How long can implantation bleeding last?

How long after seeing implantation bleeding can I test for pregnancy?

• Ok so today marks my 14th day past my positive LH surge OPK. I have not got my period yet. I took a test this morning and it said no. Last month was the first month in a long time that I actually started "tracking" my ovulation with OPK again. We have been tying to get pregnant with our second child for 9 months (well March was 9months) Yesterday evening I had LIGHT spotting, and I mean only when I whipped a couple times, VERY VERY little blood. If I hadn't been looking for it, I wouldn't have seen it. Then this morning I've had some brown spotting with one time it being a little pink too. I don't know if this is a sign of implantation bleeding (I didn't have that with my first pregnancy that I remember) If it is, how long after this should I test again to see if I'm pregnant? More importantly, has anyone gotten a negative and then a positive later? I would be 4 weeks along today if you count from my expected ovulation date of April 6th (I got a LH surge on the 5th) or a little over 4 weeks if you go by my last period March 18th.

• Answer:

  If it is implantation bleeding, your hormone levels will start to rise in 2-4 days. I would wait four, just to be sure. And yes, some women only get their positive 18dpo or more. It really depends on your body and how quickly your hormones rise. Since you can ovulate as much as 48 hours after your LH surge, you might only be 12dpo, in reality. Good luck! I hope you get some good news in a few days time.