The comparison of effect of four different treatment protocols: Antagonist/letrozole protocol, microdose flare-up protocol, Antagonist/clomiphene protocol, Antagonist on IVF outcomes in poor responders undergoing in vitro fertilization; a prospective randomized-controlled study.

Inclusion Criteria:

Criteria for definition of poor responders included at least one of the following

1. Anti müllerian hormone <1.1 ng/ml and/or a previous poor ovarian response (≤3 oocytes with a conventional stimulation protocol).
2. Primary infertile patients
3. BMI≤30 kg/m2 were included this study.

Exclusion Criteria:

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