Hello, I am in my 8th month now with second baby In my last ultrasound done on 30th week of pregnancy,it shows E.D.D by lmp is 15-09-2021 and E.D.D by USG is 06-09-2021 the earlier ultrasound i had was on 20th week of pregnancy, EDD by lmp - 15-09-2021 EDD by usg - 17-09-2021 Why so kuch difference in due date,earlier it was 17th September and now next ultrasound says due date. around 6th September ??