I’m skeptical that they exist to be honest. I’m currently 13dpo, af due tomorrow. I know I definitely ovulated this month (confirmed by blood tests) and I assume it was two weeks ago tomorrow as I was having ewcm and positive opks the Wednesday and Thursday and although I got a positive opk on the Friday, it quickly turned negative when I took another a few hours later.
Anyway, a few days ago I started having mild af type cramps which were kind of on and off for about a day but then they disappeared and I’ve not had them since. I usually get sore boobs a week before af but this cycle they’ve been completely fine, not even slightly tender so I’m guessing that means I’m out (along with two very negative frer’s taken yesterday and today!) but I just wondered what the cramps might have been (they weren’t gas pains lol) but like I said, I don’t actually believe implantation cramps are a real thing.