Effects of Simvastatin on Uterine Leiomyoma Size

Inclusion Criteria:

* Signed informed written consent.
* Gender: female.
* Age: 18-55 years at time of signing consent.
* BMI of subjects: \< 45 kg/m2.
* Uterine fibroids:
* Diagnosed by ultrasound (MRI will be used only if ultrasound is inconclusive).
* Number: any number of fibroids.
* Location: submucosal or intramural.
* At least one fibroid of diameter \> 3cm.
* Symptoms: one or more of the following symptoms of heavy menstrual bleeding (HMB), defined as: Experienced cyclic (22 to 35 days) abnormal uterine bleeding (heavy or prolonged) in at least 3 of the last 6 menstrual periods, including menstrual bleeding lasting 5 or more days or heavy bleeding per participant recall. Examples of heavy bleeding may include, but are not limited to the following:
* Requires the use of double protection to manage menstrual bleeding.
* Menstrual bleeding accompanied by the sensation of "gushing" or "flooding".
* Saturates more than 1 tampon or sanitary pad per hour for 3 or more consecutive hours.
* Regularly needs to change the tampon or sanitary pad at night or regularly soils bedclothes.
* Heavy bleeding that affects work, school, or social activities.
* Pelvic pain/ pressure likely caused by fibroids.
* Plan for surgery (hysterectomy or myomectomy).
* Normal Pap smear within the last year.
* Use of contraception during study such as non-hormonal oral contraceptives, intrauterine devices (IUD)/ intrauterine systems (IUS), barrier contraceptives, abstinence or sterilization.

Exclusion Criteria:

* Pregnancy or lactation.
* Previous or current uterine, cervical or ovarian cancer.
* Current endometrial hyperplasia or history of atypical endometrial hyperplasia. Endometrial biopsy will be done during screening (if not done within last 12 months).
* Suspicion of leiomyosarcoma.
* Recent rapid growth of fibroids (i.e. doubling in size within 1-6 months period).
* Unevaluated gynecologic abnormalities (unexplained vaginal bleeding, cervical dysplasia, or abnormal adnexal/ovarian mass).
* Menopausal status.
* Surgery is urgently indicated (\< 3 months) for medical or social reasons.
* Hemoglobin ≤ 6 g/dL.
* Currently enrolled in another investigational study.
* Mental condition or other barrier preventing informed written consent.
* Allergy or hypersensitivity to simvastatin.
* Current use of simvastatin or other drugs of the same class.
* Concomitant administration of strong CYP3A4 inhibitors including itraconazole, ketoconazole, posaconazole, voriconazole, erythromycin, clarithromycin, telithromycin, HIV protease inhibitors, boceprevir, telaprevir, nefazodone, and cobicistat-containing products.
* Concomitant administration of gemfibrozil, cyclosporine, or danazol, verapamil, diltiazem, amiodarone, diltiazem, dronedarone, amlodipine, ranolazine, lomitapide, and grapefruit juice.
* Active liver disease, which may include unexplained persistent elevations in hepatic transaminase levels.( elevation of aspartate transaminase and/or alanine transaminase \> 2 s.d. above the normal range at screening visit)
* Known increased risk or diagnosis of a myopathy.