Gosh, Keiko's hair looks cute like that.
As in Mophead's words, if Ran ever wants to get out of the friendzone, she has to establish a basis for attraction, because Keiko doesn't seem to be attracted romantically to Ran at all. She's just comfortable with her around (no more bad dreams and no more loneliness).
Since you don't think there's any romantic attraction on Keiko's part, I was wondering how you interpreted the whole honmei choco scene? Because it struck me as pretty dang romantic, with her blushing and all. Their interactions can sometimes feel like a middle ground between platonic and romantic, but that scene definitely isn't one of them.
As for the child thing, we actually don't know if Keiko can have one anymore. A miscarriage with complications may well make her unable to ever bear child again. Which would explain her pushing her boyfriend away.
Could be the case, but it didn't seem like there were any complications, plus she's still young and healthy. Usually infertility isn't even considered until you've had more than two miscarriages consecutively. Still, the risk for a recurrence is higher once you've had one. I don't know if she could go through that again :(
