I agree with what the other ladies are saying here. My own babies never arrived on time, and I'm sure by this stage in the game your families have made their arrangements with other caregivers. If it were me, I'd send out an e-mail explaining where you're at, and seeing if it was possible for families to begin their care at the new provider's a week or so early. Take good care of yourself - the last few weeks of a pregnancy are just brutal - and good luck on D-day.