Association of maternal serum 25-hydroxyvitamin D concentrations in second and third trimester with risk of macrosomia

Association between maternal lipid profiles and vitamin D status in second trimester and risk of LGA or SGA: a retrospective study

Background

Accumulating evidence has linked dyslipidemia during pregnancy to the risk of delivering infants born either large for gestational age (LGA) or small for gestational age (SGA). However, the effects of the vitamin D status on these relationships require further investigation. This study investigated whether the relationship between lipid profiles and the risk of LGA or SGA was influenced by vitamin D levels during the second trimester.

Methods

Maternal lipid profile levels, including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and vitamin D levels, were measured in a cohort of 6,499 pregnant women during the second trimester. Multivariate regression models and subgroup analyses were employed to evaluate the potential associations between maternal lipid profiles, vitamin D levels, and the risk of LGA or SGA.

Results

The prevalence of SGA infants was 9.8% (n=635), whereas that of LGA infants was 6.9% (n=447). Maternal TG levels were found to be positively associated with the risk of LGA (odds ratio [OR] = 1.41, 95% confidence interval [CI]:1.17-1.70), whereas a negative association was observed between maternal TG, TC, LDL-C levels, and risk of SGA. Additionally, mothers with higher HDL-C levels were less likely to give birth to an LGA infant (OR=0.58, 95% CI:0.39-0.85). Importantly, associations between TG, TC, LDL-c, and SGA as well as between TG and LGA were primarily observed among pregnant women with insufficient vitamin D levels. As for HDL-C, the risk of LGA was lower in mothers with sufficient vitamin D (OR = 0.42, 95% CI:0.18-0.98) compared to those with insufficient vitamin D (OR = 0.65, 95% CI:0.42-0.99).

Conclusion

Vitamin D status during the second trimester exerts a modifying effect on the association between lipid profiles and the risk of LGA and SGA infants.

Association of Parity with the Risks of Gestational Diabetes and Macrosomia: A Retrospective Cohort Study in Nanjing, China

BACKGROUND

After implementing the two-child policy, more Chinese women who had a previous delivery had their second child. Nevertheless, the impacts of parity on Gestational Diabetes (GDM) and macrosomia have not been fully confirmed. Therefore, we aimed to analyse the characteristics of pregnancy by parity and evaluate the association of parity with risks of GDM/macrosomia in a Chinese population.

METHODS

A total of 193,410 pregnant women (including 148,293 primiparae and 45,117 multiparae) with complete information were included. Univariate and multivariate logistic regression analyses were used to examine the association between parity and risks of GDM/macrosomia.

RESULTS

With the gradual implementation of the two-child policy, the proportion of multiparae increased rapidly and then decreased slightly. Multiparae were more likely to be older and have higher intrapartum BMI, as compared to primiparae (P < 0.001). Univariate regression analyses suggested that parity could increase the risks of GDM and macrosomia; while after adjustment, the association between parity and GDM risk disappeared, and the effects of parity on macrosomia risk and birth weight of babies were also weakened. Further, stratified analysis showed that parity only increased the risk of GDM in women over 30 years, and the effects of parity on macrosomia risk and birth weight were more pronounced among women over 30 years compared to women under 30 years.

CONCLUSION

Parity was not associated with GDM risk, but mildly associated with macrosomia risk. Particular attention should be paid to multiparae with advanced age to reduce the risks of GDM and macrosomia.

Maternal plasma vitamin D levels across pregnancy are not associated with neonatal birthweight: findings from an Australian cohort study of low-risk pregnant women

BACKGROUND

In utero environments can be highly influential in contributing to the development of offspring obesity. Specifically, vitamin D deficiency during pregnancy is associated with adverse maternal and child health outcomes, however its relationship with offspring obesity remains unclear. We assessed maternal vitamin D status across pregnancy, change in plasma vitamin D concentrations and associations with neonatal birthweight, macrosomia and large for gestational age.

METHODS

Women (n = 221) aged 18-40 years with singleton (low-risk) pregnancies, attending antenatal clinics at a tertiary-level maternity hospital were recruited at 10-20 weeks gestation. Medical history, maternal weight and blood samples at three antenatal clinic visits were assessed; early (15 ± 3 weeks), mid (27 ± 2 weeks) and late (36 ± 1 weeks) gestation. Maternal 25(OH)D was analysed from stored plasma samples via liquid chromatography-tandem mass spectrometry (LC/MS/MS). Neonatal growth parameters were collected at birth. Unadjusted and adjusted linear and logistic regression assessed associations of maternal vitamin D with birthweight, macrosomia and large for gestational age.

RESULTS

Mean plasma 25(OH)D increased from early (83.8 ± 22.6 nmol/L) to mid (96.5 ± 28.9 nmol/L) and late (100.8 ± 30.8 nmol/L) gestation. Overall 98% of women were taking vitamin D-containing supplements throughout their pregnancy. Prevalence of vitamin D deficiency (25(OH)D < 50 nmol/L) was 6.5%, 6.3% and 6.8% at early, mid and late pregnancy respectively. No statistically significant association was found between 25(OH)D or vitamin D deficiency at any timepoint with neonatal birthweight, macrosomia or large for gestational age.

CONCLUSIONS

Prevalence of vitamin D deficiency was low in this cohort of pregnant women and likely related to the high proportion of women taking vitamin D supplements during pregnancy. Maternal 25(OH)D did not impact offspring birth weight or birth size. Future studies in high-risk pregnant populations are needed to further assess maternal vitamin D status and factors in utero which promote early life obesity.

Vitamin D Status of Infants of Mothers with Gestational Diabetes: Status at Birth and a Randomized Controlled Trial of Vitamin D Supplementation across Infancy

BACKGROUND

Vitamin D status and requirements of infants of women with gestational diabetes mellitus (GDM) are unclear.

OBJECTIVES

The objectives were to assess vitamin D status in infants of mothers with GDM and compare vitamin D status in response to 400 vs. 1000 IU/d vitamin D supplementation in infants born with serum 25-hydroxyvitamin D [25(OH)D] <50 nmol/L.

METHODS

Women with GDM delivering full-term infants (n = 98; March 2017-2019, Montreal, Canada) were surveyed for demographic and lifestyle factors. Pregnancy history was obtained from medical records. Newborn serum 25(OH)D was measured (immunoassay) and categorized as <30 (deficient) or ≥40 nmol/L (adequate). Breastfed neonates (n = 16) with serum 25(OH)D <50 nmol/L at birth were randomly assigned to 400 or 1000 IU/d of supplemental cholecalciferol (vitamin D3), and serum 25(OH)D was measured at baseline (≤1 mo) and 3, 6, and 12 mo of age. Groups were compared using a linear mixed-effects model and Tukey-Kramer post hoc tests.

RESULTS

Mean newborn serum 25(OH)D was 46.4 (95% CI: 43.9, 49.9) nmol/L, with 15.3% (95% CI: 8.2%, 22.4%) <30 nmol/L and 61.2% (95% CI: 51.6%, 70.9%) ≥40 nmol/L. During the trial, most infants were breastfed to 3 mo (400 IU/d: 87.5%; 1000 IU/d: 75.0%). Mean (± SEM) infant serum 25(OH)D was higher in the 1000-IU/d group at 3 mo (79.9 ± 5.9 vs. 111.5 ± 15.2 nmol/L; P = 0.0263), and although not different at 6-12 mo, was maintained at >50 nmol/L.

CONCLUSIONS

Most infants of women with GDM had adequate vitamin D status in this study. In those born with serum 25(OH)D <50 nmol/L, vitamin D status was corrected by 3 mo of age in response to 400 or 1000 IU/d of supplemental vitamin D. Dietary guidance should continue to recommend that all women who could become pregnant take a multivitamin supplement and that breastfed infants receive 400 IU/d of supplemental vitamin D. This study and ancillary trial were registered at clinicaltrials.gov (https://www.

CLINICALTRIALS

gov/ct2/show/NCT02563015) as NCT02563015.

The Gestational Effects of Maternal Bone Marker Molecules on Fetal Growth, Metabolism and Long-Term Metabolic Health: A Systematic Review

Fetal exposure in adverse environmental factors during intrauterine life can lead to various biological adjustments, affecting not only in utero development of the conceptus, but also its later metabolic and endocrine wellbeing. During human gestation, maternal bone turnover increases, as reflected by molecules involved in bone metabolism, such as vitamin D, osteocalcin, sclerostin, sRANKL, and osteoprotegerin; however, recent studies support their emerging role in endocrine functions and glucose homeostasis regulation. Herein, we sought to systematically review current knowledge on the effects of aforementioned maternal bone biomarkers during pregnancy on fetal intrauterine growth and metabolism, neonatal anthropometric measures at birth, as well as on future endocrine and metabolic wellbeing of the offspring. A growing body of literature converges on the view that maternal bone turnover is likely implicated in fetal growth, and at least to some extent, in neonatal and childhood body composition and metabolic wellbeing. Maternal sclerostin and sRANKL are positively linked with fetal abdominal circumference and subcutaneous fat deposition, contributing to greater birthweights. Vitamin D deficiency correlates with lower birthweights, while research is still needed on intrauterine fetal metabolism, as well as on vitamin D dosing supplementation during pregnancy, to diminish the risks of low birthweight or SGA neonates in high-risk populations.

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.

Effect of maternal vitamin D status on risk of adverse birth outcomes: a systematic review and dose-response meta-analysis of observational studies

PURPOSE

Accumulating evidence suggests that vitamin D deficiency increases the risk of adverse perinatal outcomes. However, the dose-response relationship between maternal vitamin D status and adverse birth outcomes remains unclear. Focusing on prospective observational studies, we aimed to explore the dose-response relationship of vitamin D status with the risk of low birth weight (LBW), macrosomia (MA), preterm birth (PTB), small for gestational age (SGA), and intrauterine growth restriction (IUGR).

METHODS

Databases including PubMed, Embase, Scopus, and Web of Science were used up to 19 January 2021 to search for observational studies that fulfilled criteria as follows: cohort studies, case-cohort studies, or nested case-control studies. Random-effects models were used to pool relative risks (RRs) and 95% confidence intervals (CIs) in the observational studies.

RESULTS

A total of 72 publications were included in this systematic review and 71 in the meta-analysis. Maternal 25-hydroxyvitamin D (25(OH)D) concentrations were inversely associated with the risk of LBW (RR: 0.65; 95% CI 0.48-0.86), PTB (RR: 0.67; 95% CI 0.57-0.79), and SGA (RR: 0.61; 95% CI 0.49-0.76) in the highest versus lowest meta-analysis, but not associated with MA and IUGR. Linear dose-response analysis showed that each 25 nmol/L increase in 25(OH)D was associated with a 6% and 10% reduction in the risk of PTB (RR: 0.94; 95% CI 0.90-0.98) and SGA (RR: 0.90; 95% CI 0.84-0.97), respectively.

CONCLUSION

Our study suggests that a sufficient vitamin D status during pregnancy is protective against the risk of LBW, PTB, and SGA.

Maternal excess adiposity and serum 25-hydroxyvitamin D < 50 nmol/L are associated with elevated whole body fat mass in healthy breastfed neonates

BACKGROUND

Vitamin D status of pregnant women is associated with body composition of the offspring. The objective of this study was to assess whether the association between maternal vitamin D status and neonatal adiposity is modified by maternal adiposity preconception.

METHODS

Healthy mothers and their term appropriate weight for gestational age (AGA) infants (n = 142; 59% male, Greater Montreal, March 2016-2019) were studied at birth and 1 month postpartum (2-6 weeks). Newborn (24-36 h) serum was collected to measure total 25-hydroxyvitamin D [25(OH)D] (immunoassay); maternal pre-pregnancy BMI was obtained from the medical record. Anthropometry, body composition (dual-energy X-ray absorptiometry) and serum 25(OH)D were measured at 2-6 weeks postpartum in mothers and infants. Mothers were grouped into 4 categories based on their vitamin D status (sufficient 25(OH)D ≥ 50 nmol/L vs. at risk of being insufficient < 50 nmol/L) and pre-pregnancy BMI (< 25 vs. ≥25 kg/m2): insufficient-recommended weight (I-RW, n = 24); insufficient-overweight/obese (I-OW/O, n = 21); sufficient-recommended weight (S-RW, n = 69); and sufficient-overweight/obese (S-OW/O, n = 28). Partial correlation and linear fixed effects model were used while adjusting for covariates.

RESULTS

At birth, infant serum 25(OH)D mean concentrations were below 50 nmol/L, the cut-point for sufficiency, for both maternal pre-pregnancy BMI categories; 47.8 [95%CI: 43.8, 51.9] nmol/L if BMI < 25 kg/m2 and 38.1 [95%CI: 33.5, 42.7] nmol/L if BMI ≥25 kg/m2. Infant serum 25(OH)D concentrations at birth (r = 0.77; P < 0.0001) and 1 month (r = 0.59, P < 0.0001) were positively correlated with maternal postpartum serum 25(OH)D concentrations. Maternal serum 25(OH)D concentration was weakly correlated with maternal percent whole body fat mass (r = - 0.26, P = 0.002). Infants of mothers in I-OW/O had higher fat mass versus those of mothers in S-OW/O (914.0 [95%CI: 766.4, 1061.6] vs. 780.7 [95%CI: 659.3, 902.0] g; effect size [Hedges' g: 0.42]; P = 0.04 adjusting for covariates) with magnitude of difference of 220.4 g or ~ 28% difference.

CONCLUSIONS

Maternal and neonatal vitamin D status are positively correlated. In this study, maternal adiposity and serum 25(OH)D < 50 nmol/L are dual exposures for neonatal adiposity. These findings reinforce the importance of vitamin D supplementation early in infancy irrespective of vitamin D stores acquired in utero and maternal weight status.

Interplay between Maternal and Neonatal Vitamin D Deficiency and Vitamin-D-Related Gene Polymorphism with Neonatal Birth Anthropometry

Vitamin D deficiency during pregnancy has been associated with poor foetal growth and neonatal birth anthropometry. However, the associations were inconsistent and could be confounded by neonatal vitamin D status and genetic factors. Until recently, limited studies have concomitantly examined the effect of maternal and neonatal vitamin D deficiency and vitamin D-related single nucleotide polymorphisms (SNPs) on neonatal birth anthropometry. This study aims to examine the independent and combined effects of maternal and neonatal vitamin D deficiency and vitamin-D-related SNPs on neonatal birth anthropometry. This cross-sectional study included 217 mother−neonate dyads recruited from Hospital Serdang, Selangor, Malaysia, between 2015 and 2017. Plasma 25-hydroxyvitamin D (25OHD) concentration was measured in maternal and umbilical cord blood using ultra-high-performance liquid chromatography (UHPLC). Maternal and neonatal vitamin D Receptor (VDR) SNP (rs2228570) genotypes were determined using high-resolution melting (HRM). Group-specific component (GC) SNPs (rs4588 and rs7041) genotypes were determined using restriction fragment length polymorphism. Our results showed that: (1) maternal vitamin D deficiency (25OHD < 30 nmol/L) was inversely associated with birth weight, head circumference and crown−heel length; (2) neonatal SNPs, VDR rs2228570 and GC rs4588, were significantly associated with birth weight and head circumference, respectively; and (3) a potential interaction was observed between maternal VDR rs2228570 with maternal vitamin D deficiency on head circumference. These findings suggest that the underlying mechanisms of vitamin D on foetal growth are likely to be localised in the maternal compartment, mediated through the placenta, rather than through cellular mechanisms within the foetus. Further large-scale studies are warranted to validate and extend these findings.

Protective Effect of Maternal First-Trimester Low Body Mass Index Against Macrosomia: A 10-Year Cross-Sectional Study

OBJECTIVE

We aimed to assess whether maternal first-trimester low body mass index (BMI) has a protective effect against macrosomia.

METHODS

This was a cross-sectional study from January 1, 2011, to June 30, 2021, and 84,900 participants were included. The predictive performance of maternal first-trimester and parental pre-pregnancy BMI for macrosomia was assessed using the area under the receiver-operating characteristics curve (AUC). Multivariate logistic regression analyses were performed to evaluate the independent effect of maternal first-trimester low BMI on macrosomia. Interactions were investigated to evaluate the potential variation of the effect of first-trimester low BMI across different groups. Furthermore, interactions were also examined across groups determined by multiple factors jointly: a) gestational diabetes mellitus (GDM)/GDM history status, parity, and maternal age; and b) GDM/GDM history status, fetal sex, and season of delivery.

RESULTS

The proportion of macrosomia was 6.14% (5,215 of 84,900). Maternal first-trimester BMI showed the best discrimination of macrosomia (all Delong tests: P < 0.001). The protective effect of maternal first-trimester low BMI against macrosomia remained significant after adjusting for all confounders of this study [adjusted odds ratios (aOR) = 0.37, 95% CI: 0.32-0.43]. Maternal first-trimester low BMI was inversely associated with macrosomia, irrespective of parity, fetal sex, season of delivery, maternal age, and GDM/GDM history status. The protective effect was most pronounced among pregnant women without GDM/GDM history aged 25 to 29 years old, irrespective of parity (multipara: aOR = 0.32, 95% CI: 0.22-0.47; nullipara: aOR = 0.32, 95% CI: 0.24-0.43). In multipara with GDM/GDM history, the protective effect of low BMI was only observed in the 30- to 34-year-old group (aOR = 0.12, 95% CI: 0.02-0.86). For pregnant women without GDM/GDM history, the protective effect of maternal first-trimester low BMI against macrosomia was the weakest in infants born in winter, irrespective of fetal sex (female: aOR = 0.45, 95% CI: 0.29-0.69; male: aOR = 0.39, 95% CI: 0.28-0.55).

CONCLUSION

Maternal first-trimester low BMI was inversely associated with macrosomia, and the protective effect was most pronounced among 25- to 29-year-old pregnant women without GDM/GDM history and was only found among 30- to 34-year-old multipara with GDM/GDM history. The protective effect of maternal first-trimester low BMI against macrosomia was the weakest in winter among mothers without GDM/GDM history.

Second-trimester 25-hydroxyvitamin D status in pregnant women from southern China and risk of macrosomia: a large-scale retrospective cohort study

PURPOSE

The association between maternal vitamin D concentrations and birth weight is controversial. We conducted a large-scale retrospective cohort study in southern China to explore this relationship.

METHODS

From July 2017 to April 2019, we enrolled 10,586 pregnant women and measured serum vitamin D [via 25-hydroxyvitamin D, 25(OH)D] in the second trimester using electrochemiluminescence immunoassays. The association between macrosomia and 25(OH)D was analyzed using logistic regression and ROC curve.

RESULTS

Average vitamin D concentration was 61.1 ± 20.2 nmol/L. Additionally, 31.1% participants had 25(OH)D concentrations <50.0 nmol/L, while 68.9% exhibited concentrations ≥50.0 nmol/L. Of the subjects, 3.2% of women delivered macrosomic infants (neonatal birth weight ≥4000 g) and 96.8% did not. The macrosomia group had lower vitamin D concentrations than the non-macrosomia group (59.5 ± 22.3 vs. 61.2 ± 20.1, p < .05). Approximately a third of each group had vitamin D < 50.0 nmol/L (non-macrosomia, 31.3%; macrosomia, 35.9%; p = .055). After adjusting for confounding variables, women with 25(OH)D ≥ 50.0 nmol/L had 24.3% lower macrosomia risk than women with 25(OH)D < 50.0 nmol/L (adjusted OR = 0.757, 95% CI = 0.599-0.956, p = .0193). The predictive accuracy of vitamin D concentrations for evaluating macrosomia risk was 0.667 area under the ROC curve.

CONCLUSION

Maternal vitamin D levels are negatively correlated with macrosomia. Elevating vitamin D above 50.0 nmol/L may reduce macrosomia incidence.

The individual and joint effects of maternal 25(OH)D deficiency and gestational diabetes on infant birth size

BACKGROUND AND AIMS

To examine the independent effect of maternal serum 25-hydroxyvitamin D [25(OH)D] deficiency and its joint effect with gestational diabetes mellitus (GDM) on infant birth size.

METHODS AND RESULTS

This retrospective cohort study was conducted in 15,724 mother-offspring dyads in Beijing, China between 2016 and 2017. Outcomes included infant birth weight Z-score (adjusted for gestational age and sex) and large for gestational age (LGA). Exposures were maternal 25(OH)D concentrations. Linear and logistic regression models were used to assess the associations of exposures with continuous and binary outcomes, respectively. Exposure-outcome associations were not observed when analyzing 25(OH)D concentrations continuously or in quartiles (P > 0.05); however, mothers with severely deficient 25(OH)D concentrations (n = 307) had a decreased risk of LGA compared with those with sufficient 25(OH)D concentrations (≥30.0 ng/mL; n = 5400) (adjusted odds ratio (OR): 0.63; 95% confidence interval (CI): 0.42, 0.93). Compared to mothers with no 25(OH)D deficiency (≥20.0 ng/mL) and no GDM (n = 7975), those with both 25(OH)D deficiency and GDM (n = 1090) had 0.15 (95% CI: 0.09, 0.21) higher infant birth weight Z-score and a higher risk of LGA (OR: 1.29; 95% CI: 1.09, 1.52). Maternal 25(OH)D deficiency and GDM had additive interaction on the risk of LGA (relative risk due to interaction: 0.18).

CONCLUSION

Mothers with severely deficient 25(OH)D might have a decreased risk of LGA. However, the joint effect of maternal 25(OH)D deficiency and GDM might increase the risk of LGA. Our findings have clinical and public health implications and provide potential directions for future studies.

Association between variants in vitamin D-binding protein gene and vitamin D deficiency among pregnant women in china

BACKGROUND

The prevalence of vitamin D deficiency and insufficiency is extremely high in pregnant women worldwide. However, the association between single nucleotide polymorphisms (SNPs) in vitamin D metabolic pathway genes and 25-hydroxyvitamin D (25(OH)D) concentration among Chinese pregnant women is seldom reported. The risk of adverse neonatal outcomes due to maternal vitamin D deficiency has not been well investigated.

METHODS

A total of 815 pregnant women and 407 infants were enrolled in this study. Serum 25(OH)D concentration was detected. DNA was extracted from the maternal blood for genotyping genetic SNPs in vitamin D pathway. An XGBoost model was established based on SNPs combined with external variables.

RESULTS

Mean serum 25(OH)D level was 15.67 ± 7.98 ng/mL among the pregnant women. Seventy-five percent of pregnant women had 25(OH)D deficiency in China. SNPs of GC (rs17467825, rs4588, rs2282679, rs2298850, and rs1155563) were significantly associated with maternal 25(OH)D concentration. The influence of variants of rs17467825, rs4588, rs2282679, and rs2298850 on maternal 25(OH)D might be modified by vitamin D supplementation and sunshine exposure. An XGBoost model was established for monitoring 25(OH)D status in pregnant women and provided clinical advice to reduce the risk of 25(OH)D deficiency. Mothers with 25(OH)D deficiency hinted a risk for macrosomia.

CONCLUSION

A high prevalence of vitamin D deficiency in China has been confirmed. A clinical model was established to guide pregnant women to supplement vitamin D according to genotype. Furthermore, we suggest the effect of maternal vitamin D status on the risk of macrosomia.

Sunlight exposed body surface area is associated with serum 25-hydroxyvitamin D (25(OH)D) level in pregnant Minangkabau women, Indonesia

BACKGROUND

Vitamin D deficiency is highly prevalent in women, and living in a tropical country with a year-round abundance of sunlight as the primary source of vitamin D does not seem to guarantee adequate serum 25(OH)D. While living in the tropics, Minangkabau women are known to dress specifically according to their culture. This study was aimed to elucidate the association of sunlight exposed body surface area with serum 25(OH)D in pregnant Minangkabau women of Indonesia.

METHODS

We performed a cross-sectional study on 88 Minangkabau women in late pregnancy. Lifestyle data were collected using a questionnaire, and dietary intake of vitamin D was calculated from 24-h food recall. The skin pigmentation type was determined by the Fitzpatrick scale, and the body surface area exposed to sunlight was estimated. Serum 25(OH)D was quantified by ELISA method. Serum 25(OH)D differences according to the duration of sunlight exposure, skin pigmentation type, and sunscreen use were statistically analyzed by ANOVA. The correlation of sunlight exposed body surface area and serum 25(OH)D was analyzed by Spearman's correlation.

RESULTS

Nearly half of the subjects (n = 40; 45.5%) were deficient in vitamin D (< 20 ng/ml) with serum 25(OH)D level 23.0 ± 10.0 ng/ml (mean ± SD) and the estimated daily intake of vitamin D was 5.6 ± 3.9 μg/1000 kcal/day (mean ± SD). The median percentage of body area exposed to sunlight was 15.8%. There were no differences in serum 25(OH)D levels according to sunlight exposure time, skin pigmentation type, and sunscreen use. The percentage of body area exposed to sunlight was positively correlated with serum 25(OH)D level (Spearman's ρ = 0.403; p < 0.001).

CONCLUSIONS

Vitamin D deficiency is prevalent in pregnant Minangkabau women. Since increasing body surface area exposed to sunlight may not be culturally acceptable, vitamin D supplementation needs to be considered in this population.

Combined Effect of Maternal Vitamin D Deficiency and Gestational Diabetes Mellitus on Trajectories of Ultrasound-Measured Fetal Growth: A Birth Cohort Study in Beijing, China

OBJECTIVE

Few studies have examined whether maternal 25(OH)D deficiency and gestational diabetes mellitus (GDM) jointly affect fetal growth. We aimed to examine the separate and combined effects of maternal 25(OH)D deficiency and GDM on trajectories of fetal growth.

METHODS

We established a birth cohort (2016-2017) with 10,913 singleton pregnancies in Tongzhou Maternal and Child Health Hospital of Beijing, China. Maternal 25(OH)D deficiency (serum 25(OH)D concentration < 20.0 ng/mL) was detected, and GDM was diagnosed at 24~28 gestational weeks. Fetal growth was assessed by longitudinal ultrasound measurements of estimated fetal weight (EFW) and abdominal circumference (AC) from 28 gestational weeks to delivery, both of which were standardized as gestational-age-adjusted Z-score. A k-means algorithm was used to cluster the longitudinal measurements (trajectories) of fetal growth. Logistic regression models were used for estimating exposure-outcome associations and additive interactions.

RESULTS

We identified two distinct trajectories of fetal growth, and the faster one resembling the 90^th centile curve in the reference population was classified as excessive fetal growth. Maternal 25(OH)D deficiency and GDM were independently associated with an increased risk of excessive fetal growth. The combination of maternal 25(OH)D deficiency and GDM was associated with an increased risk of excessive fetal growth assessed by EFW Z-score (odds ratio (OR): 1.36; 95% confidence interval (CI): 1.15~1.62) and AC Z-score (OR (95% CI): 1.32 (1.11~1.56)), but the relative excess risks attributable to interaction were nonsignificant (P > 0.05).

CONCLUSION

Maternal 25(OH)D deficiency and GDM may jointly increase the risk of excessive fetal growth. Interventions for pregnancies with GDM may be more beneficial for those with 25(OH)D deficiency than those without regarding risk of excessive fetal growth, if confirmed in a large sample.