KISS1 and spontaneous abortion: Patients with kisspeptin levels less than 1630 pmol/L had a 13.8% chance of miscarriage being subsequently diagnosed (ie, 13.8% positive predictive value), whereas patients with kisspeptin levels greater than 1630 pmol/L had a 1.0% chance of miscarriage being subsequently diagnosed (ie, 99.0% negative predictive value).