Could this be implantation bleeding?

[1Mumwhowingsit]

Hi, I had unprotected sex with my partner on 11th Jan and started very light spotting/brown discharge (sorry if tmi!) yesterday and today. My periods can be irregular and I haven’t had one for a couple of months and my periods don’t usually start off this way.

Negative pregnancy test 4 days ago, so it too late for implantation bleeding? What do you think? Thanks

x

It's highly unlikely if this is the only time you had unprotected sex. Say if you ovulated 3 days later on 14th, you'd definitely have a positive pregnancy test by now.