Receiver-operator characteristic (ROC) curve analysis suggested that kisspeptin had a higher diagnostic performance with respect to miscarriage when compared with hCG (ROC area under curve: 0.899 ± 0.025, kisspeptin; 0.775 ± 0.040, hCG, P < .01 vs kisspeptin) (Figure 2, C and D). This evidence concerns the gene KISS1 and spontaneous abortion.