 ART in developed countries is highly expensive one of steps is ovulation induction the most common protocol for induction is the long gonadotrophin-releasing hormone GnRH agonist pituitary suppression regimen combined with relatively high doses of exogenous follicle-stimulating hormone FSH remains the most frequently used stimulation protocol which is expensive. in our study we will use a mild ovarian stimulating protocol letrozole adjuvant to gonadotrophins which is less expensive 