Found this on another site. Implantation happens as early as 3 dpo.

[TTC5]

This link was posted by a medical student???
Endotext.com - Female Reproductive Endocrinology - Premenstrual Syndrome

[love being a mummy]

Haven't read the entire article yet but I thought BFP start showing once implantation happens wouldn't we start getting BFP's by 5dpo or 6dpo

[TTC5]

It says in there further down about the HCG levels entering maternal system will try and copy it here. I have heard some people claim they have had a BFP as early as 6 days but never believed it lol

[rainbowflower]

had a quick read and couldn't see where it says that it happens as early as 3dpo?

[TTC5]

Off to work soon but will take some screen shots

[TTC5]

MM I think this student wasnt reading it properly (as did I when I read it briefly!) She swears she is right now and claims her professor said so too but mmmmm I am not sure. It does say, though that it can take as little as 3 days for it to travel down to the uterus?? I thought it took around 5/6 days (same time implantation happened?)

[love being a mummy]

I read some info that says it takes 7-10dpo for it travel down the tube and then once in the uterus it implants.

[nuthinbutpink]

I can tell you from doing IVF that the vast majority of embryos do not hatch until 5 days at the very earliest and usually say 6 after ovulation, which is egg retrieval day for us. It cannot implant and make HCG until it hatches from its shell. The earliest we ever see a BFP after transfer, 5 days after O, is 4 days later and that is usually only a twin pregnancy- 9 days past ovulation is the equivalent. many get BFPs 10 days past O. Not possible at even 6 days past at all on a stick. Blood test could show a BFP earlier.

[hmskl4]

Gotta agree w/ NBP, I've transferred several times using 3 day embabies and none of them where hatching, or even close to hatching, shoot they all were only 8 cells, 10 the most (morula's). I've transferred some 5 day embabies and none of them where hatching, but you can do a google search and see some 5 day (some 6 or 7 day embabies) hatching (hatching is where they break out of the 'shell' to attached to the uterus).

I don't believe it, but again, there is so much we don't understand about ourselves .