Chinese herbal medicine for the treatment of recurrent miscarriage: a systematic review of randomized clinical trials

Background: Traditional Chinese medicine has been widely used for the treatment of recurrent miscarriage in China and other Asian countries for long time. We conducted this review to systematically summarize the evidences of Chinese herbal medicine (CHM) for the prevention and treatment of recurrent miscarriage in randomized trials, and evaluate the effectiveness and safety of CHM compared with placebo or conventional medicine. Methods: We searched studies in PubMed, ClinicalTrials, the Cochrane Library, CNKI, SinoMed and VIP databases until December, 2012. Randomized trials on CHM alone or in combination with conventional medicine for recurrent miscarriage compared with placebo or conventional medicine were included. We evaluated the methodological quality of each included trials using the Cochrane risk of bias tool. Results: A total of 41 RCTs (3660 participants) were included. The majority of trials had a high or unclear risk of bias. CHM used alone or plus progesterone-based treatment showed superior effect over progesterone-based treatment in improving live birth rate and embryonic developmental state (measured by B ultrasound). However, there is substantial heterogeneity within each subgroup analysis (I-2 ranging from 35% to 71%). CHM plus progesterone and hCG-based treatment was superior to progesterone and hCG-based treatment in improving the embryonic developmental state, but not live birth rate. No severe adverse events were reported in relation to CHM. Conclusions: Some Chinese herbal medicines or in combination with progesterone-based treatment demonstrated potentially beneficial effect in improving live birth rate and embryonic developmental state for women with recurrent miscarriage. However, due to the substantial heterogeneity among the herbal interventions and limitations of methodological quality of the included trials, it is not possible to recommend any specific CHMs for recurrent miscarriage. Further rigorous clinical trials are warranted to evaluate the efficacy and safety of CHM.