Birth control pills are contraceptives that use female hormones to alter a woman's normal menstrual cycle. The pill prevents pregnancy by blocking ovulation, so your ovaries do not release an ovum that can be fertilized and lead to pregnancy. Vitamin C, or ascorbic acid, is typically found at relatively high levels within your ovaries, suggesting the vitamin proves important to ovary functioning. Consuming very high levels of vitamin C might affect ovary function and disrupt the normal function of the birth control pill; however, its specific effect on contraceptive pill efficacy remains largely unknown.
Effect on Estrogen
Consuming high levels of vitamin C might have an effect on the efficacy of the birth control pill due to an interaction with estrogen, one of the hormones present in several types of birth control pills. Ascorbic acid can lead to an increase in circulating estrogen in your body, explains the University of Maryland Medical Center. Regulating estrogen levels during each birth control pill cycle proves important to effectively blocking ovulation. If vitamin C is taken at doses sufficient to significantly disrupt estrogen levels in your body, this might affect the efficacy of the pill.
Possible Effect on Progesterone
Vitamin C can also interact with progesterone -- another hormone found in birth control pills -- in some cases. A study published in "Fertility & Sterility" in 2003 found that vitamin C supplementation could increase progesterone levels in women suffering from luteal phase defect, a condition that causes infertility. Although these data suggest that vitamin C can affect progesterone levels to prevent disease-related infertility, it is not yet known whether this interaction also affects the progesterone levels in women taking birth control pills.
Overall Effect on Birth Control
Though vitamin C can interact with some of the hormones found in several forms of birth control, its overall effect on birth control efficacy is still largely unknown. Go Ask Alice!, a health service by Columbia University, indicates that while moderate doses of vitamin C -- and other vitamins -- are unlikely to significantly affect birth control, taking very large doses might decrease the pill's efficacy.
To prevent an adverse reaction between vitamin C supplements and the birth control pill, consume vitamin C in moderation. Many individuals that follow a healthy diet, consuming several servings of vegetables and fruits per day, might not require supplemental vitamin C intake at all. The University of Maryland Medical Center recommends that men consume 90 mg of ascorbic acid daily, women consume 75 mg, and breastfeeding women consume 120 mg per day. If you take birth control, talk to your doctor before taking any vitamin supplements, including vitamin C.