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

Abstract

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.

Vitamin B12 Deficiency and the Role of Gender: A Cross-Sectional Study of a Large Cohort

“…Nonetheless, hormonal replacement therapy did not alter serum vitamin B12 levels [30, 31]. Although several studies reported that oral contraceptives decreased serum vitamin B12 levels, there is currently no concrete evidence for any such influence [32]. Even if endogenous estrogen somehow plays a protective role, it seems that the findings of the current study cannot be solely explained by estrogen.…”

Determinants of neural tube defect (NTD)-protective circulating concentrations of folate in women of child-bearing age in the US post-folic acid fortification era

“…Our results demonstrated that women who use hormonal contraceptives were significantly more likely to have SP concentrations of plasma folate, especially among SU. Even though a number of earlier studies have reported that contraceptives negatively impact folate status, presently available data do not support this conclusion [40]. The reduction in estrogen content in contraceptives over time [41], relatively lower negative effect of contraceptives on absorption of synthetic FA compared to natural folate [42] or the availability of contraceptive pills containing FA [43] may explain these observations.…”

Role of vitamin B6 in idiopathic burning mouth syndrome: some clinical observations

“…Reactional feedback mechanisms can be evoked since vitB6 deficiency was first reported in women taking high-dose contraceptives [37], and several other studies showing abnormal vitB6 levels in women taking both oral contraceptives and menopausal hormone replacement therapy have been interpreted as indicating estrogeninduced vitB6 deficiency or depletion [38]. It should also be kept in mind that BMS is not a homogeneous entity and several lines of evidence suggest the existence of different subgroups [5,39,40].…”