about the 10 mins thing...
some of the posters sounded like they thought it was for a scheduling thing, or so the girl could bf and then eat, or something like that. like several other posters, I am also a teacher and my experience is that lunch periods are getting shorter and shorter. my guess (and yes, i know it's just a guess, but still...) is that by the time the girl walks from her class to the daycare, stopping to grab food from the cafeteria or locker, finds her child, picks up her child, settles down to nurse, and unwraps her sandwich, her lunch period is finished. she probably thinks the 10 mins will allow her the time she needs to get there and back.
i mean, think about it- the baby is probably nursing for at least 20 mins, right? when my dd was little, every nursing session was at least 30 minutes. it took her a really long time to drink bottles of pumped milk too.
anyway, so 20 mins to nurse, add in the time to greet your child, say goodbye to your child, walk from one side of a building to the other and back again, etc, etc. the daycare center might even be one where she is "encouraged" to change her child's diaper after the feedings. there's no way anyone could do that in the amount of time most schools provide for lunch these days.
like the other teachers who have posted, i agree that other students get to leave class frequently for a variety of other reasons, and that is expected to be ok with the teacher. also, you never introduce new material that late in a period. for the last 10 minutes, students are typically finishing up with independent work (which the girl could complete as extra homework) and you're trying to provide some sort of closure to the lesson to make sure the material stuck.
i also want to say that i agree completely with the pp about the tone of this thread. i am very much against teenage pregnancy. that being said, if a teenager gets pregnant, she needs to be encouraged to make the right decisions for herself and her child. right now, it sounds like this girl is really trying to do a good job. staying in school is what's best for her, and breastfeeding is what's best for her baby. there is no reason why those two goals should be at odds. whether we made better decisions or worse, whether we had it easier or harder, we should always work to support a mother who wants to do what's best for her child.