Effects of vitamin D supplementation during pregnancy on neonatal vitamin D and calcium concentrations: a systematic review and meta-analysis

Associations of ambient temperature and total cloud cover during pregnancy with newborn vitamin D status

OBJECTIVES

We aimed to estimate the effects of temperature and total cloud cover before birth on newborn vitamin D status.

STUDY DESIGN

Prospective birth cohort.

METHODS

This study included 2055 mother-newborn pairs in Wuhan, Hubei province, China. The data of temperature and total cloud cover from 30 days before birth were collected, and cord blood 25-hydroxyvitamin D [25(OH)D] were determined. Restricted cubic spline regression models, multiple linear regression models, and logistic regression models were applied to estimate the associations.

RESULTS

A "J" shaped curve was observed between temperature and vitamin D status, and an inverse "J" shaped curve was observed between total cloud cover and vitamin D status. Compared to the fourth quartile (75-100th percentile, Q4) of average temperature (30 days before birth), the odds ratio (OR) for Q1 (0-25th percentile) associated with the vitamin D deficiency occurrence (<20 ng/mL) was 3.63 (95% CI, 1.54, 8.65). Compared to Q1 of the average total cloud cover (30 days before birth), the OR associated with the occurrence of vitamin D deficiency was 2.38 (95% CI, 1.63, 3.50) for the Q4.

CONCLUSIONS

Low temperature and high cloud cover before delivery were significantly associated with an increased probability of vitamin D deficiency in newborns. The findings suggested that pregnancy women lacking sufficient sunlight exposure still need vitamin D supplement to overcome the potential vitamin D deficiency status.

Early pregnancy vitamin D status and risk of select congenital anomalies in the National Birth Defects Prevention Study

INTRODUCTION

Vitamin D deficiency is associated with adverse pregnancy events. However, its role in the etiology of congenital anomalies remains unclear. We examined the association between vitamin D status, measured through prepregnancy diet, UV exposure, season of conception, and congenital anomalies.

METHODS

We used data from the National Birth Defects Prevention Study, a U.S. population-based case-control study (1997-2011). Prepregnancy dietary vitamin D was calculated from food frequency questionnaires and evaluated using tertiles, based on the distribution in controls. We used the National Oceanic and Atmospheric Administration Weather Service to assign UV indices based on location and estimated date of conception, then dichotomized UV exposure (low vs. high). Seasons of conception was categorized as fall/winter spring/summer. We used logistic regression to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI).

RESULTS

Lower prepregnancy dietary vitamin D intake (<65.21 IU/d vs. >107.55 IU/d) was associated with increased odds of anencephaly (aOR = 1.28, 95% CI 1.01, 1.63), hypospadias (aOR = 1.21, 95% CI 1.04, 1.40), septal defects (aOR = 1.16, 95% CI 1.05, 1.30), diaphragmatic hernia (aOR = 1.42, 95% CI 1.13, 1.79), and gastroschisis (aOR = 1.27, 95% CI 1.07, 1.52). Findings were consistent when we stratified by UV exposure and season of conception.

CONCLUSIONS

Our findings suggest lower dietary intake of vitamin D may be associated with increased risk of select congenital anomalies. Further investigations are warranted to evaluate the effects of other nutrients and appropriate thresholds and sources of vitamin D using serum.

Lag associations of gestational phthalate exposure with maternal serum vitamin D levels: Repeated measure analysis

Few studies have investigated the relationships between gestational phthalate exposure and maternal circulating vitamin D. In the Ma'anshan birth cohort, 3265 pregnant women were included. Each woman provided up to three urine and serum samples for measurement of phthalates and 25(OH)D and calcium, respectively. Linear mixed models were performed to analyse the association between phthalate metabolites and 25(OH)D and calcium. Stratified analyses of the relationship between phthalates and 25(OH)D by urine collection season were conducted. Finally, the post hoc lag effect of phthalate exposure on 25(OH)D was determined if longitudinal associations were significant. Some phthalate metabolites were associated with increased 25(OH)D but with decreased calcium. Furthermore, the relationship of phthalate exposure with 25(OH)D varied with urine collection season. Phthalate metabolites collected in summer and autumn were associated with an increase in 25(OH)D, while monobenzyl phthalate collected in winter and spring was inversely associated with 25(OH)D. Finally, high-molecular-weight phthalates had lag associations with 25(OH)D with a 1-trimester lag period. Low-molecular-weight phthalates exhibited lag associations with 25(OH)D with a 2-trimester lag period. In conclusion, the positive cross-sectional correlation between phthalate metabolites and 25(OH)D was partly affected by urine collection season. This study suggested that gestational phthalate exposure would have a lag association with maternal 25(OH)D levels.

[Association of neonatal blood calcium levels with perinatal factors and neonatal urinary calcium levels measured by an intelligent urine test system]

OBJECTIVE

To study the association of neonatal blood calcium levels with perinatal factors and neonatal urinary calcium levels measured by an intelligent urine test system.

METHODS

The medical data of 96 full-term singleton neonates with mild diseases were collected by a cross-sectional survey, who were hospitalized in the Department of Neonatology, The First Affiliated Hospital of Xi'an Jiaotong University, from June to August 2018. Urinary calcium levels measured by an intelligent urine test system, total blood calcium levels, ionized calcium levels, and the mother's calcium and vitamin D supplementation during pregnancy were recorded.

RESULTS

Compared with the group without vitamin D supplementation for the mother (17 neonates), the group with vitamin D supplementation for the mother (79 neonates) had significantly higher levels of total blood calcium and ionized calcium (P < 0.05).The group with both vitamin D and calcium supplementation for the mother (68 neonates) had significantly higher levels of ionized calcium than controls (28 neonate) (P=0.05). There was no significant difference in the levels of total blood calcium and ionized calcium between the group with calcium supplementation for the mother (74 neonates) and the group without calcium supplementation for the mother (22 neonates) (P > 0.05). The hypothermia group (5 neonates) had a significantly lower level of total blood calcium than the normal body temperature group (91 neonates) (P < 0.05). There was a significantly positive correlation between the maternal blood total calcium level and the neonatal blood total calcium and ionized calcium levels (r=0.881 and 0.703 respectively; P < 0.05). The neonatal urinary calcium level measured by the intelligent urine test system was significantly correlated with the blood ionized calcium level (r=0.526, P=0.025).

CONCLUSIONS

Vitamin D supplementation during pregnancy can increase the blood levels of total calcium and ionized calcium in neonates, and calcium supplementation alone cannot increase the blood levels of total calcium or ionized calcium in neonates. Hypothermia in neonates might cause the reduction in blood calcium levels. The urinary calcium level measured by the intelligent urine test system is positively correlated with the blood level of ionized calcium.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Vitamin D Supplementation during Pregnancy: An Evidence Analysis Center Systematic Review and Meta-Analysis

BACKGROUND

Given the high rates of vitamin D deficiency among pregnant women and possible effects on offspring health, a systematic review on this topic was conducted to help inform future practice guidelines.

OBJECTIVE

To evaluate associations between maternal vitamin D supplementation, maternal 25-hydroxyvitamin D (25(OH)D) concentrations, and health outcomes.

METHODS

A PubMed literature search was conducted to identify studies that examined the health effects of vitamin D supplementation during pregnancy on maternal and infant health outcomes published from 2000 to 2016. Among 976 identified publications, 20 randomized clinical trials met the inclusion criteria. The initial search was extended to include five studies published between July 2016 and September 2018.

MAIN OUTCOME MEASURES

Maternal and infant 25(OH)D concentrations, gestational diabetes, preeclampsia or gestational hypertension, cesarean section, maternal parathyroid hormone and calcium concentrations, and infant gestational age, birth weight, and birth length.

STATISTICAL ANALYSES

Mean differences, odds ratios, and 95% CIs were calculated, only for the initial search, using separate random-effects meta-analyses for each outcome.

RESULTS

Evidence was good or strong that maternal vitamin D supplementation significantly increased maternal (13 studies, n=18, mean difference, 14.1 ng/mL [35.2 nmol/L]; 95% CI=9.6-18.6 ng/mL [24.0-46.4 nmol/L]) and infant (nine studies, n=12; 9.7, 5.2, 14.2 ng/mL [24.2, 12.9, 35.5 nmol/L]) 25(OH)D concentrations, although heterogeneity was significant (I²=95.9% and I²=97.4, respectively, P<0.001). Evidence was fair that vitamin D supplementation significantly decreases maternal homeostatic model assessment-insulin resistance (five studies, n=7; -1.1, -1.5, -0.7) and increases infant birth weight (nine studies, n=11, 114.2, 63.4, 165.1 g), both had insignificant heterogeneity. A null effect of maternal supplementation on other maternal (preeclampsia, cesarean section) and infant (gestational age, birth length) outcomes was found.

CONCLUSIONS

Results show vitamin D supplementation during pregnancy improves maternal and infant 25(OH)D concentrations and may play a role in maternal insulin resistance and fetal growth. To further inform practice and policies on the amount of vitamin D, which supports a healthy pregnancy, high quality dose-response randomized clinical trials, which assess pregnancy-specific 25(OH)D thresholds, and appropriately powered clinical outcomes are needed.

Vitamin D Status and Associated Factors in Neonates in a Resource Constrained Setting

Vitamin D deficiency (VDD) is emerging as a serious public health problem globally; however due to lack of resources, vitamin D levels are not routinely measured among neonates. The study was conducted to determine vitamin D levels in neonates and factors associated with the same. A cross-sectional study was conducted among neonates admitted at neonatal ward of a tertiary care hospital. Means and proportions were calculated from summarized data in frequency tables. Chi square test was used to determine association between vitamin D and various associated factors such as sex, infant birth weight, gestation age, parity of the mother, maternal age, and HIV status of the mother. A total of 170 neonates were studied, out of which 80% had vitamin D deficiency. Neonates born to HIV-infected mothers were significantly less likely to have vitamin D deficiency (OR 0.21, 95% CI 0.06 - 0.77, p = 0.009). Subgroup analysis revealed the association to be stronger in terms neonates (p = 0.005). The association was not observed among preterm newborns. The prevalence of vitamin D deficiency in neonates was observed to be very high and needs more attention.

Association Between Vitamin D Supplementation During Pregnancy and Offspring Growth, Morbidity, and Mortality: A Systematic Review and Meta-analysis

IMPORTANCE

Whether vitamin D supplementation during pregnancy is beneficial and safe for offspring is unclear.

OBJECTIVE

To systematically review studies of the effects of vitamin D supplementation during pregnancy on offspring growth, morbidity, and mortality.

DATA SOURCES

Searches of Medline, Embase, and the Cochrane Database of Systematic Reviews were conducted up to October 31, 2017. Key search terms were vitamin D, pregnancy, randomized controlled trials, and offspring outcomes.

STUDY SELECTION

Randomized clinical trials of vitamin D supplementation during pregnancy and offspring outcomes.

DATA EXTRACTION AND SYNTHESIS

Two authors independently extracted data, and the quality of the studies was assessed. Summary risk ratio (RR), risk difference (RD) or mean difference (MD), and 95% CI were calculated using fixed-effects or random-effects meta-analysis.

MAIN OUTCOMES AND MEASURES

Main outcomes were fetal or neonatal mortality, small for gestational age (SGA), congenital malformation, admission to a neonatal intensive care unit, birth weight, Apgar scores, neonatal 25-hydroxyvitamin D (25[OH]D) and calcium concentrations, gestational age, preterm birth, infant anthropometry, and respiratory morbidity during childhood.

RESULTS

Twenty-four clinical trials involving 5405 participants met inclusion criteria. Vitamin D supplementation during pregnancy was associated with a lower risk of SGA (RR, 0.72; 95% CI, 0.52 to 0.99; RD, -5.60%; 95% CI, -0.86% to -10.34%) without risk of fetal or neonatal mortality (RR, 0.72; 95% CI, 0.47 to 1.11) or congenital abnormality (RR, 0.94; 95% CI, 0.61 to 1.43). Neonates with prenatal vitamin D supplementation had higher 25(OH)D levels (MD, 13.50 ng/mL; 95% CI, 10.12 to 16.87 ng/mL), calcium levels (MD, 0.19 mg/dL; 95% CI, 0.003 to 0.38 mg/dL), and weight at birth (MD, 75.38 g; 95% CI, 22.88 to 127.88 g), 3 months (MD, 0.21 kg; 95% CI, 0.13 to 0.28 kg), 6 months (MD, 0.46 kg; 95% CI, 0.33 to 0.58 kg), 9 months (MD, 0.50 kg; 95% CI, 0.01 to 0.99 kg), and 12 months (MD, 0.32 kg; 95% CI, 0.12 to 0.52 kg). Subgroup analysis by doses showed that low-dose vitamin D supplementation (≤2000 IU/d) was associated with a reduced risk of fetal or neonatal mortality (RR, 0.35; 95% CI, 0.15 to 0.80), but higher doses (>2000 IU/d) did not reduce this risk (RR, 0.95; 95% CI, 0.59 to 1.54).

CONCLUSIONS AND RELEVANCE

Vitamin D supplementation during pregnancy is associated with a reduced risk of SGA and improved infant growth without risk of fetal or neonatal mortality or congenital abnormality. Vitamin D supplementation with doses of 2000 IU/d or lower during pregnancy may reduce the risk of fetal or neonatal mortality.

Impact of vitamin D on pregnancy-related disorders and on offspring outcome

Observational studies from all over the world continue to find high prevalence rates of vitamin D insufficiency and deficiency in many populations, including pregnant women. Beyond its classical function as a regulator of calcium and phosphate metabolism, vitamin D elicits numerous effects in the human body. Current evidence highlights a vital role of vitamin D in mammalian gestation. During pregnancy, adaptations in maternal vitamin D metabolism lead to a physiologic increase of vitamin D levels, mainly because of an increased renal production, although other potential sources like the placenta are being discussed. A sufficient supply of mother and child with calcium and vitamin D during pregnancy ensures a healthy bone development of the fetus, whereas lack of either of these nutrients can lead to the development of rickets in the child. Moreover, vitamin D insufficiency during pregnancy has consistently been associated with adverse maternal and neonatal pregnancy outcomes. In multitudinous studies, low maternal vitamin D status was associated with a higher risk for preeclampsia, gestational diabetes mellitus and other gestational diseases. Likewise, several negative consequences for the fetus have been reported, including fetal growth restriction, increased risk of preterm birth and a changed susceptibility for later-life diseases. However, study results are diverging and causality has not been proven so far. Meta-analyses on the relationship between maternal vitamin D status and pregnancy outcomes revealed a wide heterogeneity of studied populations and the applied methodology in vitamin D assessment. Until today, clinical guidelines for supplementation cannot be based on high-quality evidence and it is not clear if the required intake for pregnant women differs from non-pregnant women. Long-term safety data of vitamin D supplementation in pregnant women has not been established and overdosing of vitamin D might have unfavorable effects, especially in mothers and newborns with mutations of genes involved in vitamin D metabolism. Reliable data from large observational and interventional randomized control trials are urgently needed as a basis for any detailed and safe recommendations for supplementation in the general population and, most importantly, in pregnant women. This is of utmost importance, as ensuring a sufficient vitamin D-supply of mother and child implies a great potential for the prevention of birth complications and development of diseases.

Vitamin D in pediatric age: consensus of the Italian Pediatric Society and the Italian Society of Preventive and Social Pediatrics, jointly with the Italian Federation of Pediatricians

Vitamin D plays a pivotal role in the regulation of calcium-phosphorus metabolism, particularly during pediatric age when nutritional rickets and impaired bone mass acquisition may occur.Besides its historical skeletal functions, in the last years it has been demonstrated that vitamin D directly or indirectly regulates up to 1250 genes, playing so-called extraskeletal actions. Indeed, recent data suggest a possible role of vitamin D in the pathogenesis of several pathological conditions, including infectious, allergic and autoimmune diseases. Thus, vitamin D deficiency may affect not only musculoskeletal health but also a potentially wide range of acute and chronic conditions. At present, the prevalence of vitamin D deficiency is high in Italian children and adolescents, and national recommendations on vitamin D supplementation during pediatric age are lacking. An expert panel of the Italian Society of Preventive and Social Pediatrics reviewed available literature focusing on randomized controlled trials of vitamin D supplementation to provide a practical approach to vitamin D supplementation for infants, children and adolescents.

They Are What You Eat: Can Nutritional Factors during Gestation and Early Infancy Modulate the Neonatal Immune Response?

The ontogeny of the human immune system is sensitive to nutrition even in the very early embryo, with both deficiency and excess of macro- and micronutrients being potentially detrimental. Neonates are particularly vulnerable to infectious disease due to the immaturity of the immune system and modulation of nutritional immunity may play a role in this sensitivity. This review examines whether nutrition around the time of conception, throughout pregnancy, and in early neonatal life may impact on the developing infant immune system.

Association between Vitamin Intake during Pregnancy and Risk of Small for Gestational Age

Pregnancy increases the requirements of certain nutrients, such as vitamins, to provide nutrition for the newborn. The aim was to analyze the association between dietary intake of vitamins during pregnancy and risk of having a small for gestational age (SGA) newborn. A matched case-control study was conducted (518 cases and 518 controls of pregnant women) in Spain. Dietary vitamin intake during pregnancy was assessed using a validated food frequency questionnaire, categorized into quintiles. Odds ratios (ORs) and their 95% confidence intervals (CI) were estimated with conditional regression logistic models. A protective association was observed between maternal dietary intake of vitamins A and D and SGA. For vitamin B3 and B6, the observed protective effect was maintained after adjusting for potential confounding factors. For vitamin B9, we found only an effect in quintiles 3 and 4 (OR = 0.64; 95% CI, 0.41-1.00; OR = 0.58; 95% CI, 0.37-0.91). Protective effect for vitamin B12 was observed in 4th and 5th quintiles (OR = 0.61; 95% CI, 0.39-0.95; OR = 0.68; 95% CI, 0.43-1.04). No associations were detected between dietary intake of vitamins B2, E and C intake and SGA. Our results suggest a positive association between dietary vitamin intake during pregnancy and the weight of the newborn, although more studies are necessary and there could be a ceiling effect for higher intakes of some vitamins cannot be discarded.

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.

Vitamin supplementation in pregnancy

Ensuring that a woman is well-nourished, both before and during pregnancy, is crucial for the health of the woman and that of the unborn child.(1) Maternal deficiency in key nutrients has been linked to pre-eclampsia, restricted fetal growth, neural tube defects, skeletal deformity and low birth weight.(1,2) Many nutritional supplements containing vitamins, minerals and other micronutrients are heavily marketed to women for all stages of pregnancy. However, much of the evidence for vitamin supplementation in pregnancy comes from studies carried out in low-income countries,(3) where women are more likely to be undernourished or malnourished than within the UK population. The challenges lie in knowing which supplements are beneficial and in improving uptake among those at most need. Here we summarise current UK guidance for vitamin supplementation in pregnancy and review the evidence behind it.