I had the same thing and it is hard not to stress. I really did not was a c-section and was told if it did not resolve that it would be required. Was also told bed rest may be necessary but most resolve so not to stress. They have to tell you all those scary things. At my 19 week scan my cervix was half covered. My ob had no trouble with me then going on an oversea's holiday for 3 weeks involving lots of walking etc. Although he did say no sex while away just to be on the safe side, and that was mostly as a hospital visit to check on bub if I had bleeding would have been costly. I was told the placenta would most likely move up and was booked in for a 32 week scan. Due to unrelated problems at 29 weeks they did an u/s and it showed that the placenta was now 1cm away and they expected it would continue moving up so not to worry. Then due to those unrelated problems DD had to come out via emergency c-section so never got to find out. I would not worry if I were you. As J13 says most are resolved Congratulation on your pregnancy and enjoy.