<\/p>\n\n\n\n
Uterine fibroids (UFs) are one of the most prevalent benign abnormal cell growth diseases worldwide, with approximately 80% of premenopausal women experiencing their symptoms of heavy menstrual bleeding, pain, and infertility, according to a study<\/a> published in the journal Medicina<\/em> [1]. Here we cover UF treatment with a class of medications called selective progesterone receptor modulators (SPRMs), better known as emergency contraceptives.<\/p>\n\n\n\n In a previous article (found here<\/a>) looking at the relationship between hormonal birth control and uterine fibroids<\/a>, we covered the conflicting reports on whether or not Hormonal Birth Control (HBC) reduces fibroid risk.\u00a0 Per that article, the fact that \u201cthere are currently 259 different formulations of hormonal birth control on the market\u201d likely contributes to a lack of conclusive evidence on whether HBC can, in fact, reduce fibroid risk. Additionally, \u201cthe conflicting reports may be a result of the wide variety of concentrations of estrogen and\/or progestin in each medication.\u201d\u00a0<\/p>\n\n\n\n While progesterone<\/a> is a vital hormone for women\u2019s reproductive health (maintaining and preparing the uterine lining<\/a> for a fertilized egg, sustaining the early stages of pregnancy<\/a>, as well as other day-to-day functions like blood sugar regulation), if progesterone levels become abnormally low or the body becomes less sensitive to the progesterone it produces, a host of reproductive issues can appear. <\/p>\n\n\n\n Progesterone resistance<\/a> happens when the body becomes less and less sensitive to the progesterone it produces, much like insulin resistance in Type II Diabetes. While researchers are still not sure what causes progesterone resistance, it is clear that it leads to reproductive issues like infertility, miscarriage, endometriosis<\/a>, PCOS<\/a>, and uterine fibroids. <\/p>\n\n\n\n At the cellular level, disrupted progesterone signaling affects the body in ways that can lead to all the aforementioned reproductive issues; oftentimes the disrupted signaling itself is a result of decreased sensitivity in the progesterone receptor. To reference a helpful image from our previous look at uterine fibroids and hormonal birth control: imagine your cells as little houses with mailboxes on the outside. These mailboxes are cell receptors. These cell receptors are special proteins that sit on the surface of the cell and wait for specific messages like a mailbox slot that will only accept letters\u2013in this case, only progesterone \u201cletters.\u201d <\/p>\n\n\n\n The progesterone resistance at the receptor level can affect cells in many ways, including:<\/p>\n\n\n\n Enter selective progesterone receptor modulators (SPRMs), man-made compounds found in emergency contraceptives like Mifepristone<\/a> and Ella that compete with progesterone at the progesterone receptor binding sites, selectively turning progesterone signals “on” or “off” depending on where in the body they\u2019re acting. These SPRMs have been shown to prevent cell growth by targeting fibroid cells and inducing programmed cell death by turning these signals \u201coff\u201d [2]. <\/p>\n\n\n\n Note that while Plan B or the \u201cmorning-after pill\u201d (also known by the drug name levonorgestrel) is<\/em> an emergency contraceptive, it is a progestogen (a synthetic form of progesterone that acts similarly to naturally made progesterone in the body) and \u201cfeeds\u201d the progesterone receptors. In contrast, SPRM\u2019s \u201cstarve\u201d the receptors [4]. For this reason, Plan B would not be taken as a uterine fibroid treatment. <\/p>\n\n\n\n While most commonly used as an emergency contraceptive<\/a> by either preventing ovulation or terminating a very early pregnancy<\/a>, SPRMs are used in clinical practice to treat PMS, abnormal uterine bleeding, and endometriosis, for breast cancer prevention, and, of course, to treat uterine fibroids [3].<\/p>\n\n\n\n There are 5 types of SPRM\u2019s commonly used in clinical practice\u2013Mifepristone (also known as Mifeprix or the abortion pill)<\/a>, Ulipristal Acetate (sold under the brand name Ella or ellaOne), Asoprisnil, Telapristone Acetate (sold under the names Proellex and Progenta), and Vilaprisan. Let\u2019s take a look at the two most popular ones, keeping in mind that all SPRMs perform in relatively the same way. (If you\u2019d like to read about all 5 types, check out the meta-analysis published in the medical journal Cells <\/em>here<\/a>.)<\/p>\n\n\n\n A 2023 comprehensive review of literature<\/a> examined the role of progesterone in uterine fibroid growth as well as pharmaceutical approaches to modulate UF growth [3]. <\/p>\n\n\n\n One study in the review examined 42 women with symptomatic uterine fibroids over the course of 26 weeks. These women were split into two groups\u2013one group taking 2.5 mg of mifepristone per day, the other group taking 5 mg\/day. At the end of the 26 week study, 78% of women in the 2.5 mg\/day group experienced therapeutic amenorrhea<\/a> (more on this below), or the absence of menstruation, and on average the fibroid volume decreased by 27.9%. In the group of women taking 5 mg\/day, 94% experienced amenorrhea and they had a 45.5% decrease in fibroid volume. The side effects were rather mild between the 2.5 and 5 mg\/day groups, with 9 and 16% respectively reporting hot flashes, 2 and 4% respectively experiencing nausea or vomiting, and liver enzymes elevated in 13 and 7% respectively (an important finding, as SPRMs have been correlated with liver toxicity) [3].<\/p>\n\n\n\n Note that while in healthy<\/em> women, amenorrhea is seen as a symptom of a serious disorder, in women with UFs, induced amenorrhea has been used as a therapeutic treatment: UFs often lead to heavy menstrual bleeding, pelvic pain, iron-deficiency anemia, and cramps. Inducing temporary amenorrhea may also help reduce fibroid size, since it leads to lower levels of estrogen (see our HBC and Fibroid article<\/a> for more information)<\/p>\n\n\n\n Ulipristal acetate (UPA) is the most well-known and most tested SPRM. However, chronic use of UPA is also known for causing liver toxicity, abnormal liver enzymes, and in rare cases, liver failure [3].\u00a0 In fact, UPA is no longer able to be marketed in Europe for use as fibroid treatment (Esmya | European Medicines Agency (EMA)<\/a>).<\/p>\n\n\n\n A rigorous four-part study was performed on the effect of UFs, using UPA in what\u2019s called the PEARL (PGL4001 Efficacy Assessment in Reduction of symptoms because of uterine Leiomyomata) trials [5]. Women with symptomatic UFs seeking surgery were randomly divided into three groups: 96 women were given 5 mg UPA per day, 98 were given 10 mg\/day, and 48 received a placebo. <\/p>\n\n\n\n After 13 weeks, 91% of women taking 5mg\/day saw a decrease in uterine bleeding using an objective assessment called pictorial blood-loss assessment chart (PBAC). 92% of women on 10 mg\/day saw a decrease in bleeding, and only 19% of women on the placebo reported a decrease. For women on 5mg\/day, 73% experienced amenorrhea compared to 82% of women taking 10 mg\/day, and compared to only 6% of women on the placebo. For total fibroid volume, women on 5 mg\/day saw a 21% decrease in size, women on 10 mg\/day saw a 12% decrease, and women on the placebo saw growth<\/strong> of 3% [5]. <\/p>\n\n\n\n As with any medication we put into our bodies, there are always side effects. The liver toxicity risks of SPRMs can be life-threatening, likely caused because progesterone (and therefore also the SPRMs bound to the progesterone receptors) are broken down by the liver. Ulipristal acetate was used by over 765,000 women in Europe between 2012 and 2018: five women were diagnosed with drug-induced liver injury, four of whom required a liver transplant [6]. <\/p>\n\n\n\n To put this in context, UPA used for uterine fibroids is only one-sixth<\/em> of the dosage used for the abortion pill, yet after the long-term course of treatment at about 12 weeks long, it\u2019s strongly recommended to monitor liver function for up to four weeks after the end of the treatment to make sure liver function remains normal [7]. Mifepristone (the abortion pill) can be anywhere from 300mg to 1200 mg daily, with one study finding that after 2-3 months on the higher end of the dosage, women were starting to show signs of liver injury, including severe, long-lasting jaundice [8].<\/p>\n\n\n\n Unlike the lack of conclusive evidence in our look at HBC and uterine fibroids<\/a>, it seems quite clear that emergency contraception, specifically SPRMs, dramatically improve uterine fibroid size as well as the negative side effects of the growths like heavy menstrual bleeding and painful cramps. However, the amount of research on SPRM\u2019s as a long-term treatment has been halted due to very real concerns of liver toxicity. <\/p>\n\n\n\n It\u2019s also important to point out that SPRMs induce amenorrhea, or the cessation of periods, and women need <\/em>healthy, regular periods for optimal health and well-being<\/a>. SPRMs are also unhelpful to the woman struggling with fibroids who wants to get pregnant now or in the future. An ideal treatment would therefore address the root cause of fibroids, restoring a woman\u2019s natural cycle, and preserving her fertility. <\/p>\n\n\n\n In forthcoming articles, we will address research on plant-based treatments for uterine fibroids, as well as the various surgical approaches used to address fibroids. <\/p>\n\n\n\n This article updated on 11\/27\/2025<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"Aseg\u00farate de sopesar los pros y los contras\u00a0","protected":false},"author":129,"featured_media":22797,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":true,"_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","csco_singular_sidebar":"","csco_page_header_type":"","csco_page_load_nextpost":"","csco_post_video_location":[],"csco_post_video_url":"","csco_post_video_bg_start_time":0,"csco_post_video_bg_end_time":0,"footnotes":""},"categories":[5550,5326],"tags":[6090,6397,59,6343],"class_list":{"0":"post-22796","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-birth-control-side-effects","8":"category-perimenopause-and-menopause","9":"tag-emergency-contraception","10":"tag-heavy-menstrual-bleeding","11":"tag-infertility","12":"tag-uterine-fibroids","13":"cs-entry","14":"cs-video-wrap"},"acf":[],"yoast_head":"\nUterine fibroids and hormonal birth control recap<\/span><\/h2>\n\n\n\n
The problem of progesterone when it comes to uterine fibroids<\/span><\/h2>\n\n\n\n
\n
Selective progesterone receptor modulators (SPRMs) as a treatment for uterine fibroids<\/span><\/h2>\n\n\n\n
A word about Plan B and uterine fibroids<\/span><\/h3>\n\n\n\n
SPRMs aren\u2019t just used for \u2018emergency contraception\u2019<\/span><\/h2>\n\n\n\n
Mifepristone (aka the abortion pill)<\/span><\/h3>\n\n\n\n
Ulipristal Acetate (UPA)<\/span><\/h3>\n\n\n\n
Comparing liver damage risks with UPA for uterine fibroids vs. liver damage risks with the abortion pill<\/span><\/h3>\n\n\n\n
The bottom line: what\u2019s the best treatment for uterine fibroids?<\/span><\/h2>\n\n\n\n
References<\/span><\/h4>\n\n\n\n[1] Kwas, K., Nowakowska, A., Fornalczyk, A., Krzycka, M., Nowak, A., Wilczy\u0144ski, J., & Szubert, M. (2021). Impact of Contraception on Uterine Fibroids. Medicina (Kaunas, Lithuania)<\/em>, 57<\/em>(7), 717. https:\/\/doi.org\/10.3390\/medicina57070717<\/p>\n\n\n\n[2] Piecak, K., Milart, P., Wo\u017aniakowska, E., & Paszkowski, T. (2017). Ulipristal acetate as a treatment option for uterine fibroids. Przeglad menopauzalny = Menopause review<\/em>, 16<\/em>(4), 133\u2013136. https:\/\/doi.org\/10.5114\/pm.2017.72792<\/p>\n\n\n\n[3] Ali, M., Ciebiera, M., Vafaei, S., Alkhrait, S., Chen, H.-Y., Chiang, Y.-F., Huang, K.-C., Feduniw, S., Hsia, S.-M., & Al-Hendy, A. (2023). Progesterone Signaling and Uterine Fibroid Pathogenesis; Molecular Mechanisms and Potential Therapeutics. Cells<\/em>, 12<\/em>(8), 1117. https:\/\/doi.org\/10.3390\/cells12081117<\/a><\/p>\n\n\n\n[4] Vincent, P., & Hazell, T. (2025, May 7). Emergency contraceptives<\/em>. Emergency Contraception | Types and Uses | Doctor. https:\/\/patient.info\/doctor\/emergency-contraception-pro#progestogen-only-emergency-contraceptive-levonorgestrel <\/p>\n\n\n\n[5] Donnez, J., Tatarchuk, T. F., Bouchard, P., Puscasiu, L., Zakharenko, N. F., Ivanova, T., Ugocsai, G., Mara, M., Jilla, M. P., Bestel, E., Terrill, P., Osterloh, I., & Loumaye, E. (2012). Ulipristal acetate versus placebo for fibroid treatment before surgery. New England Journal of Medicine<\/em>, 366<\/em>(5), 409\u2013420. https:\/\/doi.org\/10.1056\/nejmoa1103182 <\/p>\n\n\n\n
References Continued<\/span><\/h4>\n\n\n\n[6] Donnez, J. (2018). Liver injury and ulipristal acetate: An overstated tragedy? Fertility and Sterility<\/em>, 110<\/em>(4), 593\u2013595. https:\/\/doi.org\/10.1016\/j.fertnstert.2018.06.044 <\/p>\n\n\n\n[7] Gatti, M., Poluzzi, E., De Ponti, F., & Raschi, E. (2020). Liver Injury with Ulipristal Acetate: Exploring the Underlying Pharmacological Basis. Drug safety<\/em>, 43<\/em>(12), 1277\u20131285. https:\/\/doi.org\/10.1007\/s40264-020-00975-8<\/p>\n\n\n\n[8] LiverTox: Clinical and Research Information on Drug-Induced Liver Injury [Internet]. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012-. Mifepristone. [Updated 2018 Mar 10]. Available from: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK548328\/<\/p>\n\n\n\n