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The effect of oral contraceptives on vitamin B12 metabolism. 1979

A M Shojania, and B Wylie

Serum vitamin vitamin B12 levels were determined in 199 women who were on a regimen of oral contraceptives of either the combination or sequential type and in a control group of 196 women. The group using oral contraceptive agents (OCA) had significantly lower serum levels of vitamin B12 vitamin as compared to those of the control group. A total of 19 women using OCAs had serum vitamin B12 levels that were lower than normal values. However, the Schilling test and urinary methylmalonate excretion in this group were normal. The OCA group had a significantly lower total serum vitamin B12 binding capacity, a lower total transcobalamin I level, and a higher transcobalamin III level. Our study suggests that the fall of serum vitamin B12 in OCA users is due to the changes in vitamin B12 binders of serum and does not represent vitamin B12 deficiency. Therefore, according to our data, there is no justification for vitamin B12 supplementation in users of oral contraceptives.

UI MeSH Term Description Entries
D008764 Methylmalonic Acid A malonic acid derivative which is a vital intermediate in the metabolism of fat and protein. Abnormalities in methylmalonic acid metabolism lead to methylmalonic aciduria. This metabolic disease is attributed to a block in the enzymatic conversion of methylmalonyl CoA to succinyl CoA. Acid, Methylmalonic
D003276 Contraceptives, Oral Compounds, usually hormonal, taken orally in order to block ovulation and prevent the occurrence of pregnancy. The hormones are generally estrogen or progesterone or both. Low-Dose Oral Contraceptive,Oral Contraceptive,Oral Contraceptives,Oral Contraceptives, Low-Dose,Oral Contraceptives, Phasic,Contraceptive, Low-Dose Oral,Contraceptive, Oral,Contraceptives, Low-Dose Oral,Contraceptives, Phasic Oral,Low Dose Oral Contraceptive,Low-Dose Oral Contraceptives,Oral Contraceptive, Low-Dose,Oral Contraceptives, Low Dose,Phasic Oral Contraceptives
D003277 Contraceptives, Oral, Combined Fixed drug combinations administered orally for contraceptive purposes. Combined Oral Contraceptive,Contraceptive Agents, Female, Combined,Oral Contraceptives, Combined,Combined Oral Contraceptives,Contraceptive, Combined Oral,Contraceptives, Combined Oral,Oral Contraceptive, Combined
D003279 Contraceptives, Oral, Sequential Drugs administered orally and sequentially for contraceptive purposes. Contraceptive Agents, Female Sequential,Contraceptive Agents, Oral, Sequential,Oral Contraceptive Agents, Sequential,Oral Contraceptives, Sequential,Sequential Oral Contraceptive Agents,Contraceptives, Sequential Oral,Sequential Oral Contraceptives
D003280 Contraceptives, Oral, Synthetic Oral contraceptives which owe their effectiveness to synthetic preparations.
D005260 Female Females
D005492 Folic Acid A member of the vitamin B family that stimulates the hematopoietic system. It is present in the liver and kidney and is found in mushrooms, spinach, yeast, green leaves, and grasses (POACEAE). Folic acid is used in the treatment and prevention of folate deficiencies and megaloblastic anemia. Pteroylglutamic Acid,Vitamin M,Folacin,Folate,Folic Acid, (D)-Isomer,Folic Acid, (DL)-Isomer,Folic Acid, Calcium Salt (1:1),Folic Acid, Monopotassium Salt,Folic Acid, Monosodium Salt,Folic Acid, Potassium Salt,Folic Acid, Sodium Salt,Folvite,Vitamin B9,B9, Vitamin
D005591 Chemical Fractionation Separation of a mixture in successive stages, each stage removing from the mixture some proportion of one of the substances, for example by differential solubility in water-solvent mixtures. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) Fractionation, Chemical,Chemical Fractionations,Fractionations, Chemical
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000042 Absorption The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.

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