Hi @Yellowdaff25 that's an interesting chart. I don't know about using the chart to determine pregnancy/implantation, only ovulation, but when I charted previously before my last pregnancy (ended in extreme premature at 19 weeks on September :(), there was no implantation dip, and my temp absolutely plummeted the day I got my positive test. The test was a shock, I thought AF was arriving three days early.
In October, the month after our son's loss, we were actively preventing at the time, but my smart watch saved my temp data anyway, and there was a huge spike on 7DPO. I wasn't pregnant, obviously, but I remember thinking it odd to have one outlier like that, and that if I were trying it might make me excited to think it an implantation dip.
This time, I ovulated CD12/13 but Fertility Friend has put it at CD11 for some bizarre reason - I didn't even get my first positive OPK until CD12, and I have a super sharp surge and peak (peak arrived just half an hour after first positive OPK), so I don't think it's as exact as everyone believes it to be sometimes. No idea what it's doing!
Then again, I've seen charts with very clear implantation dips, temp spikes and eventual positives. It's a fun game of wait and see 😆
@ThatSnugSwan Ovulation happens 12-48 hours after your peak OPK (the darkest/highest reading compared to any others taken), so there is a window of 1-2 days post-peak. As far as I understand, the greatest chances of conceiving happen before ovulation (sperm already waiting for egg), but it doesn't hurt to DTD after peak day too, just in case the egg releases later within the window. So you have a good chance! BBT can help confirm ovulation has happened afterwards with a consistent temperature rise for 3 days running, but it's also not exact (see picture where it had incorrectly guessed ovulation happened on CD11 for me based on my next three temps).