In Vivo Antifertility Effects of Aqueous Extract of Carica papaya Unripe Fruit in Female Wistar Rats: Safety Profiling and Hormonal Correlates

Unripe Carica papaya fruit preparations are used widely across Nigerian communities as traditional contraceptives, particularly among women in Ogun, Oyo, and Osun States, South West Nigeria. Despite centuries of ethnomedicinal use, controlled in vivo investigations of antifertility mechanisms and associated safety profiles of oral preparations remain limited. This study evaluates the antifertility effects of aqueous extract of unripe Carica papaya fruit administered orally to female Wistar rats, with concurrent hormonal and hepatotoxicity profiling. Female rats were administered extract doses of 200, 400, and 600 mg/kg daily for 30 days during the active reproductive cycle. Reproductive outcome parameters included implantation rate, litter size, post-implantation loss, and uterine weight. Serum concentrations of oestrogen, progesterone, luteinising hormone, and follicle-stimulating hormone were measured by ELISA. Liver enzymes and histopathology were assessed for hepatotoxic safety monitoring. The 400 and 600 mg/kg dose groups showed significant reductions in implantation rate and litter size. Hormonal profiling revealed significant suppression of oestrogen and LH at higher doses, suggesting hypothalamic-pituitary-ovarian axis disruption. Hepatotoxicity markers were significantly elevated at 600 mg/kg, indicating dose-limiting liver safety concerns. These results confirm antifertility activity of unripe papaya extract but highlight a narrow safety margin, necessitating further work before contraceptive formulation development. Keywords: Carica papaya, antifertility, contraceptive, hormonal profiling, hepatotoxicity