I'm hoping someone can help me. On another board I frequent, a woman is being told she needs a u/s at 36weeks to determine size of the baby(she is GD). I know that u/s at this late date is notoriously inaccurate, but she wants to know why?? Can anyone tell me WHY it is so inaccurate?? I can give her a ton of examples from my previous client's experience where it was very wrong on size but not the WHY it is so wrong most of the time.
Thank you so much for any help!!