Dysfunctional mitochondrial biogenesis and abnormal ultrastructure of mitochondria in first-trimester villi from polycystic ovary syndrome (PCOS) patients with euploid miscarriage. A and B, The level of mitochondrial DNA (mtDNA) CN (ND1) and mtDNA CN (COX3) were measured by real-time quantitative polymerase chain reaction to assess mitochondrial biogenesis in first-trimester villi from PCOS patients with euploid miscarriage group (n = 7) and the control group (n = 7). C, The ultrastructure of mitochondria in villi of the PCOS group and control group were observed using the transmission electron microscopy assay. The arrow indicates mitochondria. Scale bar: 500 nm. *P less than .05; **P less than .01; ***P less than .001.