So non-pregnant ladies can have an HCG level between 0-5 at the one of implantation, which could explain why some can get super early BFPs and others not until after AF.

Below is a picture from the “simulator” that whenmybaby website has.

So, for example, if I implanted at 7dpo with a base HCG of 1, and it doubles every 48-72 hours, I wouldn’t get a positive on an FRER (sensitivity being 6.5, I think) until 13 or 14dpo! And if my HCG was 0 at implantation? No BFP until even LATER!

So, for all of us worrying about BFNs before AF, just know its not too late!! Take a breath and trust in your body. And if this ends up not being your month, try try and try again!!