Dynamic Changes in Serum 25-Hydroxyvitamin D during Pregnancy and Lack of Effect on Thyroid Parameters

Abstract

Background & AimsTo explore vitamin D status and its dynamic changes during pregnancy in women living in Northeast China. The association between 25-hydroxyvitamin D and serum calcium, phosphate and parathyroid hormone was studied. Because vitamin D deficiency or thyroid dysfunction/autoimmunity during pregnancy may lead to similar adverse events, the relationship between 25-hydroxyvitamin D and thyroid parameters was investigated.MethodsSerum samples of 50 women (aged 22 to 36 years) were selected retrospectively. The samples were collected at gestational 8 weeks ±3 days, 20 weeks ±3 days and 32 weeks ±3 days for measurement of 25-hydroxyvitamin D, calcium, phosphate, parathyroid hormone, and thyroid parameters.ResultsThe median 25-hydroxyvitamin D levels were 28.29, 39.23 and 40.03 nmol/L, respectively, from the first to the third trimester. The 25-hydroxyvitamin D concentration during the first trimester was significantly lower than the next two trimesters (p<0.01) and was unchanged between the second and the third trimester. Of these women, 96%, 78% and 76% showed 25-hydroxyvitamin D ≤50 nmol/L during each trimester. Season was associated with 25-hydroxyvitamin D during each trimester (p<0.05), and a significant association was found between calcium and 25-hydroxyvitamin D during the first and the second trimesters. Only triiodothyronine was associated with 25-hydroxyvitamin D in the first trimester (p = 0.024), but statistical significance was only a trend (p = 0.063) after excluding abnormal values. No association was observed between 25-hydroxyvitamin D and phosphate, parathyroid hormone, and other thyroid parameters.ConclusionsVitamin D deficiency during pregnancy was prevalent in women from Northeast China who did not use supplementation. No significant relationships were observed between 25-hydroxyvitamin D and thyroid parameters during pregnancy.

Association Between Maternal Vitamin D Status and Risk of Gestational Diabetes Mellitus in Pregnant Women

“…In agreement with our findings, Marwaha et al (24) have shown no change in 25(OH) D concentrations with progression of pregnancy which could partly be explained by the food products that are not fortified with vitamin D and the absence of current guidelines on recommending mandatory vitamin D supplementation during pregnancy. In a study by Zhao et al (25), the mean level of 25(OH)D in the second trimester was significantly higher than the one in the first trimester and equivalent to the one in the third trimester. Our results are compatible with the recent study which reported high prevalence of severe vitamin D deficiency [25(OH) D<10 ng/mL] (45.6%) among pregnant women in Turkey (26).…”

Correlation of Serum 25-Hydroxyvitamin D and Thyroid Hormones in Pregnant Women in Amman-Jordan

“…As mentioned previously 25(OH) D status is Influenced by many factors [2,11,44] one of these factor is thyroid hormones changes by fetus action causing depletion of TSH, FT4 and FT3 leading to various problems such as placental abruption, miscarriage, fetal growth retardation [49]. Other studies recommended vitamin D supplementation during pregnancy [8,12,25].…”

“…Risk of heart disease and diabetes and their diseases .Vitamin D deficiency and/or VDRs gene polymorphism were associated with many kinds of autoimmune disorders, including type 1 diabetes mellitus, erythematosus systemic lupus, multiple sclerosis rheumatic arthritis [4][5][6][7]. It was reported that vitamin D deficiency associated with autoimmune diseases necessary and supplementation prevents the onset and/ or development of these autoimmune diseases [10,11] which is needed for development of skeletal muscle due to involvement in calcium homeostasis [2,12]. Therefore understanding sources of vitamin D supplementation is vital to reduce risk on mother and fetus.…”

“…Therefore understanding sources of vitamin D supplementation is vital to reduce risk on mother and fetus. Major vitamin D sources is cutanuse synthesis via exposure to sunlight (95%) and dietary intake account for 5% [12]. Moreover vitamin D is a fat-soluble which is stored in body fat and liver [11,12] through complex pathway involve kidney [1,2,12].…”

“…Major vitamin D sources is cutanuse synthesis via exposure to sunlight (95%) and dietary intake account for 5% [12]. Moreover vitamin D is a fat-soluble which is stored in body fat and liver [11,12] through complex pathway involve kidney [1,2,12]. The ultimate conversion of supplemented Vitamin D occurs in the liver to 25-Hydroxyvitamin D which is the most widely accepted indicator of vitamin D because serum 25(OH) D has longer half-life of approximately two to three weeks than 1, 25-(OH) 2 D with a shorter circulating half-life of fifteen hours [2,13] and it is the best indicator of total vitamin D status which is restore from sunlight exposure, diet and conversion from adipose stores in the liver [14,15].…”