Ever since we found blood in the Curious Boy's diaper when he was 3 1/2 weeks old, we've paid close attention to what comes out of his butt. Same goes for Zen Girl now. The day we came home from the hospital, the ZG all of two days old, we found blood in her diaper. Not the pretty red uric acid crystals that you learn about in prenatal classes. Drops of blood.
Cue the freakout.
A few deep breath later, PhilosopherMom remebers hearing about a friend's sister who had the same thing early on with one of her newborn girls (she has five, and one on the way). Turns out that estrogen from the mom can cause newborn girls to have a little menstruation.
Closer inspection revealed that ZG had swollen breasts to boot. As many as 10% of little girls have this (LINK).
The spotting stopped later that day.