Interesting. I just came over here to ask the very same question. At 4 months PP, my cycle returned. The 2nd one arrived 21 days later. Normally, I have 26 or 27 day cycles, very very regular. Now, I'm still waiting for the 3rd, and today marks the 30th day. I did a pregnancy test yesterday (although not in the morning, I did it in the afternoon) and it was negative. I googled for this information, and found very little, so would be interested in hearing other womens' experiences with the return of AF. How long does it take to become regular again? Is it possible to return to BF-related amenorrhea after your cycle resumes?