Vitamin D plasma concentrations in pregnant women and their preterm newborns

Abstract

BackgroundVitamin D deficiency is a global public health issue. More than half of pregnant women are affected by vitamin D insufficiency/deficiency. Studies suggest an association between low vitamin D concentrations during pregnancy with intrauterine growth restriction and prematurity. This study aimed to describe the concentrations of 25(OH)D (25-hydroxyvitamin D) of mothers who delivered preterm newborns compared to women with full-term pregnancy deliveries, as well as to relate 25(OH)D blood concentrations of mothers with those of their newborns.MethodThis cross-sectional study was conducted with 66 mothers who had given birth to preterm babies and their preterm newborns (PTNB, < 32 weeks), and 92 women who had given birth at the full-term of their pregnancy and their newborns (FTNB). Data were collected on the characteristics of mothers (gestational age, diseases, and habits) and newborns (anthropometry and adequacy for gestational age). Ten milliliters of blood were drawn from the mothers and the umbilical cord of newborns at birth to identify the 25(OH)D, parathyroid hormone, calcium, phosphorus, and alkaline phosphatase concentrations.ResultsMothers in the PTNB group had significantly lower mean 25(OH)D blood levels (21.7 ± 10.8 ng/mL vs. 26.2 ± 9.8 ng/mL; p = 0.011) and were three times more likely to have insufficiency when compared to mothers in the FTNB group (OR = 2.993; 95%CI 1.02–8.74). Newborns in the PTNB group also had lower 25(OH)D concentrations compared to FTNB group (25.9 ± 13.9 ng/dL vs. 31.9 ± 12.3 ng/dL; p = 0.009). There was a directly proportional correlation between mother and newborn umbilical cord 25(OH)D concentrations in PTNB (r = 0.596; p < 0.001) and FTNB (r = 0.765; p < 0.001).ConclusionMothers who delivered preterm babies and their preterm newborns had lower 25(OH)D concentrations compared to women who had given birth at the full-term of their pregnancy. In both groups, 25(OH)D concentrations of the mothers correlated directly with those of the newborns, and this correlation was higher in the full-term birth group. Nevertheless, the recommended universal vitamin D supplementation in pregnant women to curb the risk of preterm birth is still incipient. More studies are required to clarify the particularities of vitamin D metabolism further and define the adequate 25(OH)D concentrations throughout pregnancy.

Does Vitamin D Deficiency in Different Periods of Gestation Have the Same Effect on Preterm Birth? A Systematic Review and Meta-Analysis

“…A total of 1639 were excluded after reading titles and/or abstracts, and 75 articles were subjected to a full-text review. After reading the full text, a total of 24 cohorts were invited to participate, which included 13 cohort studies [27][28][29][30][31][32][33][34][35][36][37][38][39], seven case-control studies [40][41][42][43][44][45][46] and four cross-sectional studies [47][48][49][50].…”

“…Because three studies [29][30][31] of 24 measured serum 25(OH)D concentrations at two or three periods of pregnancies, our meta-analysis included nine studies [28][29][30][31]36,39,41,44,46] in the first trimester, 11 studies [27,[30][31][32][33][34][35]37,38,40,43] in the second trimester, and nine studies [29][30][31]42,45,[47][48][49][50] in the third trimester.…”

“…The included studies from the United States, Canada, Australia, New Zealand, Spain, Netherlands, Swedish, Poland, Brazil, Kenya, China, Singapore and Thailand. A total of nine studies [28,30,31,33,37,40,[48][49][50] were from Asian countries, six [36,41,43,[45][46][47] from American countries, five [29,34,38,39,42] from European countries, three [27,35,44] from Oceanian countries, and one [32] was from African countries. Among 24 studies, 21 [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] cohort studies or case-control studies were appraised by NOS, resulting with scores above 6, while four [47][48][49][50] cross-sectional studies were appr...…”

Vitamin D Levels in Pregnant Congolese Women and Their New-Borns, and the Association with Neonatal Outcomes – A Pilot Study

“…The primary objective of this project was to assess the vitamin D status in maternal serum, cord blood and to study its association with various neonatal outcomes(birth weight,mode of delivery, preterm births and small for gestational age). Vitamin D de ciency was de ned as serum levels of 25(OH)D less than 30 ng/dL [20] .…”

“…Although, there is ambiguity in the optimal serum concentration of vitamin D, levels above 30 ng/mL (75 nmol/L) is considered su cient; 21-29 ng/mL (51-74 nmol/L) insu cient and below 20 ng/mL (50 nmol/L) is considered de cient [12,19] . The recommended levels for special groups such as pregnancy are higher than 30 ng/mL [20] . Recent studies also suggest association of vitamin D with cancer, cardiovascular disease, diabetes and immunity, however enough high quality evidence is still lacking to support a cause-and-effect relationship [21] .…”