Lowering Low Density Lipoprotein Cholesterol with Simvastatin, a Hydroxy-3-Methylglutaryl-Coenzyme A Reductase Inhibitor, Does Not Affect Luteal Function in Premenopausal Women

In this double-blind, randomized, placebo-controlled study, normally cycling women (n = 86) with elevated low density lipoprotein cholesterol (LDL-C) levels were studied over six menstrual cycles. At the end of the screening phase, participants received placebo for the second menstrual cycle and subsequently were randomized to receive either placebo or simvastatin (40 mg/d) for the next four cycles. The second and sixth menstrual cycles were considered baseline and treatment cycles, respectively. Participants kept a menstrual diary throughout the study and provided daily first-void urine samples during cycles 2 and 6. Urine samples were assayed for LH and pregnanediol glucuronide (PdG). The primary end point was change in luteal phase duration as defined by the day of the urinary LH peak to the day preceding the onset of menstruation. Treatment with simvastatin (40 mg/d) effectively lowered LDL-C by 34.3% (P < 0.001). Simvastatin was generally well tolerated, and no meaningful difference in adverse event profile was observed between treatment groups. Compared with the placebo group, simvastatin did not have clinically relevant effects on luteal phase duration, peak PdG concentration, or integrated luteal phase PdG concentration. The results of this study demonstrate that treatment of healthy premenopausal women for approximately 4 months with simvastatin (40 mg/d) lowers LDL-C without adversely affecting reproductive gonadal function. Simvastatin should not be used during pregnancy or by nursing mothers.