Medical Journal Article ReviewProgesterone Is Essential for Maintenance and Growth of Uterine Leiomyoma Ishikawa H, Ishi K, Serna VA, Kakazu R, Bulun SE, Kurita T. Endocrinology. 2010 Apr 7
This is a study in which human uterine fibroid tissue was implanted into mice, and the effects of progesterone, estrogen, and anti-progesterone compounds were observed. The authors found that estrogen plus progesterone stimulated growth of fibroid cells, and this growth was blocked with anti-progesterones. Withdrawal of progestrone caused fibroid tissue to shrink. Interestingly, estradiol (estrogen) without progesterone had no effect in this study.
Comment: This study confirms others in showing that progesterone is needed for fibroid growth. For those tempted to use over-the-counter progesterone creams to treat fibroids, this study shows that extra progesterone may cause more harm than good. Do not interpret this study to mean that you shouldn’t take birth control pills if you have fibroids. Certain low dose birth controls do not cause fibroid growth, and may actually slow growth! — Paul Indman, M.D.