Minimal stimulation protocol using letrozole versus microdose flare up GnRH agonist protocol in women with poor ovarian response undergoing ICSI

Background: To compare the IVF outcomes of letrozole/antagonist and microdose GnRH agonist flare up protocols in poor ovarian responders undergoing intracytoplasmic sperm injection. Materials and methods: A randomized controlled trial was performed in patients with one or more previous failed IVF cycles in which four or less oocytes were retrieved when the gonadotrophin starting dose was at least 300 IU/day. Sixty patients were randomized by computer-generated list to receive either letrozole/antagonist (mild stimulation) n = 30 or GnRH-a protocol (microdose flare) n = 30. Results: Both groups were similar with respect to background and hormonal characteristics (age, duration of infertility, BMI, FSH, LH and E2). The clinical pregnancy rate per cycle was similar in both groups (13.3 vs. 16.6%; OR = 0.769; 95% CI = 0.185, 3.198). The doses of used gonadotropins and the number of stimulation days were significantly lower in the letrozole/antagonist protocol. The peak E2 level on the day of hCG, the endometrial thickness, the retrieved oocytes, the number of fertilized oocytes, the number of transferred embryos and the cancellation rate were statistically similar in both groups. Conclusions: The letrozole/antagonist protocol is a cost-effective and patient-friendly protocol that may be used in poor ovarian responders for IVF/ICSI.