Research question: Is there an association between ovarian response and perinatal outcomes? Design: A retrospective, single-centre cohort study including all women undergoing their first ovarian stimulation cycle in a gonadotrophin releasing hormone antagonist protocol, with a fresh embryo transfer that resulted in a singleton live birth from January 2009 to December 2015. Patients were categorized into four groups according to the number of oocytes retrieved: one to three (category 1), four to nine (category 2), 10–15 (category 3), or over 15 oocytes (category 4). Results: The overall number of patients analysed was 964. No relevant statistical difference was found among neonatal outcomes across the four ovarian response categories. Neonatal weight (in grams) was comparable between all groups (3222 ± 607 versus 3254 ± 537 versus 3235 ± 575 versus 3200 ± 622; P = 0.85, in categories 1, 2, 3 and 4, respectively). No statistically significant differences were found among the ovarian response categories for birth weight z-scores (taking into account neonatal sex and delivery term). The incidence of pre-term birth and low birth weight was comparable across the different ovarian response groups (P = 0.127 and P = 0.19, respectively). Finally, the occurrence of adverse obstetric outcomes did not differ among the ovarian response categories. Multivariate regression analysis revealed that the number of oocytes was not associated with neonatal birth weight. Conclusions: No association was found between ovarian response and adverse perinatal outcomes in antagonist IVF and intracytoplasmic sperm injection cycles. Future, larger scale and prospectively designed investigations are needed to validate these results.