What Are The Chances Of Pregnancy In Women With Sub Septum Uterus?

Hello there! I am really confused. I ve been TTC for a year and a half now. In one of my first controls after TTC doctor told me I had a regular uterus and everything else in the genital tract, but she was concerned for early or late ovulation, it was the 12th day of MC and no dominant follicle yet. Then I did the 3DAY bloodwork and all parameters were ok. My PAP smear test was negative. I was cleared of all bacterias with antibiotics therapy. Again in the second exam, my doctor told me with ultrasonography that my uterus and ovarians were of regular size and shape. But, yesterday, during the HSG the same doctor told me that now I have a heart-shaped uterus or subseptum uterus. How come she didn t see it before and what do you suggest? She suggested HCG, but she didn t do any measurement of how big the septum is?