Vitamin D and Human Pregnancy

Abstract

At the end of 2007, Time magazine listed the “benefits of vitamin D” as one of its top 10 medical breakthroughs for that year. Since then there has been a remarkable upsurge of interest in vitamin D, with new research advances seemingly published on a weekly basis. In particular, there has been increasing awareness of the variability of vitamin D status in populations across the globe and, significantly, a growing debate about the need for revised parameters for vitamin D supplementation. Although sub-optimal vitamin D is likely to be a widespread problem for 21stcentury societies, it is also clear that some groups are at much greater risk of low vitamin D status. Prominent amongst these are pregnant women and the aim of the following review article will be to discuss this problem in further detail with specific emphasis on its potential physiological and clinical impact.

Vitamin D for Health: A Global Perspective

“…27 The spatiotemporal organization of placental CYP27B1 and the VDR across gestation has also been characterized, confirming that the enzyme and receptor are localized to the maternal and fetal parts of the placenta. 29 Serum levels of DBP increase 46% to 103% during pregnancy, suggesting that DBP may play a role in directing vitamin D metabolism and function during pregnancy. 2,27,30 The DBP has a much higher binding affinity for 25(OH)D than for 1,25(OH) 2 D, and in kidney epithelial cells, DBP plays a pivotal role in conserving 25(OH)D by facilitating the recovery of 25(OH)D from the glomerular filtrate.…”

“…7,25,42 This process results in a reduction of 25(OH)D and 1,25(OH) 2 D levels. 9,29,30 However, during pregnancy, this process becomes uncoupled, resulting in elevated maternal concentrations of circulating 1,25(OH) 2 D. 27,43 The placental methylation of the CYP24A1 promoter reduces the capacity for CYP24A1 induction and down-regulates basal promoter activity and abolishes vitamin D–mediated feedback activation. This epigenetic decoupling of vitamin D feedback catabolism also plays an important role in enhancing 1,25(OH) 2 D bioavailability at the fetomaternal interface.…”

Supplementation of Merino ewes with cholecalciferol in late pregnancy improves the vitamin D status of ewes and lambs at birth but is not correlated with an improvement in immune function in lambs

“…During pregnancy, vitamin D is thought to enhance innate anti-microbial and anti-inflammatory responses within the placenta and reproductive tissues, which may protect the fetus from intrauterine infection and subsequent inflammation (Grayson and Hewison 2011). Maternal transfer of vitamin D to the lamb may occur in utero, or, to a lesser degree, postnatally via intake of milk (Lapillonne 2010).…”

First‐trimester maternal serum 25‐hydroxyvitamin D3 status and pregnancy outcome

“…These aspects have been studied in women from childhood and puberty to old age [1,2]. In addition, vitamin D is involved in implantation and placental development and displays antiproliferative and immunomodulatory actions [3,4]. Low serum 25-hydroxyvitamin D 3 [25(OH)D] levels have been related to adverse obstetric outcomes such as preterm birth, low birth weight, hypertension, and gestational diabetes mellitus (GDM) [3][4][5][6].…”

“…In addition, vitamin D is involved in implantation and placental development and displays antiproliferative and immunomodulatory actions [3,4]. Low serum 25-hydroxyvitamin D 3 [25(OH)D] levels have been related to adverse obstetric outcomes such as preterm birth, low birth weight, hypertension, and gestational diabetes mellitus (GDM) [3][4][5][6]. Cesarean deliveries are 4 times more common among those displaying lower 25(OH)D levels, even after adjustment for confounding factors [7].…”