rebecca--It really varies, I think, with each pg'cy. If you've got a chart on ff, you can browse through other charts and be selective with the criteria... i.e. You could look up charts that end with a BFP that showed an implantation dip and had low BBT's and implantaion spotting... just an example... but both my pgcy's were completely different from each other... and then my last one with my 4th m/c, was again, completely different than with my boys. The charting definitely helps, tho, I think.... sorry if that wasn't much help!