Chasteberry, also known as vitex or monk's pepper, has been used extensively throughout history as a treatment for disorders affecting the female reproductive system. In modern naturopathy, practitioners recommend chasteberry to treat disorders including infertility, breast pain and premenstrual syndrome. Chasteberry's impact on reproductive hormones renders it inappropriate for women using hormonal contraceptives. Supplements containing chasteberry could reduce the efficacy of contraceptives or increase the risk of hormone-related side effects.
Hormonal Effects
The Memorial Sloan-Kettering Cancer Center reports that chasteberry possesses estrogenic effects. It appears to increase levels of estrogen, a hormone that governs female fertility, thus impacting the function of the breasts, ovaries and uterus. Sloan-Kettering also notes that chasteberry contains precursors to other reproductive hormones, including progesterone, testosterone, luteinizing hormone, follicle-stimulating hormone, prolactin and androstenedione. Chasteberry's hormonal effects may account for its purported ability to increase fertility and treat hormone conditions.
Drug-Herb Interaction
Hormonal contraceptives depend upon elevated levels of estrogen and/or progesterone to prevent ovulation and fertilization. Examples of hormone-based birth control options include "the Pill," the progestin IUD, the ring, the patch and the shot. In theory, chasteberry could either augment or counteract the effects of hormone-based birth control. The National Center for Complementary and Alternative Medicine recommends that all women using hormone-based birth control avoid chasteberry supplements, since both products affect levels of reproductive hormones.
Safety and Side Effects
MayoClinic.com attributes the common side effects of birth control to elevated levels of estrogen and progesterone. Because chasteberry could further increase levels of these hormones, it may increase the risk of side effects such as headache, nausea, weight gain and breast tenderness. Chasteberry is well-known as a fertility aid and may encourage ovulation -- negating the effects of contraception. Women using hormonal birth control in conjunction with chasteberry may experience unplanned pregnancy.
Prevention
Women using hormone-based contraceptives should not take chasteberry. If a health care provider recommends the use of chasteberry for a fertile woman of reproductive age, she should use an alternate, hormone-free form of contraception -- such as condoms, withdrawal, spermicide or abstinence -- to prevent an unplanned pregnancy. Always defer to the judgment of a qualified expert before combining herbal supplements with any prescription drug.
