If you switch health insurance plans after your child is born (i.e. the child's birth is a qualifying event, so you decide to change from an HMO to a PPO plan or something like that), my work will backdate the plan change to the date of the qualifying event.

My question is: which plan is the child's hospital care charged to - the new one, since it technically falls after the qualifying event? Or does it count as a continuation of the mother's care from when she was checked into the hospital under the old plan?

If this is something plan specific, should I be contacting Blue Cross Blue Shield or the hospital to figure it out? My HR department doesn't seem to know.