Water soluble vitamins in Pregnancy

During pregnancy, serum vitamin C progressively decreases by approximately 50% (Drife), partly because of the extra uptake by the fetus (Kazzi) and partly due to hemodilution [i]. The RDA for vitamin C in pregnancy are 67% higher that that for nonpregnant, nonlactating women (See table 1).

Low concentrations of Vitamin C were observed in preeclamptic patients in South Africa[ii]. Sharma et al[iii], and Clemetson and Cafaro [iv] report an associateion between the incidence of abruptio placentae and low vitamin C concentration but no intervention trials have been done looking at status and antepartum hemorrhage.

Routine use of large doses of ascorbic acid in amounts > 1g/d is not recommended [v].

Vitamin B1 (Thiamine)

Plasma thiamine also declines during pregnancy (Kazzi). Thiamin dietary allowances are 12% higher in early pregnancy because of increased requirements associated with pregnancy and remain constant throughout [vi]. Although rare, thiamine deficiency can occure where stable food is polished rice [vii].

Prophylactic thiamine fortification of diet or pharmaceutical supplementation is desirable to avert neonatal death where deficiency is known to exist (Blegen).

Vitamin B2 (Riboflavin)

Riboflavin levels have also been shown to decline during pregnancy (Kazzi). Its dietary allowances are 7% higher because of increased maternal and foetal tissue synthesis and a small increase in energy utilisation (Ref 5(v)).

Riboflavin deficiency can occur as a result of extra demand by the fetus, cooking losses, and inadequate dietary intakes, and biochemical deficiency has been reported in pregnant women [viii]. The deficiency affects the immune reponse by decreasing antibody responses, thymic weight, and circulating lymphocyte number (Yoshida).

Vitamin B2 supplementation can improve the hematologic response to iron[ix] and, where deficiency is common, supplementtion is needed to restore biochemical normality[x],[xi].

Vitamin B3 (Niacin)

Evidence suggests that niacine concentrations decrease during pregnancy (Kazzi), whereas urinary excretion of niacin metabolism increases. Niacine dietary allowances are 10% higher despite a possibility that bioconversion from tryptophan may increase as a result of increased energy requirements[xii].

Vitamin B6 (Pyridoxine)

Vitamin B6 concentrations decline during pregnancy as a physiologic adjustment secondary to increased blood volume or as a result of increased requirements for active transport across the placenta [xiii](Institute of Medicine) ref 5(ii).

Pyridoxine deficiency rarely occursalone and is often associated with deficiency in several B-complex vitamins[xiv]. Nevertheless, vitamin B-6 has been associated with preeclampsia, carbohydrate intolerance, hyperemesis gravidarum, and neurologic disease of infants. [xv],[xvi],[xvii],[xviii]. Vitamin B-6 deficiency also affects immunity by reducing lymphocyte numbers and the proliferative reponses to mitogen, lymphoid tissue weights, graft rejection, interleukin-2 production, delayed-type hypersensitivity reacations, and antibody responses.

Folate (Folinic Acid)

Folate concentrations have been shown to decline during pregnancy as a result of decreased intestinal absorption, inadequate intake, or increased demand [xix].

Folate deficiency are due to inadequate dietary intakes, cooking habits that exacerbate losses, food taboos, inadequate food storage, and intense erythroid hyperplasia in the bone marrow (eg. Sickle cell anemia, chronic hemolytic anemia, or homozygous beta thalassemia); deficiency is associated with megaloblastic anemia, low birth weight, and potential foetal anomaly [xx],[xxi],[xxii].

In West Africa, the frequency of megaloblastic anemia was reduced by 50% after antimalarial prophylaxis and it was completely abolished with folate supplementation[xxiii].

The administration of folic acid in the periconceptional period reduces the number of births with neural tube defects by 75%[xxiv]; thus, folic acid administration is recommended as standard prenatal care by the International Nutritional Anemia Consultative Group [xxv]. In countries where dimorphic and megaloblastic anemias are common, prophylactic medication with folic acid should be added to the routine iron medication that all pregnant mothers require [xxvi]. Except for women taking anticonvulsant drugs, who may have coexisting vitamin B-12 deficiency, there is no evidence that folate supplementation in pregnancy is unsafe. [xxvii]

Vitamin B12 (Cobalamine)

Vitamin B12 concentration progressively decline during pregnancy, which may be independent of dietary intakes and may not represent decreased maternal stores or deficiency at the biochemical level [xxviii].

Vitamin B-12 deficiency is rare in pregnancy. It is however associated with megaloblastic anemia in preganancy as reported in

Zimbabwe

and

India

(Savage), [xxix] and low blood concentration were observed in

Mexico

[xxx]. Deficiency in pregnancy can lead to intrauterine death and possibly to adverse infant neurobehavioural development [xxxi]. Vitamin B-12 deficiency depresses phagocyte functions, delayed-type hypersensitivity responses, and T-Cell proliferation (Yoshida).

References

[i] Hytten FE. Nutrition. In: Hytten F, Chamberlain G, eds. Clinical physiology in obstetrics. Oxford , United Kingdom : Blackwell Scientific Publications, 1980:163–92.

[ii] Bowen RS, Mars M, Chuturgoon AA, Dutton MF, Moodley J. The response of the dietary antioxidants vitamin E and vitamin C to oxidative stress in pre-eclampsia. J Obstet Gynecol 1998;18: 9–13.

[iii] Sharma SC , Walzman M , Bonnar J , Molloy A. Blood ascorbic acid levels and histamine levels in patients with placental bleeding. Hum Nutr Clin Nutr 1985;39C:233–8.

[iv] Clemetson CAB, Cafaro V. Abruptio placentae. Int J Gynecol Obstet 1981;19:453–60.

[v] National Research Council. Recommended dietary allowances. 10^th ed. Washington , DC : National Academy Press, 1989.

[vi] Heller S, Salkeld RM, Korner WF. Vitamin B1 status in pregnancy. Am J Clin Nutr 1974:27:1221–4.

[vii] Blegen SD. Postpartum congestive heart failure, beriberi heart disease. Acta Med Scand 1965;178:515–24.

[viii] Powers HJ. Effects of riboflavin deficiency on the handling of iron. In: Micronutrient interactions: impact on child health and nutrition. Washington , DC : ILSI Press, 1998:36–42.

[ix] Powers HJ. Effects of riboflavin deficiency on the handling of iron. In: Micronutrient interactions: impact on child health and nutrition. Washington , DC : ILSI Press, 1998:36–42.

[x] Bates CJ, Prentice AM, Paul AA. Seasonal variation in vitamin A, C, riboflavin and folate intakes and status of pregnant and lactating women in a rural Gambian community: some possible implications. Eur J Clin Nutr 1994;48:660–8.

[xi] Bates CJ, Prentice AM, Watkinson M , et al. Efficacy of a food supplement in correcting riboflavin deficiency in pregnant Gambian women. Hum Nutr Clin Nutr 1984;38C:363–74.

[xii] Institute of Medicine . Nutrition during pregnancy. Washington , DC : National Academy Press, 1990.

[xiii] Institute of Medicine . Dietary reference intakes. Thiamin, riboflavin, niacin, vitamin B-6, folate, vitamin B-12, pantothenic acid, biotin, and choline. Washington , DC : National Academy Press, 1998 (prepublication edition).

[xiv] National Research Council. Recommended dietary allowances. 10^th ed. Washington , DC : National Academy Press, 1989.

[xv] Spellace WN, Buti SC, Birk SA. Vitamin B6 treatment of gestational diabetes mellitus: studies of blood glucose and plasma insulin. Am J Obstet Gynecol 1977;127:599–602.

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

[xvii] Pitkin RM. Vitamins and minerals in pregnancy. Clin Perinatol 1975;2:221–32.

[xviii] Nichols BL , Nichols VN . Nutritional physiology in pregnancy and lactation. Adv Paediatr 1983;30:473–515.

[xix] Czeizel AB. Folic acid in the prevention of neural tube defects. J Pediatr Gastroenterol Nutr 1995;20:4–16.

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[xxi] Qvist I, Abdulla M, Jagerstad M, et al. Iron, zinc and folate status during pregnancy and two months after delivery. Acta Obstet Gynecol Scand 1986;65:15–22.

[xxii] Bruinse HW, Vander Berg H, Haspels AA. Maternal serum folacin levels during and after normal pregnancy. Eur J Obstet Gynecol Reprod Biol 1985;20:153–8.

[xxiii] Savage D, Gangaidz O, Lindenbaum J, et al. Vitamin B12 deficiency in the primary cause of megaloblastic anaemia in Zimbabwe. Br J Haematol 1994;86:844–50.

[xxiv] Department of Health, Scottish Office, Home and Health Department, Welsh Office, Department of Health and Social Services, Northern Ireland. Folic acid and the prevention of neural tube defects: report from an expert advisory group. London : Department of Health, 1992.

[xxv] Stoltzfus RJ, Dreyfuss ML. Guidelines for the use of iron supplements to prevent and treat iron deficiency anemia. Washington , DC : INACG/WHO/UNICEF, 1998.

[xxvi] Lawson JB , Stewart D. Obstetrics and gynecology in the tropics and developing countries. London : Edward Arnold Ltd, 1970.

[xxvii] Wickramasinghe SN. Folate and B-12 deficiency and supplementation. Prescribers J 1997;37:88–95.

[xxviii] Metz J, McGrath K, Bennett M, Hyland K, Bottinglieri T. Biochemical indices of vitamin B12 nutrition in pregnant patients with subnormal serum vitamin B12 levels. Am J Hematol 1995;48:251–5.

[xxix] Baker SJ, Jacob E, Rajan KT, Swaminathan SP. Vitamin B12 deficiency in pregnancy and puerperium. Br Med J 1962;1: 1658–61.

[xxx] Allen L. The nutrition CRSP: what is marginal malnutrition and does it affect human function? Nutr Rev 1993;1:255–67.