Threatened Miscarriage: Evidence-Based Status and Advances in Western Medical Treatments

Threatened miscarriage is one of the most common complications during pregnancy and is characterized by complex and highly heterogeneous etiologies. In recent years, with the emergence of high-quality randomized controlled trials and updates in evidence-based guidelines, the management of threatened miscarriage has gradually shifted from empirical pregnancy preservation to risk stratification and precision intervention. This review summarizes the current evidence base and recent advances in Western medical treatment for threatened miscarriage, based on the latest clinical guidelines, randomized controlled trials, systematic reviews, and meta-analyses. Particular emphasis is placed on progesterone therapy, antithrombotic treatment, hormonal regulation during pregnancy, immunomodulatory therapy, tocolysis, and nutritional support. Current evidence indicates that vaginal micronized progesterone provides clear benefits for women with early pregnancy bleeding and a history of miscarriage. In contrast, the use of low-molecular-weight heparin (LMWH) and low-dose aspirin (LDA) should be strictly restricted to selected high-risk populations. Levothyroxine (LT4) and metformin may offer potential benefits in patients with specific endocrine abnormalities; however, evidence supporting their routine use remains limited. In addition, the long-term benefits of immunomodulatory and tocolytic therapies remain uncertain. Overall, the Western medical management of threatened miscarriage should be individualized based on underlying etiological mechanisms, clinical phenotypes, and evidence-based recommendations. Future studies integrating biomarkers and multi-omics approaches are warranted to advance precision phenotyping and personalized treatment strategies for threatened miscarriage.