Low-molecular-weight heparin for prevention of preeclampsia and other placenta-mediated complications: a systematic review and meta-analysis

Preeclampsia is thought to be a total body (called “systematic”) syndrome that likely starts with poor circulation between the placenta and uterus during early/mid pregnancy. Because of this possible cause, several smaller studies have been done giving women low-molecular weight heparin (an “anticoagulation” medicine that decreases the risk of forming blood clots) during pregnancy to see if it could help prevent preeclampsia. In some studies the heparin was given alone or in a combination with low-dose aspirin. The results of these studies are conflicting; some show a large reduced risk for preeclampsia, small reduced risk, and some no reduced risk. So, researchers in this study combined all of the data from these smaller studies into one big study of 2,795 women in a meta-analysis to ask if giving low-molecular weight heparin can really decrease the chance of preeclampsia. Researchers found when they pooled all these data, women taking heparin had a 38% decreased odds of developing preeclampsia compared to women not taking heparin. The chances for preventing preeclampsia were even better if the heparin was started before 16 weeks of pregnancy (45% decreased odds of preeclampsia). Women taking heparin also had a 39% decreased odds for a small-for-gestational-age baby, and 51% decreased odds of perinatal death. If heparin was combined with low-dose aspirin, the odds of preeclampsia were lower compared to just taking aspirin alone. 

Take home message: In research studies, taking low-molecular weight heparin is associated with a substantial decreased odds of developing preeclampsia. The next step for this research would be to conduct a large randomized trial designed to specifically test the effects of heparin on preventing preeclampsia.

Link: https://reader.elsevier.com/reader/sd/pii/S0002937820312886?token=A3BDB8A887780AE0DCBCF625BCB7B749B09E5A2987563E5139EA0C26BAE824D6ACBC981E7EB106DC4CF6B2765291F578&originRegion=us-east-1&originCreation=20211216113841 

About Research Roundup

Each quarter, our team of researchers reviews the most current studies related to hypertensive disorders of pregnancy and selects those studies they feel will be of greatest interest to our community to summarize.

Special thanks to our volunteer research team, who under the leadership of Dr. Elizabeth Sutton, make Research Roundup possible: Alisse Hauspurg, MD Felicia LeMoine, MD Jenny Sones, PhD, DVM, and Robin Trupp, PhD, RN.