Anti-implantation and uterotonic properties of Mentha pulegium L. in female Sprague-Dawley rats

Background: Some traditional herbs disrupt endocrine-endometrial synchrony, affecting embryo-endometrium communication during fertility. Hormonal imbalances cause non-receptive conditions, leading to anti-implantation or abortion. Historically, Mentha pulegium has served for contraceptive and abortive purposes. Its effects on the post-coital contraceptive and hormonal activities were evaluated. Methods: Thirty-six Sprague-Dawley female rats were selected based on the presence of copulation plugs and received 200, 500, and 1000 mg/kg of Hydroethanolic leaf extract of Mentha pulegium L. (MPE) for seven days. Reproductive organ weights and serum estrogen and progesterone levels were measured. The resorption index, anti-implantation activity, and pre-implantation loss were also calculated using the number of implantation sites and resorptions in all treatments. Data were presented as mean±standard error mean (SEM), and significance was defined as p<0.05 using one-way ANOVA. Results: Post-coital administration of MPE resulted in resorptive, pre-implantation loss, and anti-implantation activity. A dose of 200 mg/kg reduced the number of implantations and exhibited a high resorption index, percentage pre-implantation loss, and anti-implantation activity. A marked decline in serum progesterone levels and a significant reduction in serum estrogen and progesterone ratio was observed at 200 mg/kg MPE. A significant increase in uterine weight was observed in the 500 mg/kg treatment. Doses of 500 and 1000 mg/kg resulted in a significant reduction in anti-implantation activity. Conclusions: The observed anti-implantation activity and pre-implantation loss suggest the abortifacient properties of MPE. However, its effects were seen to be dose-dependent.