I agree with the ladies who posted above I don't think it's much to worry about. Most likely it's caused from the strain of coughing. If you are overly concerned please call your ob and they can check things out.
I agree, not likely anything to worry about. It could easily be from the strain of so much coughing. It's possible that you just have a sensitive cervix and it gets irritated easily. As long as it doesn't become bright red or become full on bleeding or you start cramping, I wouldn't worry. If you are ever in doubt, there's no harm in calling your OB and taking it easy for a few days.
No I don't think it's anything to worry about.
When I was pregnant 6 years ago, I had the same thing. Spotting around 10 weeks pregnant. That's when they did my first ultrasound. Everything was good. I went on to deliver a healthy baby boy who's now 6.
If you are still worried, talk to your OB. But it's common to have random spotting during pregnancy.