Pregnancy itself is a state of hypercoagulability - meaning prone to develop clots. When ddimer is high , it will even more make the blood prone to clot and can give complications. So clexane(anticoagulant) is very essential to keep the levels low . A periodic follow up on the levels of ddimer will tell us when to stop clexane . Trust your doctor and do not stop or modify ongoing treatment without your primary physicians advise.