Objective::Clinically, low-dose aspirin and progesterone are frequently used to prevent pregnancy loss. We investigated the effect of these drugs on the biological behavior of human extravillous trophoblasts n in vitro.n Methods::HTR-8/SVneo cells were cultured n in vitro and treated with different concentrations of aspirin and progesterone. The proliferation, invasion, and apoptosis of HTR-8/SVneo cells were assessed using a cell counting Kit-8 assay, Matrigel Transwell assay, and Hoechst staining, respectively. Reverse transcriptase polymerase chain reaction was used to verify the expression of related genes. Reactive oxygen species (ROS) levels were detected using the 2,7-dichlorofluorescin diacetate assay.n Results::Low-dose aspirin alone, progesterone alone, or aspirin plus progesterone upregulated the proliferation and invasion and decreased the apoptosis of HTR-8/SVneo cells. Moreover, the expression of marker of proliferation Ki-67 (n MKI67), matrix metalloproteinases 2 (n MMP2), and n MMP9 was increased. In addition, low-dose aspirin plus progesterone exerted stronger anti-apoptosis effects than low-dose aspirin and progesterone alone. Interestingly, aspirin upregulated the expression of progesterone receptor (n PGR). Treatment with hydrogen peroxide (Hn 2On 2) promoted ROS production in HTR-8/SVneo cells; however, low-dose aspirin plus progesterone significantly restricted Hn 2On 2-mediated ROS production and apoptosis in HTR-8/SVneo cells.n Conclusions::These data suggest that low-dose aspirin and progesterone promote proliferation and invasion and cooperatively reduce oxidative stress and apoptosis in trophoblasts n in vitro. These results may provide an experimental basis for the combined application of aspirin and progesterone to prevent unexplained recurrent spontaneous miscarriage, especially in patients with trophoblast dysfunction.n “,”Objective::Clinically, low-dose aspirin and progesterone are frequently used to prevent pregnancy loss. We investigated the effect of these drugs on the biological behavior of human extravillous trophoblasts n in vitro.n Methods::HTR-8/SVneo cells were cultured n in vitro and treated with different concentrations of aspirin and progesterone. The proliferation, invasion, and apoptosis of HTR-8/SVneo cells were assessed using a cell counting Kit-8 assay, Matrigel Transwell assay, and Hoechst staining, respectively. Reverse transcriptase polymerase chain reaction was used to verify the expression of related genes. Reactive oxygen species (ROS) levels were detected using the 2,7-dichlorofluorescin diacetate assay.n Results::Low-dose aspirin alone, progesterone alone, or aspirin plus progesterone upregulated the proliferation and invasion and decreased the apoptosis of HTR-8/SVneo cells. Moreover, the expression of marker of proliferation Ki-67 (n MKI67), matrix metalloproteinases 2 (n MMP2), and n MMP9 was increased. In addition, low-dose aspirin plus progesterone exerted stronger anti-apoptosis effects than low-dose aspirin and progesterone alone. Interestingly, aspirin upregulated the expression of progesterone receptor (n PGR). Treatment with hydrogen peroxide (Hn 2On 2) promoted ROS production in HTR-8/SVneo cells; however, low-dose aspirin plus progesterone significantly restricted Hn 2On 2-mediated ROS production and apoptosis in HTR-8/SVneo cells.n Conclusions::These data suggest that low-dose aspirin and progesterone promote proliferation and invasion and cooperatively reduce oxidative stress and apoptosis in trophoblasts n in vitro. These results may provide an experimental basis for the combined application of aspirin and progesterone to prevent unexplained recurrent spontaneous miscarriage, especially in patients with trophoblast dysfunction.n