Meta‐analysis of heparin combined with aspirin versus aspirin alone for unexplained recurrent spontaneous abortion

Background Unexplained recurrent spontaneous abortion (URSA) frustrates women of childbearing age profoundly, and effective therapies are particularly important. Objective To compare the efficacy of heparin combined with aspirin and aspirin alone for URSA. Search strategy Electronic databases (PubMed, Medline, Web of Science, Clinical key and Cochrane Library) were searched for relevant studies from database inception to August 2019. Selection criteria Studies of women of childbearing age with at least two consecutive abortions were included. Data collection and analysis Relevant items were extracted, tabulated, and subjected to STATA for data analysis. Study women were divided into group A (taking heparin plus aspirin) and group B (taking aspirin alone). The primary outcome was the rate of live birth. Main results Women from eight randomized controlled trials were included: 493 in group A and 501 in group B. The number of live births was significantly higher in group A (P=0.003). The result remained the same in subgroup analysis by presence of antiphospholipid antibodies. Among women who had a live birth, gestational age at delivery tended to be older in group B (P=0.054). No differences in birthweight or intrauterine growth restriction were observed. Adverse effects were sporadically reported. Conclusion Among women with URSA, heparin combined with aspirin increased the live birth rate as compared with aspirin alone. There was a beneficial tendency of taking aspirin-only to prolong gestation week.