
I would make 100% sure you have a vet you know and trust who is on alert from the 19-20th Dec as you do not want to be rushing to find a vet out of hours last moment. Especially over the christmas period. Have you welped a litter before? I only ask as you were unsure of the due date which made me think you may not have.
Have you got everything you need as again over the Xmas time it may not be easy to suddenly have to obtain milk suppliment or bottles if hand feeding in required or heat pads etc..
Good luck Aileen