Maternal vitamin D status during pregnancy: the Mediterranean reality

Abstract

Vitamin D status during pregnancy is linked to bone mineralization of developing fetus, which justifies targeting sufficient levels of vitamin D in pregnant women. Despite high level of sunshine in the Mediterranean regions, maternal hypovitaminosis D remain common in these countries. The aim of this narrative review was to provide potential explanations for this phenomenon in an effort to guide future public health policies and vitamin D intakes during pregnancy. We searched Medline for publications regarding hypovitaminosis D during pregnancy in the Mediterranean region. Available studies confirmed the high prevalence of hypovitaminosis D among pregnant women in the Mediterranean regions (50-65% in most studies), resulting in severe skeletal and nonskeletal health events among the offspring. Reasons for this may rely on maternal darker skin pigmentation, poor dietary vitamin D intake, veiled clothing and reduced sunshine exposure, health policies and increased prevalence of obesity. Public health organizations should be aware of this phenomenon and develop specific policies to prevent hypovitaminosis D and its adverse outcomes in maternal and neonatal health. INTRODUCTIONPregnancy comprises a critical time frame in which the growing fetus is under the influence of a plethora of exogenous and endogenous factors. These factors have been hypothesized to be involved in lasting changes in the body composition, the physiology and the metabolism of the offspring. One of the biological factors is maternal vitamin D status during pregnancy. Maternal hypovitaminosis D during pregnancy has been related to several neonatal and maternal adverse health outcomes. 1 On physiological basis, the developing fetus primarily obtains the necessary amounts of vitamin D for bone mineralization and other functions through adequate maternal stores. 2 Therefore, optimizing maternal vitamin D status during pregnancy has been proposed by health organizations and nutrition specialists as the most efficient method for the prevention of this condition. 3,4 Inspite of current recommendations, 3,4 several cross-sectional observational studies conducted across Europe, including the Mediterranean regions, have shown a very high prevalence of pregnant populations with vitamin D deficiency. It is all the more surprising in that nutritional sources provide only o10% of the daily requirement of vitamin D, 3,4 the remainder coming from the synthesis of vitamin D in the skin under the effect of solar radiation. The phenomenon of a just as similar or even higher prevalence of maternal vitamin D deficiency during pregnancy in southern European countries compared with central or northern ones warrants further investigation. This article aimed at listing possible explanations for this phenomenon in an effort to guide future public health policies and vitamin D intakes during pregnancy, while also providing a

ENDOCRINOLOGY IN PREGNANCY: Bone metabolic changes during pregnancy: a period of vulnerability to osteoporosis and fracture

“…It may be speculated, therefore, that further increases in the levels of vitamin D might translate into a more efficient calcium transfer at the intestine. The point is of interest, because the prevalence of vitamin D insufficiency, including the population of pregnant women, is elevated (8), even in low-latitude countries, where sun exposure is high (9). In this context, it may be conceived that a potential role exists for vitamin D analogs, as these compounds are designed to increase the effects of vitamin D while minimizing pathological hypercalcemia (10).…”

Significant of Serum 25-Hydroxyvitamin D and Thyroid Hormones Levels in Pregnant Women in Jordan

“…The 25(OH)D is metabolized in the kidneys by the enzyme 25-hydroxyvitaminD-1a-hydroxylase (CYP27B1) to active form 1,25-dihydroxyvitamin D [1] this product is tightly regulated by plasma levels parathyroid hormone, calcium and phosphorus levels [6]. Vitamin D concentration >30.0 ng/ml (>75,0 nmol/L considered to be sufficient, insufficient level is between 20 and 30ng/mL (50-75nmol/L) and deficient if it is <20ng/mL (<50nmol/L) [7][8].There are many factors influence Vitamin D levels in the body such as geographical zones, dietary patterns, physical environment, seasons, dark skin pigmentation and obesity [9][10].…”

Vitamin D and Female Reproduction

“…Observational studies have shown consistent associations between obstetrical clinical outcomes and poor maternal vitamin D status, including preeclampsia, gestational diabetes, low birth weight, increased cesarean section rate, neonatal asthma, seizures, and preterm labor [73][74][75].…”