Implantation bleeding is usually very light and occurs around 2-4 days before expected period is due. So you could usually get a positive pregnancy test when you discover the spotting. If it's negative, wait a couple days then retest.
As far as pullout method: I've read that it's more effective if he hasn't ejaculated within 24 hrs, or 48 hrs to be safer. That's how the sperm can be in pre-ejaculatory fluids. This means any ejaculation, from sex, masterbation or wet dreams. If it's been less than 25-48 hrs you increase the chances of sperm being in the pre-fluids. Also, some men don't withdrawl fast enough. Even if they intend to they might not get enough notice to pullout. It's very risky. My husband and I have used that method for years. I conceive very easily when trying. So it has worked for us. Mainly because we know to not use that method less than 24-48 hrs after ejaculation. Though, if pregnancy happened it would have been fine. So the risk factor wasn't so servere. If we were greatly avoiding pregnancy under no circumstances would we use the pullout method. Spermicide works well for days we don't do pullout method.
Good luck!
Hi!
I ALWAYS recommend a pregnancy test, because anything is possible. In your case, I doubt that you are pregnant, it is more likely that you are just having an unusual cycle -- these are common, and usually nothing to worry about. In the future, if you are really not ready for a baby, Plan B (emergency contraception) can help to provide some peace of mind.
Hope this helps!
Dr B