Maternal vitamin D status, its associated factors and the course of pregnancy in Thai women.
ABSTRACT CONTEXT: There are limited data on the prevalence of vitamin D inadequacy in pregnant women living in Southeast Asia, and changes in their vitamin D status during pregnancy. OBJECTIVES: To determine the prevalence of vitamin D inadequacy, its predictive factors and the changes in vitamin D status during the course of pregnancy. DESIGN AND PATIENTS: A prospective study of 120 pregnant Thai women with gestational age<14 weeks. MEASUREMENTS: Serum 25 hydroxyvitamin D (25OHD) and clinical data were obtained at the first visit, in the second and third trimesters of pregnancy. Vitamin D inadequacy was defined as 25OHD<75 nmol/L. RESULTS: The prevalences of vitamin D inadequacy were 83.3%, 30.9% and 27.4% for the first, second and third trimesters. The independent predictors of vitamin D inadequacy in the third trimester were not drinking vitamin fortified milk (OR 11.42; 95%CI:3.12-41.86), not taking prenatal vitamins (OR 9.70; 95%CI:2.28-41.19) and having vitamin D deficiency in the first trimester (OR 10.58; 95%CI:2.89-38.80). Vitamin D deficiency was not found in women taking prenatal vitamins. However, 20 women who took at least 400 IU/d of vitamin D from prenatal vitamins still had vitamin D insufficiency in the third trimester. CONCLUSIONS: Vitamin D inadequacy is common in pregnant Thai women, especially in the first trimester. Vitamin D supplementation may be needed prior to conception and during pregnancy. For areas with abundant sun exposure like Thailand, vitamin D supplementation at 400 IU/d is likely to prevent vitamin D deficiency, but is inadequate to prevent vitamin D insufficiency even at 800 IU/d. © 2012 Blackwell Publishing Ltd.
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ABSTRACT: Vitamin D has direct influence on molecular pathways proposed to be important in the pathogenesis of preeclampsia, yet the vitamin D-preeclampsia relation has not been studied. We aimed to assess the effect of maternal 25-hydroxyvitamin D [25(OH)D] concentration on the risk of preeclampsia and to assess the vitamin D status of newborns of preeclamptic mothers. We conducted a nested case-control study of pregnant women followed from less than 16 wk gestation to delivery (1997-2001) at prenatal clinics and private practices. Patients included nulliparous pregnant women with singleton pregnancies who developed preeclampsia (n = 55) or did not develop preeclampsia (n = 219). Women's banked sera were newly measured for 25(OH)D. The main outcome measure was preeclampsia (new-onset gestational hypertension and proteinuria for the first time after 20 wk gestation). Our hypotheses were formulated before data collection. Adjusted serum 25(OH)D concentrations in early pregnancy were lower in women who subsequently developed preeclampsia compared with controls [geometric mean, 45.4 nmol/liter, and 95% confidence interval (CI), 38.6-53.4 nmol/liter, vs. 53.1 and 47.1-59.9 nmol/liter; P < 0.01]. There was a monotonic dose-response relation between serum 25(OH)D concentrations at less than 22 wk and risk of preeclampsia. After confounder adjustment, a 50-nmol/liter decline in 25(OH)D concentration doubled the risk of preeclampsia (adjusted odds ratio, 2.4; 95% CI, 1.1-5.4). Newborns of preeclamptic mothers were twice as likely as control newborns to have 25(OH)D less than 37.5 nmol/liter (adjusted odds ratio, 2.2; 95% CI, 1.2-4.1). Maternal vitamin D deficiency may be an independent risk factor for preeclampsia. Vitamin D supplementation in early pregnancy should be explored for preventing preeclampsia and promoting neonatal well-being.Journal of Clinical Endocrinology & Metabolism 09/2007; 92(9):3517-22. · 6.43 Impact Factor
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ABSTRACT: To evaluate calcium-regulating hormones and parathyroid hormone-related peptide (PTHrP) in normal human pregnancy and postpartum in women not deficient in vitamin D. A prospective longitudinal study was conducted in pregnant Saudi women during the course of pregnancy (n = 40), at term and 6 weeks postpartum (n = 18). Maternal concentrations of serum calcidiol and calcitriol were determined, together with those of serum intact-parathyroid hormone (PTH), PTHrP, calcitonin, osteocalcin, human placental lactogen (hPL), prolactin, vitamin D binding protein, alkaline phosphatase, calcium, phosphate and magnesium. A group of non-pregnant women (n = 280) were included for comparative purposes. The calcidiol concentrations decreased (mean +/- S.D.) significantly from 54 +/- 10 nmol/l in the first trimester to 33 +/- 8 nmol/l in the third trimester (P < 0.001) and remained decreased at term and postpartum (both P < 0.001). The calcitriol concentration increased through pregnancy, from 69 +/- 17 pmol/l in the first trimester to 333 +/- 83 pmol/l at term (P < 0.001). Intact-PTH concentrations increased from 1.31 +/- 0.25 pmol/l in the first trimester to 2.26 +/- 0.39 pmol/l in the second trimester, but then declined to values of the first trimester and increased significantly postpartum (4.02 +/- 0.36 pmol/l) (P < 0.001). PTHrP concentration increased through pregnancy from 0.81 +/- 0.12 pmol/l in the first trimester to 2.01 +/- 0.22 pmol/l at term and continued its increase postpartum (2.63 +/- 0.15 pmol/l) (P < 0.001). Significant positive correlations were evident between PTHrP and alkaline phosphatase up to term (r = 0.051, P < 0.001) and between PTHrP and calcitriol (r = 0.46, P < 0.001), osteocalcin (r = 0.23, P < 0.05) and prolactin (r = 0.41, P < 0.05) during pregnancy. Osteocalcin started to increase from 0.13 +/- 0.01 nmol/l in the second trimester, through pregnancy and postpartum (P < 0.001). Calcitonin was increased more than twofold by the second trimester compared with the first trimester (P < 0.001) and subsequently decreased (P < 0.001). Prolactin concentrations were significantly greater in the second (6724 +/- 1459 pmol/l) and third (8394 +/- 2086 pmol/l) trimesters compared with values before pregnancy (P < 0.001). hPL, increased throughout the course of pregnancy, reaching a maximum at term (7.61 +/- 2.57 microIU/ml). There was no direct correlation between serum calcitriol concentrations during pregnancy and serum prolactin (r = -0.12, P < 0.19) or serum hPL (r = 0.17, P < 0.21). Significant changes were observed in the serum concentrations of calcium and phosphate, but not in that of magnesium, during the course of pregnancy; calcium concentrations showed a maximal decrease at term. Changes in serum PTHrP during the course of pregnancy, at term and postpartum have been demonstrated, suggesting that the placenta (during pregnancy) and mammary glands (postpartum) are the main sources of PTHrP. No support for the concept of 'physiological hyperparathyroidism' of pregnancy could be demonstrated in the present work. The pregnancy-induced increase in calcitriol concentration may thus be the primary mediator of the changes in maternal calcium metabolism, but the involvement of other factors cannot be excluded.European Journal of Endocrinology 10/1997; 137(4):402-9. · 3.14 Impact Factor
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ABSTRACT: To determine the pregnancy outcome as a function of the first-trimester serum 25-hydroxyvitamin D(3) [25(OH)D] status and to compare the 25(OH)D levels in the first and third trimesters. Pregnant women (n=466) tested for serum 25(OH)D levels during the first trimester were followed up until the end of pregnancy, and the obstetric and neonatal outcomes were compared in reference to the baseline 25(OH)D status. The third-trimester 25(OH)D levels were additionally measured in a subset of women (n=148). The obstetric and neonatal outcomes did not vary as a function of the first-trimester 25(OH)D status. Neither did the 25(OH)D levels vary as a function of pregnancy outcomes. Overall, the 25(OH)D levels significantly decreased from the first to the third trimester. The first- and third-trimester 25(OH)D levels of samples initially taken during autumn/winter were significantly lower than those that were initially taken during spring/summer. Interestingly, the decrease in 25(OH)D levels during the third trimester was independent of the season of sampling. The pregnancy outcome was independent of the first-trimester 25(OH)D status. Overall, the 25(OH)D levels significantly decreased in the third trimester. More research in this area is warranted.International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics 09/2011; 116(1):6-9. · 1.41 Impact Factor