Bleeding in the first trimester should only concern you if it's very heavy, causes a lot of pain (especially one-sided pain) or is full of clots.
Lots of normal things cause spotting in the first trimester. The cervix becomes engorged with blood and sex can make it bleed. Sometimes just walking around too much can make it bleed. Sometimes the placenta as it forms causes a little bleeding. It's all normal. I spotted with both of my babies, my first for 4 weeks straight and my second only after sex until 14 weeks. It can be very normal. don't worry unless there are signs that it's a big problem, like I listed above.
at 6:57 PM on Mar. 24, 2011