A comparative analysis of maternal and fetal 25-hydroxyvitamin D in pregnant women with and without gestational diabetes mellitus

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.

Maternal and Neonatal 3-epi-25-hydroxyvitamin D Concentration and Factors Influencing Their Concentrations

BACKGROUND

Little is known about the presence of 3-epi-25 hydroxyvitamin D in maternal and neonatal circulation, the extent of its contribution to total 25 hydroxyvitamin D, or factors influencing its levels.

METHODS

A total of 1502 and 1321 archived maternal and umbilical cord serum samples from the Hyperglycemia and Adverse Pregnancy Outcome Study cohort from Hong Kong were assayed for 25(OH)D2, 25(OH)D3, and isomeric form of 25(OH)D3 (3-epi-25(OH)D3) by a liquid chromatography-tandem mass spectrometry method.

RESULTS

Vitamin D deficiency (total serum 25(OH)D level < 50 nmol/L) and severe vitamin D deficiency (total serum 25(OH)D level < 25 nmol/L) occurred in 590 (39.3%) and 25 (1.7%) mothers, respectively. 3-epi-25(OH)D3 could be detected in 94.5% of maternal and 92.1% of neonatal umbilical sera, with the highest 3-epi-25(OH)D3 levels contributing to 19.9% and 15.3% of the maternal and umbilical cord sera 25(OH)D3 levels, respectively. Pregnancy with a male fetus, ambient solar radiation, and maternal glycemia and 25(OH)D3 levels were independent factors associated with maternal 3-epi-25(OH)D3 level. Advanced maternal age, multiparity, maternal gestational weight gain below the Institute of Medicine recommendation, maternal glycemic status, and earlier gestational age at delivery were significantly associated with higher umbilical cord serum 3-epi-25(OH)D3.

CONCLUSIONS

3-epi-25(OH)D3 accounted for a significant portion of total 25(OH)D in maternal and neonatal circulations. Further study is needed to determine the possible mechanism underlying this observation.

An investigation of vitamin D deficiency in pregnant women and their infants in Giresun province located in the Black Sea region of Turkey

The aim of this study is to investigate vitamin D deficiency and the associated risk factors in pregnant women and their infants in the Black Sea region of Turkey. One hundred and twenty healthy pregnant women in the last trimester and their healthy newborn pairs were observed between June and August 2017 in Giresun province. The serum 25(OH)D3 and calcium levels were measured through the samples collected from maternal and neonatal cord blood. The effects of maternal lifestyle on the maternal vitamin D levels were assessed by multiple regression analysis. The mean concentrations of 25(OH)D3 were found to be 9.54 ± 6.35 ng/mL and 11.16 ± 6.52 ng/mL in the maternal and neonatal cord blood sera, respectively. Vitamin D deficiency (≤20 ng/mL) and severe vitamin D deficiency (≤5 ng/mL) were observed in between 94.2% and 24.2% of mothers and 90% and 10% of infants, respectively. The clothing style, the consumption of milk/dairy products and antenatal multivitamin supplement usage were found as significant factors on the serum vitamin D levels. Even during the Summer months, the vitamin D deficiency in mothers and infants was observed at high rates in the Eastern Black Sea region of Turkey. As a result, it has been concluded that routine maternal serum 25(OH)D3 measurements for clinical follow-up, vitamin D supplementation and regular consumption of dairy products should be recommended. Impact Statement What is already known on this subject? Vitamin D deficiency is a very important risk factor to be considered for maternal and infant health. In a large number of studies, it has been observed that the risk of a vitamin D deficiency in women during their pregnancy was found to be higher, depending on the various strong influences such as the demographic and maternal lifestyles. What the results of this study add? A vitamin D deficiency associated with the demographic and lifestyle factors of pregnant women and their infants was investigated in Giresun province, located in the Eastern Black Sea region of Turkey. The results of this study add that a vitamin D deficiency in the maternal and in the infants may be observed at high rates in regions with mostly rainy weather, even during the Summer months. What the implications are of these findings for clinical practice and/or further research? The vitamin D levels in infants can be determined indirectly by looking at the vitamin D levels in third trimester pregnancies. Furthermore, it is suggested as a non-invasive method to determine vitamin D levels by taking advantage of the maternal level, without measuring the vitamin D levels of infants. Thus, this will be effective to reduce health costs and to prevent the possible diseases affecting the future life of infants. Routine maternal serum 25(OH)D3 measurements for clinical follow-up, vitamin D supplementation and the regular consumption of dairy products should be recommended to pregnant women with risk factors, even in the Summer in the Black Sea Region of Turkey. In addition, further studies are needed to investigate the vitamin D deficiency associated with the demographic and lifestyle factors of pregnant women and their infants, especially for the different locations of Turkey.