Research questionWhat is the effect of adenomyosis types on IVF and embryo transfer (IVF-ET) after ultra-long gonadotrophin-releasing hormone (GnRH) agonist protocol? DesignPatients who underwent the first cycle of IVF-ET with ultra-long GnRH agonist protocol were included in this retrospective cohort study. They were divided into three groups: (A) 428 patients with diffuse adenomyosis; (B) 718 patients with focal adenomyosis; and (C) 519 patients with tubal infertility. Reproduction outcomes were analysed. ResultsLogistic regression analysis revealed that, compared with focal adenomyosis and tubal infertility, diffuse adenomyosis was negatively associated with clinical pregnancy and live birth (clinical pregnancy: A versus B: OR 0.708, 95% CI 0.539 to 0.931, P = 0.013; A versus C: OR 0.663, 95% CI 0.489 to 0.899, P = 0.008; live birth: A versus B: OR 0.530, 95% CI 0.385 to 0.730, P < 0.001; A versus C: OR 0.441, 95% CI 0.313 to 0.623, P < 0.001), but positively associated with miscarriage (A versus B: OR 1.727, 95% CI 1.056 to 2.825, P = 0.029; A versus C: OR 2.549, 95% CI 1.278 to 5.082, P = 0.008). Compared with patients with tubal infertility, focal adenomyosis was also a risk factor for miscarriage (B versus C: OR 1.825, 95% CI 1.112 to 2.995, P = 0.017). ConclusionsCompared with patients with focal adenomyosis or tubal infertility, the reproduction outcomes of IVF-ET in patients with diffuse adenomyosis seems to be worse.