My periods came back both times about 5-6 weeks after the birth (lucky me!) and then continued with annoying regularity! ;P (despite fulltime breastfeeding, both times) We got pregnant with T when S was 9 months old and that suited us well. Also think about how you will breastfeed while pregnant, if you want to have them close together. I was only feeding S a few times a day by the time I fell pregnant, and even that was pretty ugh, as I felt very nauseous and the feeding seemed to make it worse. I don't know how I would have gone, had I been feeding a three- or four-month-old. But that's just me.