Had a thrombophlebitis last year supposedly caused by airplane travel. I'm active and have literally no other risk factor, not even family history. My ob-gyn said I dont need a preventive blood thinning treatment since it happened only once. The thing is I flip out each time I get back from a run and my left calf feels sore, which was the first symptom I felt before it turned blue and had to rush to the ER. Anyone else had a thrombophlebitis pre-pregnancy and turned out OK without blood thinners? Please share!