目的　探讨早期自然流产妇女血清一氧化氮 (NO)含量变化与自然流产的关系。方法　应用酶法分别测定并比较正常妇女、早孕妇女、早期自然流产妇女静脉血中NO的含量。结果　早孕妇女血清NO水平较正常妇女血清NO升高 (P <0 .0 1) ,自然流产妇女NO水平明显高于早孕妇女 (P <0 .0 1)。结论　妊娠早期NO水平异常升高 ,可产生细胞毒作用 ,导致自然流产发生。应用NO抑制剂可避免自然流产 ;反之 ,如使用NO供体则有助于终止妊娠。 Objective To investigate the relationship between changes of serum nitric oxide (NO) and spontaneous abortion in spontaneous abortion women. Methods The levels of NO in venous blood of normal women, early pregnant women and early spontaneous abortion women were measured and compared respectively by enzyme method. Results Compared with normal women, the level of NO in serum of pregnant women was higher than that of normal women (P <0.01). The level of NO in spontaneous abortion women was significantly higher than that in pregnant women (P <0.01). Conclusions The abnormal increase of NO level in early pregnancy may result in cytotoxicity, leading to spontaneous abortion. NO inhibitors are used to avoid spontaneous abortion; conversely, using NO donors can help terminate the pregnancy.