I've had some worrying news yesterday at my 20 week scan, that my little girls head is falling under the 5th centile. It is off the chart. Her AC is on the 90th and femur length is 30th. One of my previous was born with a head around the 40th and one was born on the 90th. I've been told to wait for a call back from fetal medicine and to try and not worry, which of course I am. Has anyone else experienced this?