Do labor pains start in the top of the groin and move down toward the knee cap?

No.: What you describe could be a neural entrapment syndrome of the nerves (ilioingional or iliofemoral) tha pass near your groin. Labor pains are typically midline colics that can be felt in the lower abdomen, mid-abdomen and/or loer back. They come and go every 2-5 minutes and are increasingly painful as the cervix dilates and the fetal head descends in your pelvis. Epidural can relieve them quickly.