 6 GDM patients were found to be sufficient for vitamin D(>75 nmol/L).

CONCLUSION

Severe vitamin D deficiency in second trimester of pregnancy is significantly associated with elevated risk for GDM.

Studying the relation between vitamin D deficiency and glycemic state among pregnant women with gestational diabetes

AIM

This study was conducted to illustrate the relation between vitamin D deficiency and glycemic parameters.

MATERIALS AND METHODS

The study was carried out on 80 pregnant females who were attending obstetrics and gynecology out-patient clinic in el-Shatby hospital in Alexandria university, Egypt. They were divided into 2 groups: group 1 (n = 40) pregnant females diagnosed with gestational diabetes de novo at week 24-28 and group 2 (n = 40) pregnant females of the same age group who were not suffering from any glucose intolerance (control group). Each patient was subjected to detailed history taking, complete physical examination, One step 75 gm Oral glucose tolerance test, insulin, glycated hemoglobin(HbA1c),homeostatic model assessment of insulin resistance(HOMA-IR), 25 hydroxy-vitamin D, serum calcium, phosphorous and parathormone were assessed.

RESULTS

A statistically significant higher fasting blood glucose (FBG), HbA1c%, fasting insulin and HOMA-IR was observed in patients with Gestational diabetes mellitus (GDM) versus control (p < 0.001). However, no significant difference was observed as regards Vitamin D levels in patients with GDM and control group. Among patients with GDM, vitamin D was found to correlate negatively with HbA1c (p < 0.001), insulin(p = 0.019) and HOMA-IR(p = 0.034).

CONCLUSION

No definite causal relationship was observed between low vitamin D and subsequent occurrence of GDM.however, a significant correlation was found between the degree of vitamin D deficiency and the insulin resistance in patients with GDM.

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

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

Disparities in the timing and measurement methods to assess vitamin D status during pregnancy: A Narrative Review

Studies that examined associations between low circulating 25-hydroxyvitamin D (25(OH)D) and adverse pregnancy outcomes used various designs, assay methods and time points for measurement of 25(OH)D concentrations, which creates some confusion in the current literature. We aimed to investigate the variability in the timing and measurement methods used to evaluate vitamin D status during pregnancy. Analysis of 198 studies published between 1976 and 2017 showed an important variability in the choice of 1) threshold values for 25(OH)D insufficiency or deficiency, 2) 25(OH)D measurement methods, and 3) trimester in which 25(OH)D concentrations were measured. Blood samples were taken once during pregnancy in a large majority of studies, which may not be representative of vitamin D status throughout pregnancy. Most studies reported adjustment for confounding factors including season of blood sampling, but very few studies used the 25(OH)D gold standard assay, the LC-MS/MS. Prospective studies assessing maternal 25(OH)D concentrations 1) by standardized and validated methods, 2) at various time points during pregnancy, and 3) after considering potential confounding factors, are needed.

Histone H3 lysine 9 acetylation is downregulated in GDM Placentas and Calcitriol supplementation enhanced this effect

Despite the ever-rising incidence of Gestational Diabetes Mellitus (GDM) and its implications for long-term health of mothers and offspring, the underlying molecular mechanisms remain to be elucidated. To contribute to this, the present study's objectives are to conduct a sex-specific analysis of active histone modifications in placentas affected by GDM and to investigate the effect of calcitriol on trophoblast cell's transcriptional status. The expression of Histone H3 lysine 9 acetylation (H3K9ac) and Histone H3 lysine 4 trimethylation (H3K4me3) was evaluated in 40 control and 40 GDM (20 male and 20 female each) placentas using immunohistochemistry and immunofluorescence. The choriocarcinoma cell line BeWo and primary human villous trophoblast cells were treated with calcitriol (48 h). Thereafter, western blots were used to quantify concentrations of H3K9ac and the transcription factor FOXO1. H3K9ac expression was downregulated in GDM placentas, while H3K4me3 expression was not significantly different. Cell culture experiments showed a slight downregulation of H3K9ac after calcitriol stimulation at the highest concentration. FOXO1 expression showed a dose-dependent increase. Our data supports previous research suggesting that epigenetic dysregulations play a key role in gestational diabetes mellitus. Insufficient transcriptional activity may be part of its pathophysiology and this cannot be rescued by calcitriol.

Association of Vitamin D and Parathyroid Hormone with Insulin Sensitivity, Beta Cell Function and Gestational Diabetes in Pregnancy: A Cross-Sectional, Observational Study

INTRODUCTION

Vitamin D (25OHD) and parathyroid hormone (PTH) are associated with dysglycemia, and we investigated them in gestational diabetes mellitus (GDM).

METHODS

In this cross-sectional, observational study, we included 75 pregnant women between 24 and 28 weeks of gestation. A fasting venous sample was collected for plasma glucose (FPG), insulin, PTH and 25OHD. Glucose and insulin samples were collected hourly after 75 g glucose load for 2 h. Insulin sensitivity was estimated by the Matsuda index (MI) and beta cell function by the insulin secretion sensitivity index (ISSI-2). The subjects were stratified into three groups and tertiles according to the 25OHD and PTH, respectively. Appropriate statistical tests were used to compare the MI, ISSI-2 and GDM among the groups.

RESULTS

GDM was seen in 14/75, and of these patients, 2 were 25OHD deficient, 7 insufficient and 5 had sufficient 25OHD. MI and ISSI-2, though not correlated with the 25OHD, decreased from the lower to higher PTH tertile (P < 0.001). FPG, AUCgluc (area under the curve glucose) and prevalence of GDM increased from the lower to higher PTH tertile (P < 0.001).

CONCLUSION

Increased PTH was associated with decreased insulin sensitivity, beta cell function and GDM in pregnancy, irrespective of the underlying 25OHD level.

The Association of Vitamin D Levels with Common Pregnancy Complications

The association between vitamin D deficiency and various adverse pregnancy outcomes has been extensively investigated in recent years. The pregnant woman is the only source of vitamin D for the foetus. The main sources of vitamin D for pregnant women are sunlight, fortified dairy products, oily fish and dietary supplements. Vitamin D deficiency during pregnancy has been associated with some adverse neonatal outcomes as well as an increased risk of late pregnancy complications. The outcomes of the published studies investigating preeclampsia and gestational diabetes mellitus vary with some large trials suggesting a potential positive effect of vitamin D supplementation during pregnancy on the decreased risk of these complications. Research also suggests a possible connection between lower vitamin D concentrations and increased risk of preterm labour. In our manuscript, we aim to review the existing literature regarding the prevalence of vitamin D deficiency during pregnancy, the factors associated with vitamin D deficiency, and possible pregnancy complications arising from it.

Association between maternal mid-gestation vitamin D status and neonatal abdominal adiposity

OBJECTIVES

Lower vitamin D status has been associated with adiposity in children through adults. However, the evidence of the impact of maternal vitamin-D status during pregnancy on offspring's adiposity is mixed. The objective of this study was to examine the associations between maternal vitamin-D [25(OH)D] status at mid-gestation and neonatal abdominal adipose tissue (AAT) compartments, particularly the deep subcutaneous adipose tissue linked with metabolic risk.

METHODS

Participants (N = 292) were Asian mother-neonate pairs from the mother-offspring cohort, Growing Up in Singapore Towards healthy Outcomes. Neonates born at ≥34 weeks gestation with birth weight ≥2000 g had magnetic resonance imaging (MRI) within 2-weeks post-delivery. Maternal plasma glucose using an oral glucose tolerance test and 25(OH)D concentrations were measured. 25(OH)D status was categorized into inadequate (≤75.0 nmol/L) and sufficient (>75.0 nmol/L) groups. Neonatal AAT was classified into superficial (sSAT), deep subcutaneous (dSAT), and internal (IAT) adipose tissue compartments.

RESULTS

Inverse linear correlations were observed between maternal 25(OH)D and both sSAT (r = -0.190, P = 0.001) and dSAT (r = -0.206, P < 0.001). Each 1 nmol/L increase in 25(OH)D was significantly associated with reductions in sSAT (β = -0.14 (95% CI: -0.24, -0.04) ml, P = 0.006) and dSAT (β = -0.04 (-0.06, -0.01) ml, P = 0.006). Compared to neonates of mothers with 25(OH)D sufficiency, neonates with maternal 25(OH)D inadequacy had higher sSAT (7.3 (2.1, 12.4) ml, P = 0.006), and dSAT (2.0 (0.6, 3.4) ml, P = 0.005) volumes, despite similar birth weight. In the subset of mothers without gestational diabetes, neonatal dSAT was also greater (1.7 (0.3, 3.1) ml, P = 0.019) in neonates with maternal 25(OH)-inadequacy. The associations with sSAT and dSAT persisted even after accounting for maternal glycemia (fasting and 2-h plasma glucose).

CONCLUSIONS

Neonates of Asian mothers with mid-gestation 25(OH)D inadequacy have a higher abdominal subcutaneous adipose tissue volume, especially dSAT (which is metabolically similar to visceral adipose tissue in adults), even after accounting for maternal glucose levels in pregnancy.

Maternal vitamin D supplementation during pregnancy

Introduction

Maternal vitamin D status in pregnancy has been linked to many health outcomes in mother and offspring. A wealth of observational studies have reported on both obstetric outcomes and complications, including pre-eclampsia, gestational diabetes, mode and timing of delivery. Many foetal and childhood outcomes are also linked to vitamin D status, including measures of foetal size, body composition and skeletal mineralization, in addition to later childhood outcomes, such as asthma.

Sources of data

Synthesis of systematic and narrative reviews.

Areas of agreement and controversy

The findings are generally inconsistent in most areas, and, at present, there is a lack of data from high-quality intervention studies to confirm a causal role for vitamin D in these outcomes. In most areas, the evidence tends towards maternal vitamin D being of overall benefit, but often does not reach statistical significance in meta-analyses.

Growing points and areas timely for developing research

The most conclusive evidence is in the role of maternal vitamin D supplementation in the prevention of neonatal hypocalcaemia; as a consequence the UK department of health recommends that pregnant women take 400 IU vitamin D daily. High-quality randomized placebo-controlled trials, such as the UK-based MAVIDOS trial, will inform the potential efficacy and safety of vitamin D supplementation in pregnancy across a variety of outcomes.

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.

Effect of vitamin D3 supplementation in pregnancy on risk of pre-eclampsia - Randomized controlled trial

BACKGROUND

Vitamin D plays pivotal role in decidualization and implantation of the placenta. Recent researches have shown that low level of vitamin D3 "25-hydroxyvitamin D (25[OH]D)" in serum is a risk factor for pre-eclampsia. Latest evidence supports role of vitamin D3 deficiency treatment in reducing the risk of pre-eclampsia. The aim of this study is to determine the effect of antenatal supplementation of vitamin D3 on the risk of pre-eclampsia and to explore the dose effect in attaining the vitamin D3 normal level.

METHOD

An open labelled randomized controlled study was conducted on 179 pregnant women presenting in King Fahad Medical City antenatal clinic from Oct 2012-Oct 2015. Patients with age less than 20 years or more than 40 years, pregnancy with fetal anomalies, history of hypertension, pre-eclampsia, recurrent miscarriage, chronic renal or hepatic disease and malignancy were excluded from the study. Serum 25[OH]D was analysed during the first trimester (between 6 and 12 weeks of pregnancy). Patients with vitamin D3 deficiency (serum levels <25 nmol/L) were included in the study and randomized for vitamin D3 supplementation 400 IU (Group 1) versus 4000 IU (Group 2). Both groups were compared for the prevalence of pre-eclampsia and dose effect on vitamin D level.

RESULTS

Of 179 gravidae enrolled, 164 completed the trial. Mean maternal 25[OH]D was significantly increased in group 2 from 16.3 ± 5 nmol/mL to 72.3 ± 30.9 nmol/mL compared with group 1 from 17.5 ± 6.7 nmol/mL to 35.3 ± 20.7 nmol/mL (p > 0.0001). The relative risk reduction (RRR) for attaining ≥75 nmol/L before delivery was significantly higher (RRR 93.2 [CI 79-98] when treated with 4000 IU. The total incidence of pre-eclampsia in the study population was 4.3%. In comparison to group 1, the group 2 reported fewer pre-eclampsia events during the study period (8.6% versus 1.2%; p < 0.05). The total number of IUGRs was lesser in the group 2 (9.6%) versus group 1 (22.2%); p = 0.027. However, other obstetric outcomes were comparable between both groups.

CONCLUSION

Vitamin D supplementation in the deficient group reduces the risk of pre-eclampsia and IUGR in a dose dependant manner. However larger clinical trials are essential to investigate optimum dosage of vitamin D3 in this group.

Maternal Early Pregnancy Plasma Concentration of 25-Hydroxyvitamin D and Risk of Gestational Diabetes Mellitus

We examined whether 25-Hydroxyvitamin D [25(OH) D] concentrations, measured at the first prenatal visit, would be associated with risk of gestational diabetes mellitus (GDM). From July 2015 to June 2016, consecutive women who admitted to the two-obstetrics center in china were included. Relevant data were collected between 24 and 28 weeks of gestation, including fasting plasma glucose (FPG) and 25(OH) D concentrations at the first prenatal visit and the one-step GDM screened with 75-g oral glucose tolerance test (OGTT). Blood from women at first prenatal visit was available for 827 women and 101 of them developed GDM (12.2%). The GDM distribution across the 25(OH) D quartiles ranged between 3.9% (fourth quartile, Q4) and 26.1% (first quartile, Q1). The median plasma concentration of 25(OH) D at first prenatal visit was significantly lower in women who developed GDM compared with those not developed (p < 0.001). In multivariate models comparing the 25(OH) D of Q1, second (Q2) and third quartiles (Q3) against the Q4, it observed that concentrations of 25(OH) D in Q1 and Q2 were associated with later developed GDM, and risk of GDM was increased by 240 and 48%, respectively. The women group with combined vitamin D deficiency and obesity had an OR of 4.66 [95% CI (2.91-8.15); p < 0.001] for GDM compared to those without vitamin D deficiency and obesity. Low 25(OH) D concentrations at the first prenatal visit were associated with increased risk of GDM and might be useful in identifying women at risk of GDM for performing early prevention strategies.