Oral Contraceptives and Folate Metabolism

Shojania, A. Majid; Hornady, G; Barnes, PhilipH.

doi:10.1016/s0140-6736(69)91923-0

Cited by 33 publications

(7 citation statements)

References 3 publications

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“…The remaining controls were hospital staff and wives or friends of laboratory staff. In Yorkshire subjects and controls were matched for oral contraceptive usage since this may influence folate absorption (Shojania & Hornady 1973), but it proved impossible to match southern England subjects. Neither subjects nor controls had taken vitamin supplements in the three months prior to the study.…”

Section: Methodsmentioning

confidence: 99%

Investigation of folate intake and metabolism in women who have had two pregnancies complicated by neural tube defects

Wild

Seller

Schorah

et al. 1994

BJOG

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Object To investigate folate intake and blood levels of folic acid and vitamin C in women with and without a history of two NTD‐affected pregnancies and to measure the increase in serum folate following ingestion of orange juice. Subject Sixteen women with a history of two NTD‐affected infants and 16 controls with no such history, none of whom were either pregnant or taking vitamin supplements. The orange juice loading test was carried out on eight matched pairs. Main outcome measures Dietary intake of folate was assessed by questionnaire and blood levels of folate and vitamin C were measured. Results There was no evidence of decreased intake of folate in subjects who had had two NTD‐affected pregnancies. In controls, both serum and red cell folate showed significant correlation with dietary folate, while in subjects there was no such correlation. Subjects also had smaller increases in serum folate following an oral load than controls, although the differences were not significant. Conclusion Women who have had two NTD‐affected pregnancies may have defective folate metabolism. Further investigations on short term utilisation of ingested food folates in these women are required.

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Section: Methodsmentioning

confidence: 99%

Investigation of folate intake and metabolism in women who have had two pregnancies complicated by neural tube defects

Wild

Seller

Schorah

et al. 1994

BJOG

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“…An alternative proposed mechanism for impaired folate status in OC users is that OCs may increase the clearance of folate from blood, 68,69 possibly as a result of changes in liver enzymes or renal folate‐binding proteins involved in reabsorption in the kidney 70 . Shojania and Hornady 69 reported an increase in plasma clearance of polyglutamyl folate in OC users during the first few minutes following a test dose. Increased urinary excretion of intact folate was observed in OC users compared with non‐users during a 12‐hour collection following an intravenous folic acid injection 53 .…”

mentioning

confidence: 99%

Oral contraceptive use: impact on folate, vitamin B6, and vitamin B12 status

et al. 2011

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Since many unplanned pregnancies occur while women are using oral contraceptives (OCs), it is important to understand the potential impact of these drugs on folate, vitamin B₆ , and vitamin B₁₂ status. Although a number of early studies concluded that OCs negatively impact folate status, the majority of these studies were conducted when the estrogen content of OCs was much higher. In addition, the interpretation of findings from many of these studies is problematic since no controls were included for potentially confounding factors. The presently available data do not support a conclusion that currently used OCs negatively impact folate status. In regard to vitamin B₆ , however, existing population-based data do provide evidence that current low-dose OCs may negatively impact vitamin B₆ status. The observed depression in plasma pyridoxal 5'-phosphate concentrations in OC users may reflect decreased body reserves of the vitamin, which could put women who discontinue OCs and become pregnant at risk for vitamin B₆ inadequacy during pregnancy. Functional indicators of vitamin B₁₂ status are not significantly impacted by OC use. Definitive conclusions, however, await further investigations.

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“…Reduced serum folate concentrations have been reported in women using oral contraceptives [109]. The absorption of polyglutamates, the major food source containing folic acid, is reduced in oral contraceptive users, but monoglutamate absorption is normal.…”

Section: Folic Acid and Vitamin B 12mentioning

confidence: 99%

Metabolic effects of combined oral contraceptives

Gillmer¹

1989

Contraception

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Oral Contraceptives and Folate Metabolism

Cited by 33 publications

References 3 publications

Investigation of folate intake and metabolism in women who have had two pregnancies complicated by neural tube defects

Investigation of folate intake and metabolism in women who have had two pregnancies complicated by neural tube defects

Oral contraceptive use: impact on folate, vitamin B6, and vitamin B12 status

Metabolic effects of combined oral contraceptives

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