You can be sure that in any episode of Call the Midwife, there will be births and there will be babies.
But in the festive special, the midwives' Christmas is set to be interrupted by another kind of drama all together, when an unexploded bomb is found in the East End.
The first trailer for the feature-length episode, which will air on BBC1 on Christmas Day, sees the residents of Poplar being evacuated as their neighbour hood comes under threat.
Meanwhile, Sweet Shelagh (formally Sister Bernadette) is preparing for a quiet wedding to Dr Turner. And impending explosion or not, he's determined that "nothing will stand in the way of this wedding."
Chummy is getting used to life as a new mum, and enjoying it by the looks of things: "I have to say, I feel very like Mary."
And Jenny seems to be finding a little light relief from the drama by settling down in a phone box with Alec and a sprig of mistletoe. A good plan if you ask us!
Watch the trailer:
Call the Midwife is on Christmas Day at 6:15pm on BBC1.