15 weeks pregnant. awful pain in both upper thighs and knees when i walk. had u/s done to rule out blood clots and came back good. any ideas?

Leg pain: Hi grc123, your symptoms sound suspicious for sciatica in pregnancy. As you can imagine tremendous stress is put on the lower back during pregnancy, especially L4-L5, where the sciatic nerve originates. Low heeled shoes, arch supports, firm bed, physio, heat and cold packs, and sleeping on your side with a pillow between your legs can be helpful. Sometimes a long walk can be helpful.