Norethisterone - question

[FromGirders]

Not sure if I've spelt it right, but can't be bothered getting the packet out to check!
I'm wanting to delay my period a bit, and have been prescribed norethisterone. It says to start taking it three days before my period is due - however, I usually have a couple of days spotting before i start "properly" iyswim. Do I start taking it three days befre the spotting is expected, or three days before serious bleeding occurs? I'm not hugely regular, so it will be a wee bit of a guessing game anyway.
TIA.

Three days before proper bleeding (ie enough for you to have to put a pad on).

Thank you!

Now, I'm just checking. Do you actually know this, or are you guessing because you're knocking off unanswered threads?

I know this because I had to have meds in the same circumstances and asked my GP the same question.

Cynic

Ta!!
I forgot to ask my GP