Threatened abortion is a pre-abortion state with vaginal bleeding and uterine cramping in a pregnancy before 20 weeks of gestation. According to Traditional Chinese Medicine, the clinical manifestations can be classified into the categories of “excessive fetal movement” and “fetal leakage”. Fetal leakage refers to a small amount of vaginal bleeding during pregnancy that comes and stops, or drips continuously. If backache, abdominal pain or lower abdominal distension is present, accompanied by a small amount of vaginal bleeding during pregnancy, it can be concluded as excessive fetal movement.

Through literature review, the common syndrome types of clinical threatened abortion include spleen and kidney deficiency type, kidney deficiency type, blood heat type, and qi and blood deficiency type. Nourishing the kidney and strengthening the spleen, clearing heat and cooling blood, replenishing qi and nourishing blood to prevent miscarriage is the main treatment methodology in the treatment of threatened abortion. The most frequently used herbs are tonics, rheumatism-removing drugs, heat-clearing and hemostatic herbs. The drug pattern study found that Cuscuta chinensis (菟丝子), Dipsacus asper (续断)，Taxillus chinensis (桑寄生)，donkey-hide gelatin (阿胶)，Rehmannia glutinosa(熟地黄)，Angelica sinensis (当归),Ligusticum striatum (川芎)，Astragalus propinquus(黄芪)，Atractylodes macrocephala (白术)，Boehmeria nivea (苎麻根)，Eucommia ulmoides (杜仲)，Lycium barbarum (枸杞子)，Dioscorea polystachya (山药)，Codonopsis pilosula (党参) were most frequently used in the treatment of threatened abortion.

From the randomized clinical trial studies reviewed, the results uniformly show that Chinese medicine alone or in combination with Western medicine can improve the symptoms of threatened abortion. Meta-analysis showed that the intervention failure rate of the traditional Chinese medicine combination group was significantly lower than that of the western medicine control group.

As the treatment time of traditional Chinese medicine in the randomized clinical trials is short, whether short-time treatment can significantly improve observation indicators or affect pregnancy outcomes still needs further exploration. Most studies do not have long term efficacy outcomes such as the pregnancy outcome and postpartum fetal conditions, hence it could not conclude the long-term efficacy and safety of TCM herbs. The treatment time of Traditional Chinese Medicine in the study was different, the specifications of western medicine used in the control group were inconsistent, and the quality of the research paper was poor. There are publication bias, reporting bias and methodology differences such as wide variation in design, intervention and outcome measures, and problems with data calculations, which could affect the reliability of the conclusion. Higher-quality studies with larger samples are needed to conclude efficacy. Randomized clinical studies and meta-analyses have found no obvious toxicity and adverse reactions of traditional Chinese medicines or combinations of medicines, which suggests the safety of the use of traditional Chinese medicines. However, most of the literature did not report the short-term and long-term adverse reactions and safety, therefore high-quality research with larger samples are required to prove the safety usage of TCM and western medicine. It is also to note that because of the difficulty in carrying out unified clinical intervention for pregnant women in clinical studies, which limits the observation of clinical efficacy and the cumulative analysis of data.

References

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