RESUMEN
OBJECTIVE: To present our experience using four consecutive minimal COS (TetraStim) followed by oocyte retrieval and vitrification to increase the number of oocytes in patients with POR for whom oocyte donation is not an option. METHODS: We performed an observational study evaluating 128 poor responders submitted to TetraStim instead of oocyte donation cycles. Patients were submitted to four consecutive minimal COS started at luteal phase, oocyte retrieval, oocyte vitrification/warming, ICSI, endometrial priming and embryo transfer. We evaluated the number of vitrified oocytes, survival rate after warming, fertilization rate, cleavage rate, number of embryos transferred, clinical pregnancy rate, miscarriage rate and live birth rate. RESULTS: The mean age was 38.1 ± 3.1 years. A total of 791 oocytes were recovered (6.1 ± 2.7/patient), 682 (86.2%) Metaphase II (5.3 ± 2.4/patient) were vitrified, 95.3% survived warming (5.1 ± 2.3/patient), 82% showed normal fertilization after ICSI (4.2 ± 2/patient), 79.2% reached cleavage stage (3.3 ± 1.6/patient), 313 cleavage stage embryos were transferred to 115 patients (2.7 ± 0.7/patient) and 14.7% of the patients had surplus embryos that were vitrified. Clinical pregnancy rate per patient was 31.3% and live birth rate per patient was 22.6%. CONCLUSION: To our knowledge this is the first study that demonstrates that TetraStim can be an effective alternative for patients with POR with an indication to perform IVF with donated oocytes, but do not agree to use. TetraStim is a feasible alternative to increase the number of oocytes and embryos and improve pregnancy rates with no dropouts and very low cycle cancelation rate. However, randomized controlled studies must be performed to compare TetraStim with other treatments.