There's quite a bit about Elf Children in HoME X, Morgoth's Ring (well worth getting a copy if you want to know more about Elves!). In here it tells you that Elf children did grow more slowly than children of Men. In Middle-earth, Elves also bred more slowly, avoiding having children during times of trouble for example, so there was less likely to be a population explosion.
Though what the population situation was like in The Undying Lands I shudder to think - I have visions of Galadriel returning there to find it crammed with skyscrapers, the people forced to live in tiny Tokyo style flats and her moaning and saying "it all used to be trees and fields around here".
Maybe they had found a way of shrinking themselves to make more room? In which case I hope Frodo did not contract the Green Death.*
*this may be understood by Vonnegut fans...