I am a healthy 29 year old woman who is 22 weeks pregnant with twins. I am not obese, do not smoke (never have), no family history of blood clots. I am worried about a DVT in my left calf. I have had aches and pains in my calf for the past 3-4 days.?

Need to examine. It is not feasible to provide a meaningful opinion without examining you. For the sake of your and your babies health, you should be under the care of a doctor and should discuss the matter with her/him.