LDA and LMWH vs LDA Alone in High-risk Patients for Preeclampsia Prevention

This study tests whether adding a blood-thinning injection (low molecular weight heparin, LMWH) to low-dose aspirin works better than aspirin alone at preventing preeclampsia (dangerously high blood pressure during pregnancy) in women identified as high-risk. **You may be eligible if...** - You are pregnant with one baby (singleton pregnancy) - You are less than 16 weeks pregnant - You are at high risk for preeclampsia based on a first-trimester screening test (risk greater than 1 in 150) - You are 18 or older and can be reached by phone for follow-up **You may NOT be eligible if...** - You are carrying more than one baby - You are already taking aspirin long-term for another condition - Your baby has a serious detected birth defect - You have a known allergy to aspirin or heparin - You have a bleeding disorder, active peptic ulcer, severe low platelets, or a history of heparin-induced blood problems - You have severe kidney failure - You live in a remote area without phone access Talk to your doctor to see if this trial is right for you.