This study analysed the relationship between serum progesterone/oestradiol concentrations and IVF pregnancy outcomes in gonadotrophin-releasing hormone agonist protocols. A total of 2921 infertile women undergoing IVF were assigned to four groups according to serum progesterone and oestradiol concentrations on the day of human chorionic gonadotrophin (HCG) administration: group 1 (control) progesterone < 3.34 nmol/l and oestradiol < 19,124 pmol/l; group 2 (high oestradiol); group 3 (high progesterone); group 4 (high progesterone and high oestradiol). Compared with group 1, group 4 had lower clinical pregnancy and live birth rates as well as the highest ectopic pregnancy rate (29.15% versus 45.91%; 18.67% versus 34.34%; 18.10% versus 5.82%; P < 0.05). Group 3 had lower clinical pregnancy and live birth rates per embryo-transfer cycle (29.78% versus 45.91%; 20.28% versus 34.34%, respectively; P < 0.05). Clinical pregnancy rates were similar in frozen-thawed embryo transfers (FET) among the four groups. In conclusion, elevated progesterone was detrimental to live birth rates. High serum oestradiol concentration on HCG day did not affect the IVF pregnancy outcome. In combination with the elevated progesterone, high oestradiol concentrations had a potential negative effect. For these patients, FET should be suggested to improve the pregnancy outcomes. (C) 2012, Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.