I choose blue, but why not use them all-? :)

I'd pick either the red or blue for the sashing, and then use the other in with the nursing fabric for the falling charms. I'd also look for some golds to add, perhaps in a nice daisy floral that we all seem to like so much. I think it will be more effective if you toss in a few different charms even if they are mostly the nursing fabric. Maybe some fun healthy things like apples, carrots, nature (birds, butterflies). Just some ideas.
If just using the nursing fabric alone, I would use the blue for sashing if it's for sleeping, the red if it's for picnics and that kind of use. The blue is much more calming.

I too, like them all but my #1 choice would be the blue. I am not familiar with this pattern but is it possible to use them all.

Another vote for blue!

The blue, it doesn't overwhelm the block.

I like the blue

I like them all as well, but love the red the most and also the beautiful flowered fabric in the back

Really hard to pick but since blue is my favorite color I would choose the blue! Happy quilting :)

I vote for blue also. Cheerful ironing board cover!

I like the blue