Flexible GnRH antagonist protocol was done with daily s.c administration of cetrorelix 0.25 mg (Cetrotide, Merck Serono, Darmstadt, Germany) started when one or more of the following criteria were achieved: (i) one or more follicle reached 14 mm diameter; (ii) The level of serum E2 reached 600 pg/ml; and (iii) The level of serum LH levels reached 10 IU/l . Daily sc rFSH (Gonal-f; Merck Serono , Darmstadt, Germany) injections was started on 2nd day of the cycle in the antagonist protocol. Continuation of rFSH and GnRH antagonist daily until triggering day was done.