A prospective randomised study of the optimal time for the administration of human chorionic gonadotropin (HCG) in women undergoing IVF in a gonadotropin releasing hormone (GnRH) antagonist cycle

INTERVENTION: Laboratory study; Case‐note review; Randomised controlled trial, Random allocation to receive HCG injection at: 1. Standard time delay 2. 24 h delay 3. 48 h delay CONDITION: Pregnancy and Childbirth: In vitro fertilisation (IVF) ; Pregnancy and Childbirth ; Procreative management PRIMARY OUTCOME: The main objective is to determine whether there is an optimal time to give HCG injection, and also to observe any differences in the number of eggs being collected, fertilisation rates, embryos quality and pregnancy rates among the three groups. SECONDARY OUTCOME: Not provided at time of registration INCLUSION CRITERIA: 1. Patients undergoing their first or second cycle of IVF or IVF/intracytoplasmic sperm injection (ICSI). 2. Age of partner 19‐36 years. 3. Body mass index 20‐30 kg/m2. 4. Serum follicle‐stimulating hormone (FSH) concentration in normal range.