The aim of this study was to observe the impact of a Lumbosacral Plexus Block (LPB) on sex hormones in female rabbits, in order to elucidate LPB-induced menstrual changes. The blood of selected adult female rabbits was sampled for Estrogen (E), Progesterone (P), Human Chorionic Gonadotropin (HCG), Gonadotropin Releasing Hormone (GnRH), Follicle Stimulating Hormone (FSH), and Luteinizing Hormone (LH), before and after estrus, in order to comprehend the hormonal changes. The level of E in the treatment group was significantly higher than the control group (P<0.05) before and during estrus, but not after estrus (P>0.05). There was no change in the level of P, HCG, GnRH, FSH, and LH between the groups, at any point in the estrous cycle. Thus, LPB increased E before and during estrus, but had no effect on estrogen after estrus. Although LPB also increased the menstrual blood volume, it did not change the menstrual cycle.