Progesterone, one of the most important hormones for pregnancy and for regulating menstrual periods, is normally found in synthetic form in birth control pills. Some alternative practitioners advocate taking natural progesterone in addition to birth control pills to counteract some of the common side effects. Some suggest using creams derived from yams, which may not actually contain any progesterone at all. Because this is a controversial issue with many divergent opinions espoused by different experts, ask your medical practitioner before taking any other form of progesterone along with birth control pills.
Birth control pills contain progestins, synthetic progesterone that changes the uterine lining to make embryo implantation difficult. Progestins also block the actions of luteinizing hormone, necessary for maturation of an egg and keep cervical mucus thick, which makes it difficult for sperm to reach the uterus and fallopian tubes, where fertilization occurs. Birth control pills may contain either progestins alone of a combination of progestins and synthetic estrogen, which interferes with egg development. Natural progesterones in prescription creams and pills have identical effects to progesterone produced each month by the body. Over-the-counter creams often contain diosgenin, a plant substance that can be converted to progesterone in the lab, but not in your body. These creams have no progesterone-like benefits unless they have progesterone added, which some over-the-counter creams do.
According to some alternative practitioners such as author David Zava, Ph.D., using natural progesterone when taking birth control pills can help improve the annoying symptoms that often occur with birth control pills. Typical birth control pill side effects include weight gain, depression, nausea, breast tenderness and headaches.
On the other hand, the Progesterone Research Network quotes medical practitioner John Lee, M.D., as saying that natural progesterone and birth control pills should not be taken together. The website Endo-Resolved states that natural progesterone will compete with synthetic progesterone for receptor sites. This can interfere with the effect of birth control pills, increasing the chance you may get pregnant, according to Dr. Lee.
Most women, but not all, who take the birth control pill are taking it as contraception. If you're taking the pill for contraception, using natural progesterone as well might increase your chances of pregnancy. If you're taking birth control pills as hormone replacement therapy or to reduce endometriosis, abnormal growth of uterine tissue outside the uterus, consider changing to natural progesterone. Instead of trying to take both types of progesterone, Endo-Resolved recommends gradual weaning off the synthetic form. Talk with your doctor before changing medications, since there may be a reason he prefers the synthetic form for you. Do not take over-the-counter progesterone supplements, which aren't well regulated and which may contain varying amounts of progesterone.