My bitch whelped one week ago and is doing great with the litter who are coming on well.  Her first few bowel movements were fine (I expected worst) but they were firm. Yesterday she had a bit of loose stools and this morning there was some mucous (clear) and blood - light coloured withing the mucous.  Any ideas?  She was wormed for 3 weeks last of pregnancy, is vacinatted and otherwise is well in herself, eating well and feeding pups etc. 

brobably just a bit of colitis, one of my dogs gets it occasionaly with no harm done. just feed something like minced beef/chicken/pork high protein mixed with high protein dry food. it should clear up quickly. mine had diarrhorea for a week post giving birth but thats normal whilst licking up the poo

Personally I'd give the vet a ring and talk to them - they'll either tell you not to worry or ask to see her.  Bright blood is less alarming (it's not travelled far so can be just a case of straining, or a scratch) but dark coloured blood I take very seriously - that's travelled further.

My girls tend to be loose after whelping, and I put it down to eating afterbirths (I do try to limit what they eat.)

As someone has already said, she's also cleaning up after pups.  As she was wormed during pregnancy, you know there's no problem there. 

As it's light coloured I think it's likely to be a bit of colitis too.  I'm sure that she would not seem so well in herself, and eating well, if it was something sinister.