10 cm

I feel great consternation when I look at this 10 cm image. On the one hand, I can't believe anything in my body can get that wide. On the other hand, I can't believe that exit door is large enough for a baby.

Susie, the dynamo nurse who runs our Tuesday evening childbirth class, assures us that 10 cm is enough.

"The smallest part of a baby's head is the crown," she says circling the top back part of her skull. "That's the part you hope heads down the canal first. If the child descends face up," she pauses, "that's a little trickier."

I certainly hope Sprout has better head:cervix coordination than I have hand:eye coordination. Otherwise, this birthing thing could be tricky.