Objective(s): Dehydroepiandrosterone (DHEA) has been reported to improve pregnancy chances in women with diminished ovarian reserve (DOR) and to reduce miscarriage rates by 50–80%. This study, therefore, assesses effects of DHEA on number of retrieved oocytes and meiotic spindles.Materials and Methods: A randomized, prospective, controlled study was conducted on eight groups, four groups of young mice and four elderly. All young and old groups received different oral doses (35, 50, 75 mg/kg) of DHEA for 3 months. Meiotic spindle assessment was done by immunocytochemical techniques using a confocal laser microscope (Leica TCS-4D).Results: Statistical surveys showed that in control young groups 80% (P=0.0845) and in the old control group 73.3% (P=0.000) of the meiotic spindles have a normal shape and structure; the difference was meaningful. The young with 50 mg/kg of DHEA in 85.4% and the young with 75 mg/kg of DHEA in 84.2% were normal in shape and structure. Statistical analysis showed that the difference was meaningless (P=0.845). The old group with 30 mg/kg of DHEA in 81.1%, the old with 50 mg/kg of DHEA in 83.9%, and the old with 75 mg/kg of DHEA in 79.0% showed normal shape and structure. The meiotic spindle disruption ratio in old mice showed a significant difference (P=0.000) in comparison with others in young groups. Statistical analysis showed that difference between DHEA and control groups is meaningful. But this difference was meaningless between DHEA groups.Conclusion: Results showed that DHEA has a positive and improvement effect on the meiotic spindle in old mice
