Risk Factor: A*
Class: Vitamins

Contents of this page:
Fetal Risk Summary
Breast Feeding Summary

Fetal Risk Summary

Niacinamide, a water-soluble B complex vitamin, is an essential nutrient required for lipid metabolism, tissue respiration, and glycogenolysis (1). Both niacin, which is converted to niacinamide in vivo, and niacinamide are available commercially and are collectively known as vitamin B3. The National Academy of Sciences’ recommended dietary allowance for niacin in pregnancy is 17 mg (1).

Only two reports have been located that link niacinamide with maternal or fetal complications. A 1948 study observed an association between niacinamide deficiency and pregnancy-induced hypertension (PIH) (2). Other B complex vitamins have also been associated with this disease, but any relationship between vitamins and PIH is controversial (see other B complex vitamins). One patient with hyperemesis gravidarum presented with neuritis, reddened tongue, and psychosis (3). She was treated with 100 mg of niacin plus other B complex vitamins, resulting in the rapid disappearance of her symptoms. The authors attributed her response to the niacin.

Niacinamide is actively transported to the fetus (4,5). Higher concentrations are found in the fetus and newborn, rather than in the mother (5,6,7 and 8). Deficiency of niacinamide in pregnancy is uncommon except in women with poor nutrition (6,7). At term, mean niacinamide values in 174 mothers were 3.9 g/mL (range 2.07.2 g/mL) and in their newborns 5.8 g/mL (range 3.010.5 g/mL) (6). Conversion of the amino acid tryptophan to niacin and then to niacinamide is enhanced in pregnancy (9).

[*Risk Factor C if used in doses above the RDA.]

Breast Feeding Summary

Niacin, the precursor to niacinamide, is actively excreted in human breast milk (10). Reports on the excretion of niacinamide in milk have not been located, but it is probable that it also is actively transferred. In a study of lactating women with low nutritional status, supplementation with niacin in doses of 2.060.0 mg/day resulted in mean milk concentrations of 1.172.75 g/mL (10). Milk concentrations were directly proportional to dietary intake. A 1983 English study measured niacin levels in pooled human milk obtained from mothers of preterm (26 mothers, 2934 weeks) and term (35 mothers, 39 weeks or longer) infants (11). Niacin in milk from preterm mothers rose from 0.65 g/mL (colostrum) to 2.05 g/mL (16196 days), whereas that in milk from term mothers increased during the same period from 0.50 to 1.82 g/mL.

The National Academy of Sciences’ recommended dietary allowance (RDA) for niacin during lactation is 20 mg (1). If the diet of the lactating woman adequately supplies this amount, supplementation with niacinamide is not needed. Maternal supplementation with the RDA for niacinamide is recommended for those patients with inadequate nutritional intake.



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  2. Hobson W. A dietary and clinical survey of pregnant women with particular Reference to toxaemia of pregnancy. J Hyg 1948;46:198216.
  3. Hart BF, McConnell WT. Vitamin B factors in toxic psychosis of pregnancy and the puerperium. Am J Obstet Gynecol 1943;46:283.
  4. Hill EP, Longo LD. Dynamics of maternal-fetal nutrient transfer. Fed Proc 1980;39:23944.
  5. Kaminetzky HA, Baker H, Frank O, Langer A. The effects of intravenously administered water-soluble vitamins during labor in normovitaminemic and hypovitaminemic gravidas on maternal and neonatal blood vitamin levels at delivery. Am J Obstet Gynecol 1974;120:697703.
  6. Baker H, Frank O, Thomson AD, Langer A, Munves ED, De Angelis B, Kaminetzky HA. Vitamin profile of 174 mothers and newborns at parturition. Am J Clin Nutr 1975;28:5965.
  7. Baker H, Frank O, Deangelis B, Feingold S, Kaminetzky HA. Role of placenta in maternal-fetal vitamin transfer in humans. Am J Obstet Gynecol 1981;141:7926.
  8. Baker H, Thind IS, Frank O, DeAngelis B, Caterini H, Lquria DB. Vitamin levels in low-birth-weight newborn infants and their mothers. Am J Obstet Gynecol 1977;129:5214.
  9. Wertz AW, Lojkin ME, Bouchard BS, Derby MB. Tryptophan-niacin relationships in pregnancy. Am J Nutr 1958;64:33953.
  10. Deodhar AD, Rajalakshmi R, Ramakrishnan CV. Studies on human lactation. Part III. Effect of dietary vitamin supplementation on vitamin contents of breast milk. Acta Paediatr Scand 1964;53:428.
  11. Ford JE, Zechalko A, Murphy J, Brooke OG. Comparison of the B vitamin composition of milk from mothers of preterm and term babies. Arch Dis Child 1983;58:36772.

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