Isoflavones in soybeans are phytoestrogens, plant estrogens that have estrogen-like properties. Isoflavones have gained popularity on Internet forums as a method of inducing ovulation if you're having trouble getting pregnant. Proponents of this technique claim that isoflavone act similarly to the prescription drug clomiphene citrate, brand name Clomid, used to induce ovulation. There is no scientific evidence that this method works; any evidence is purely anecdotal. Ask your doctor before taking isoflavone supplements to increase your chances of getting pregnant, since soy can have a negative effect on fertility.
Actions
Phytoestrogens can bind to estrogen receptors in tissues. They can act either as weak estrogens or as anti-estrogens, blocking the effects of estrogen. Soy isoflavones may have similar effects to clomiphene, a drug that can have estrogenic and anti-estrogenic effects. Clomiphene induces ovulation by fooling your body into thinking that it isn't producing enough estrogen, so the ovaries produce more. Women substituting soy isoflavones for Clomid are taking the supplements like they would Clomid, for just five days at the beginning of the menstrual cycle to stimulate egg production.
Negative Studies
The only clinical studies on isoflavones and pregnancy rates are negative, showing that soy hurts rather than helps your chances of pregnancy. A review of studies conducted by the University of Minnesota and reported in the March 2002 issue of "The Journal of Nutrition" found that soy isoflavone ingestion in amounts between 32 and 200 mg per day was associated with decreased levels of the reproductive hormones estrogen and progesterone, both necessary for a healthy pregnancy.
Risks
Soy isoflavone supplements may vary in their composition and the amount of active drug they contain, according to the Linus Pauling Institute. In a University of Cincinnati College of Medicine study reported in the April 2001 "Journal of Nutrition," the actual amount of isoflavones differed by 10 percent compared to the amount listed on the packaging in 50 percent of products tested. Supplements are not as well-regulated as drugs in the United States. Women taking soy supplements for infertility should not take them throughout the entire menstrual cycle or they may not ovulate, according to JustMommies.
Considerations
Numerous studies have shown mixed results on the benefits of soy isoflavones on other estrogen-related conditions such as estrogen-dependent tumors and menopause symptoms. The precise actions of soy isoflavones have yet to be determined. Until clinical trials prove that soy isoflavones demonstrate benefit in improving fertility and establish a safe dosage, the stories of positive pregnancy tests while taking soy isoflavones remain merely anecdotal.
References
- Linus Pauling Institute; Soy Isoflavones; Jane Higdon; January 2006
- "The Journal of Nutrition"; Hormonal Effects of Soy in Premenopausal Women and Men; Mindy Kurzer; March 2002
- "The Journal of Nutrition"; Bioavailability of Pure Isoflavones in Healthy Humans and Analysis of Commercial Soy Isoflavone Supplements; K. Setchell, et al.; April 2001
- Drugs.com: Clomid
- JustMommies: Soy Isoflavones: Natural Alternative to Clomid
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