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Updated: Jan 15, 2026

Fertility Preservation Through Oocyte Vitrification: Clinical and Laboratory Perspectives
Published on: September 16, 2021
Efficiency of mild ovarian stimulation with letrozole co-treatment in expected low ovarian responders
Alfredo Cortés-Vazquez1, Ismael Perez-Bautista1, J Andreas Mejicanos-Quiñonez1
1Reproductive Endocrinology Department, Centro Médico Nacional 20 de Noviembre, Mexico City, Mexico.
Objective:
Ovarian stimulation (OS) is a critical step in assisted reproductive techniques (ART); it has been routinely adopted since it substantially increases the whole process efficiency. Our study aims to compare the efficiency of mild OS with letrozole co-treatment vs. conventional OS in expected low ovarian responders.
Methods:
A single-centre, observational, comparative, non-experimental and retrospective study using our database at the Reproductive Endocrinology Department at Centro Médico Nacional 20 de Noviembre in Mexico City was performed.
Results:
We compared the total rFSH dosage per oocyte, we noticed a statistically significant difference between groups, Group A 388.9 vs. Group B 667.2IU per retrieved oocyte (p<0.0002, 105 to 450 IU CI 95%), Comparing total rFSH dosage per follicle, we noticed a statistically significant difference among Group A 397.5 vs. Group B 590.2IU per follicle (p<0.014, 39.2 to 346.2 IU, CI 95%).
Conclusions:
In expected poor ovarian responders, mild ovarian stimulation with letrozole co-treatment is much more efficient than conventional stimulation.
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