Lots of women do spot during pregnancy. Is it brownish in color? That's old blood and nothing to worry about. If it is pink or red, the cervix is very vascular during pregnancy and can get irritated and you'll have blood. These are common things during pregnancy. If it increases or you start having heavy/bright red bleeding obviously call your doctor. But you are out of the true danger zone of miscarriage during pregnancy once you passed 13 weeks so the odds really are that this is nothing. good luck