There were no effects of OXTR genotype (rs237885) on depression levels at 6 months postpartum, but when we used a prenatal depression measure, there were significant associations between rs237885 genotype G/G, which explained a significant proportion of the variance (R2 = 0.07, LR χ2 (2, N = 154) = 11.72, p = 0.003). Here, OXTR is linked to major depressive disorder.