we have 17 week old twin girls. we moved them into their cot bed about 2 weeks ago as they were running out of room in their Moses basket but in the last week the alarm has gone off on the angelcare monitor for one of the twins 3 times in the last week. She has been fine each time but has moved horizontally she is a bit of a wriggler I am worried sick about why it could be happening she is a happy, healthy 17lb3 baby. We have a bit of plywood underneath and never had any problem when she was in her Moses basket. Has anyone else had this problem?