Hello Your doctor advised clomid 100 mg and you get pregnancy , this time with same drug you didn t get pregnancy . I want to tell you something about clomifene or clomiphene ( clomid ) , this is indicated in anovulatory infertility 50 mg daily for 5 days starting on the 5th day of menstrual cycle or at any time if there is amenorrhea . If ovulation does not occurs a 2nd course of 100 mg fro 5 days may be used commencing as early as 30 days after the previous therapy . Further treatment may not be recommended if pregnancy has not occurred after a total of 6 treatment cycles. This is for your information . As you receive this treatment only one time. 2nd thing you mentioned that you want to take letoval (letrozole ) 2.5 -5 mg . There is no any scientific proof that this help in infertility cases . Letoval is a non steroidal competitive inhibitors of the anomatase enzyme system.It inhibits the conversion of androgen to estrogens. Hope this will help you. In my opinion consult one more infertility specialist and get his opinion.