Ovulation block by Pueraria mirifica: a study of its endocrinological effect in female monkeys

Pueraria mirifica (PM), a Thai herb containing phytoestrogens, may act as estrogen and disturb reproduction. To investigate the effect of PM on the menstrual cycle length and related hormones, nine adult female monkeys (Macaca fascicularis) were separated into three groups. Each group (n = 3) was fed with 10, 100, and 1000 mg/d of PM for three menstrual cycles. The menstrual cycle length increased significantly in monkeys treated with PM-10 and PM-100 and disappeared completely in monkeys treated with PM-1000. Serum follicle stimulating hormone, luteinizing hormone, estradiol, progesterone, and irinhibin were lower during the treatment period in a dose-dependent manner. Changes in menstrual cycle length and the hormonal levels recovered during the post-treatment period only in monkeys treated with PM-10 and PM-100. PM greatly influences menstrual cycles and may suppress ovulation by lowering serum levels of gonadotropins.