Lipid Soluble Vitamins in Pregnancy

Blood vitamin A concentration decline gradually in pregnancy because of hemo-dilution, and evidence exists that inadequate dietary vitamin A intake can also lower blood concentrations. [i]

Vitamin A deficiency is widespread and occurs when the intake of dairy products and carotene-rich vegetables and fruit is limited and, occasionally, with malabsorption syndrome. Vitamin A deficiency in pregnancy is known to result in:

Vitamin A deficiency reduces leukocyte numbers, lymphoid tissue weights, complement, T cell functions, tumor resistance, natural killer cell numbers, antigen-specific immunoglobulins G and E, and T_H2 numbers and increases interferon γ synthesis.

Weekly vitamin A supplementation in Nepal reduced maternal mortality by 40%, the prevalence of subclinical vitamin A deficiency by 84% (West KP), and the risk of night blindness by 38% [vii]. Vitamin A is associated with anaemia [viii],[ix] and supplementing pregnant women in their second trimester with both vitamin A and iron daily for two months improved haemoglobin concentrations more so than did supplementation with iron or vitamin A alone [x].

Hypervitaminosis A increases the risk of fetal malformations and supplementation should not exceed 3000 µg/d [xi]. Excess vitamin A also has adjuvant effects that increase lymphocyte proliferation, tumor resistance, graft rejection, and cytotoxic T cell activity, possibly by inhibiting T cell apoptosis.

Vitamin D

The active metabolite of blood vitamin D (1,25-dihydroxycholecalciferol ) increases during pregnancy whereas the inactive form (25-hydroxcholecalciferol) decreases [xii]. Vitamin D deficiency is rare , but neonatal tetany, foetal rickets, and abnormal teeth development have been reported in areas where Vitamin D deficiency is present [xiii].

Daily low doses are preferable to a few large doses because the risk of toxicity is reduced.

Vitamin E & K

Vitamin E concentrations are known to increase during gestation, probably because of the hyperlipidemic state associated with pregnancy [xiv]. Deficiency is rare except in malabsorption syndrome, but low concentrations have been associated with abruptio placentae in normal pregnancies.

Vitamin K deficiency is also rare. Nevertheless, pregnant women taking an oral anticoagulant (e.g. coumadin) are at increased risk of hemorrhage because of the antagonist effect of the anticoagulant on vitamin K[xv].

References

[i] Wallingford JC, Underwood BA. Vitamin A deficiency in pregnancy, lactation, and the nursing child. In: Bauernfeind JC , ed. Vitamin A deficiency and its control. New York : Academic Press, 1986:101–52.

[ii] Katz J, Khatry SK , West KP, et al. Night blindness is prevalent during pregnancy and lactation in rural Nepal . J Nutr 1995;125:2122–7.

[iii] Christian P , West KP, Khartry SK , et al. Night blindness of pregnancy in rural Nepal : nutritional and health risks. Int J Epidemiol 1998;27:231–7.

[iv] West KP, Katz J, Khatry SK , et al. Double blind, cluster randomized trial of low dose supplementation with vitamin A or b-carotene on mortality related to pregnancy in Nepal . Br Med J 1999;318:570–5.

[v] Ramakrishnan U, Manjrekar R, Rivera J, Gonzalez-Cossio T, Martorell R. Micronutrients and pregnancy outcome: a review of the literature. Nutr Res 1999;19:103–59.

[vi] Sharma SC , Bonnar J , Dostalova L. Comparison of blood levels of vitamin A, b-carotene, and vitamin E in abruptio placentae with normal pregnancy. Int J Vitam Nutr Res 1986;56:3–9.

[vii] World Health Organization. Requirements of ascorbic acid, vitamin D, vitamin B-12, folate, and iron. World Health Organ Tech Rep Ser 1972;452.

[viii] Meija LA, Chew F. Hematological effect of supplementing anemic children with vitamin A alone and in combination with iron. Am J Clin Nutr 1988;48:595–600.

[ix] Bloem MW, Wedel M, Van Agtmaal EJ, Speeck AJ, Saowakontha S, Schreurs WHP. Vitamin A intervention: short term effects of a single, oral, massive dose on iron metabolism. Am J Clin Nutr 1990;51:76–9.

[x] Suharno D, West CE, Muhilal, Karyadi D , Hautvast JGAJ. Supplementation with vitamin A and iron for nutritional anaemia in pregnant omen in West Java, Indonesia. Lancet 1993;1: 1593–6.

[xi] World Health Organization. Safe vitamin A dosage during pregnancy and lactation. Geneva : WHO, 1998. [WHO/NUT/98.4.]

[xii] Moghissi KS . Risks and benefits of nutritional supplements during pregnancy. Obstet Gynecol 1981;58:685–785.

[xiii] Roberts SA, Cohen MD, Farfar JO. Antenatal factors associated with neonatal hypocalcaemia convulsions. Lancet 1973;12:809–11.

[xiv] Wickens D ,Wilkins MH, Lyne CJ , et al. Free radical oxidation (peroxidation) products in plasma in normal and abnormal pregnancy. Ann Clin Biochem 1981;18:158–62.

[xv] Drife J , MacNab G. Mineral and vitamin supplements. Clin Obstet Gynaecol 1986;13:253–67.