Mouse Model for Combined Oral Contraceptive Administration in Diet

BACKGROUND: Combined oral contraceptives (COCs), containing synthetic estrogen and progestin, are widely used for birth control and managing various conditions. A wide variety of COC formulations are prescribed, yet formulation-specific effects on health remain poorly understood. This study investigated the impacts of two COC formulations––low-dose ethinyl estradiol (EE) with high androgenicity progestin, levonorgestrel (LNG) and high-dose EE and low androgenicity progestin, desogestrel (DSG)––on estrous cycling and anthropometrics in a mouse model. METHODS: Eighteen female C57Bl/6J mice (12 weeks old) were randomized into three groups: low-dose EE + LNG (2mg/kg EE, 200 mg/kg DSG), high-dose EE + DSG (5mg/kg EE, 200 mg/kg DSG) and a control group. Hormones were administered via diet over 8 weeks. Body weight, food intake and estrous cycle stages were monitored, and serum hormone levels were measured at the time of euthanasia. RESULTS: Both COC formulations disrupted estrous cycling, with the EE + LNG group spending more time in diestrus and the EE + DSG group in metestrus, compared to the controls. No significant differences in body weight change or serum progesterone levels were observed, though serum estradiol levels were lower in both experimental groups compared to the control group. CONCLUSION: These findings contribute to the refinement of translational rodent models for COC research and provide insight into the differential effect of the composition of different COC’s.