Yes it can be a sign of preterm labor. I was going through the same thing yesterday along with vomiting and contractions. I went in to my my office he check me and listen to baby heart beat. Only dilated 1 cm but when placed on the monitor for contractions I had 5 that were like mountains at 90 and several hills ranging at 30. But bcuz my water hadn't broke and was not at 4 cm then I was sent back home. Got another appointment on tomorrow if my little guy is not here by Monday then I will be induced on Tuesday morning baby weighs over 8lbs and I am only 5"0 tall.
I bn havin da same thing for da past two days.. I bn wondering the same thing..
Contact your on call doctor. Those are sign that should be addressed