Vitamin D, Vitamin A, Maternal-Perinatal Considerations: Old Concepts, New Insights, New Questions
ABSTRACT Vitamins A and D are essential nutrients that play important roles in growth and development. Preterm and low birth weight infants have low levels of these nutrients and are at risk for developing detrimental health consequences associated with vitamin A and vitamin D deficiencies. Preliminary data suggest that vitamin A and D supplementation is needed to prevent deficiency. More work is needed to define optimal doses, timing, and modes of administration to ensure that an adequate supply of these vitamins is available to meet the critical needs during pregnancy and in high-risk neonates.
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ABSTRACT: Serum calcium, inorganic phosphate and heat-labile alkaline phosphatase (HLAP) have been estimated in maternal and cord sera of 120 pregnant women at labour. 75 women who did not take any vitamin D supplements during pregnancy showed statistically significant hypocalcaemia, hypophosphataemia and elevation of HLAP. Hypocalcaemia and hypophosphataemia were present in cord blood, too. 25 women who had received 1,200 U vitamin D/day throughout the 3rd trimester, showed significantly lower HLAP levels and increased fetal birth weight but there was no other improvement in maternal or cord blood chemistry. Administration of vitamin D in two large doses of 600,000 U each in the 7th and 8th months of pregnancy in 20 women proved more efficacious. Statistically significant improvement was observed in all the three biochemical parameters in maternal as well as cord sera. Fetal birth weight was also significantly greater with this mode of therapy.Gynecologic and Obstetric Investigation 02/1981; 12(3):155-61. DOI:10.1159/000299597 · 1.25 Impact Factor
Article: Retinoids as teratogens.[Show abstract] [Hide abstract]
ABSTRACT: Vitamin A is a necessary nutrient in the diet. However, excessive doses of retinoids by pregnant women result in teratogenesis. In this chapter, we initially discuss the occurrence and characteristics of fetal malformations associated with maternal ingestion of natural and synthetic retinoids in both experimental animals and humans. We then turn to an examination of the pharmacology of teratogenic retinoids, focusing on structure-function relationships and pharmacokinetics. Finally, we review the current literature on the molecular mechanism of action of teratogenic doses of retinoids and the role of the retinoic acid receptors and other target genes in this process.Annual Review of Nutrition 02/1995; 15:111-32. DOI:10.1146/annurev.nu.15.070195.000551 · 10.46 Impact Factor
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ABSTRACT: To assess the impact on mortality related to pregnancy of supplementing women of reproductive age each week with a recommended dietary allowance of vitamin A, either preformed or as beta carotene. Double blind, cluster randomised, placebo controlled field trial. Rural southeast central plains of Nepal (Sarlahi district). 44 646 married women, of whom 20 119 became pregnant 22 189 times. 270 wards randomised to 3 groups of 90 each for women to receive weekly a single oral supplement of placebo, vitamin A (7000 micrograms retinol equivalents) or beta carotene (42 mg, or 7000 micrograms retinol equivalents) for over 31/2 years. All cause mortality in women during pregnancy up to 12 weeks post partum (pregnancy related mortality) and mortality during pregnancy to 6 weeks postpartum, excluding deaths apparently related to injury (maternal mortality). Mortality related to pregnancy in the placebo, vitamin A, and beta carotene groups was 704, 426, and 361 deaths per 100 000 pregnancies, yielding relative risks (95% confidence intervals) of 0. 60 (0.37 to 0.97) and 0.51 (0.30 to 0.86). This represented reductions of 40% (P<0.04) and 49% (P<0.01) among those who received vitamin A and beta carotene. Combined, vitamin A or beta carotene lowered mortality by 44% (0.56 (0.37 to 0.84), P<0.005) and reduced the maternal mortality ratio from 645 to 385 deaths per 100 000 live births, or by 40% (P<0.02). Differences in cause of death could not be reliably distinguished between supplemented and placebo groups. Supplementation of women with either vitamin A or beta carotene at recommended dietary amounts during childbearing years can lower mortality related to pregnancy in rural, undernourished populations of south Asia.BMJ Clinical Research 03/1999; 318(7183):570-5. · 14.09 Impact Factor