The association between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the first half of pregnancy and pregnancy loss is still unknown. Infections by other coronaviruses, such as severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV), appear to increase the risk of miscarriage. The purpose of this study is to assess whether SARS-CoV-2 infection increases the risk of miscarriage. Firstly, a narrative review of the literature on animal and human studies was performed to analyze the immunopathological mechanisms of SARS-CoV-2 infection during preconception and early pregnancy, by which it may increase the risk of miscarriage. Secondly, a systematic review/meta-analysis of studies was conducted to assess the prevalence of miscarriage in COVID-19 patients diagnosed during pregnancy. Meta-analysis of proportions was used to combine data, and pooled proportions were reported. Seventeen case series and observational studies and 10 prevalence meta-analyses were selected for the review. The estimate of the overall miscarriage rate in pregnant women with COVID-19 was 15.3 % (95 % CI 10.94–20.59) and 23.1 (95 % CI 13.17–34.95) using fixed and random effect models, respectively. Based on the data in the current literature, the miscarriage rate (<22 weeks gestation) in women with SARS-CoV-2 infection is in the range of normal population. Well-designed studies are urgently needed to determine whether SARS-CoV-2 infection increases the risk of miscarriage during periconception and early pregnancy.

妊娠前半段严重急性呼吸系统综合症冠状病毒 2 (SARS-CoV-2) 感染与流产之间的关联仍未知。其他冠状病毒感染，如严重急性呼吸系统综合症冠状病毒 (SARS-CoV) 和中东呼吸系统综合症冠状病毒 (MERS-CoV)，似乎会增加流产的风险。本研究的目的是评估 SARS-CoV-2 感染是否会增加流产风险。首先，对动物和人类研究文献进行叙述性回顾，分析 SARS-CoV-2 在孕前和早孕期间感染的免疫病理机制，这可能会增加流产风险。第二，对研究进行了系统回顾/荟萃分析，以评估在怀孕期间诊断出的 COVID-19 患者的流产率。比例的荟萃分析用于合并数据，并报告了汇总比例。选择了 17 个病例系列和观察性研究以及 10 个患病率荟萃分析进行审查。使用固定效应模型和随机效应模型，COVID-19 孕妇的总体流产率估计值分别为 15.3%（95% CI 10.94-20.59）和 23.1（95% CI 13.17-34.95）。根据目前文献中的数据，感染 SARS-CoV-2 的女性的流产率（<妊娠 22 周）处于正常人群范围内。