Comment: The quality of evidence is downgraded by study limitations (no blinding, incomplete outcome data), by imprecise results (few patients and outcome events), and by inconsistency (unexplained variability in results).
A Cochrane review included 3 studies with a total of 386 subjects. Peri-implantation low molecular weight heparin (LMWH) administration during assisted reproduction was associated with a significant improvement in live birth rate compared with placebo or no LMWH (odds ratio (OR) 1.77, 95% CI 1.07 to 2.90; 3 trials, n=386 women, I² = 51%, very low quality evidence with high heterogeneity). There was also a significant improvement in the clinical pregnancy rate with use of LMWH (OR 1.61, 95% CI 1.03 to 2.53; 3 trials, n=386, I² = 29%, very low quality evidence with low heterogeneity). However, these findings should be interpreted with extreme caution as they were dependent upon the choice of statistical method: they were no longer statistically significant when a random-effects model was used. Adverse events were poorly reported in all included studies. However, LMWH did cause adverse effects including bruising, ecchymosis, bleeding, thrombocytopenia and allergic reactions.
Date of latest search: 6 May 2013