Kisspeptin increased to a significantly lesser extent with gestational age in the cohort of women who experienced miscarriage when compared with the cohort of women with uncomplicated pregnancy [slope coefficient for increase in plasma kisspeptin (picomoles per liter per week): 305 ± 15, singleton without miscarriage; 94 ± 30, singleton with miscarriage; F = 25.2, DFn = 1, DFd = 945, P < .0001] (data not shown). Here, KISS1 is linked to spontaneous abortion.