Exclusively BFing mothers, how old was your babe when your period resumed?
I have just read a GREAT book about this. She comments that 'exclusive breastfeeding' isn't enough...the baby not only needs to be getting all his nutrition from you, but also all his sucking (ie, no binkie). Furthermore, if he's not waking and nursing at night (or not much) then your fertility will probably return too. SO, if you're relying on bf to keep AF at bay, you have to watch those two things very carefully.
The book is older--published in the 70s I think. It's called "Breast Feeding and NAtural Child Spacing: the ecology of natural mothering" by Sheila Kippley. According to her studies, if you follow the bfing rules she lists (basicallywhat I said before) the average time before AF returns is 14 months.