<qa>  How many mg does Serum Estradiol level?Serum Estradiol level 150 pgml- No Letrozole; Serum Estradiol Level 150-250 pgml- 2.5mg; Serum Estradiol Level 251-350 pgml- 5 mg; Serum Estradiol Level 350 pgml - 7.5 mg; 