Hi Suryaprabha Welcome to HealthcareMagic I would like to know your endometrial thickness on the day of ovulation. For successful pregnancy it should be atleast 7 mm. If endo thickness is persistently less during IUI cycles then you should undergo diagnostic hysteroscopy ( where uterine cavity is directly visualized using a camera ) and also endometrial biopsy need to be taken to rule out tuberculosis. If everything comes out to be normal then there are certain medicines which can be used to improve endo thickness with mixed success like estradiol valerate, arginine, vit E , pentoxyphylline , sildenafil. You can discuss options with your treating doctor. You can proceed for one or two more cycle of IUI with stimulation by gonadotropin injections instead of clomiphene . If these treatment also fail then IVF and surrogacy are last options. For husband s problem IUI with donor sperms can be done. All the best .