Talk to Gynecologist on Lmp Date And Ultrasound

First pregnancy , one missed abortion history in early weeks , two times ultrasound hua h dono me lmp date se days two days km aye Hein , first u/s me bhi do din km or dusry me bhi or do din km .. aesa kyun h? According to lmp 12 week hain or ultrasound me 4 days already km thy , ab next ultrasound July me Hona h , koi khatry ki BAAT hy ye? Lmp 26 march