Scans are fairly accurate (from ovulation) But bubs can measure bigger (some babies are just big) I knew exactly when I ovulated after working it out...I only had sex once that month...:) But my girl always measured 2-3 weeks ahead (I make big babies) xxx

@sara-lou, you tend to be bigger 2nd pregnancy I'm huge but measuring a week a head but that's only cos I see my midwife on a Tuesday so I'm +5 on my weeks then x

I felt much bigger second pregnancy. They check babies size though so they'd know if baby was measuring bigger.