Abstract Study question To evaluate the effectiveness of three recombinant gonadotropins against the human menopausal gonadotropin currently in use at the fertility clinic. Summary answer Human menopausal gonadotropin and Follitropin Delta had the highest pregnancy and live birth outcomes compared to Follitropin Alpha 1 and 2. What is known already Currently there is no robust evidence showing a difference in pregnancy and live birth outcomes between urinary (uFSH) and recombinant (rFSH) gonadotropins. However, there is some evidence indicating that uFSH slightly increases pregnancy outcomes in advanced maternal age (AMA). The aim of this study was to evaluate the pregnancy and live birth outcomes in two age groups (<38 years old and ≥38 years old) for three newly introduced rFSH (Follitropin Delta [FD], Follitropin Alpha 1 [FA1], Follitropin Alpha 2 [FA2]) against a human menopausal gonadotropin (hMG). Study design, size, duration Patients were randomly allocated to each gonadotropin; hMG, FD, FA1 and FA2. The following outcomes were analysed; positive test rate (PTR) (no. positive test/no. oocyte collections), clinical pregnancy rate (CPR) (no. fetal hearts/no. oocyte collections), biochemical rate (BR) (no. no clinical pregnancies/no. positive tests), implantation rate (IR) (no. sacs seen/no. embryos transferred) and live birth rate (LBR) (no. live births/no. oocyte collection) for two age groups; <38 years old (<38) and ≥38 years old (AMA). Participants/materials, setting, methods The study included 1352 patients between July 2018 and December 2019. The <38 group had 1011 patients; hMG (348), FD (38), FA1 (244), FA2 (381). The AMA group had 341 patients; hMG (141), FD (12), FA1 (87), FA2 (101). Chi-square and Kruskal-Wallis tests were used for statistical analysis and p-values of < 0.05 were considered statistically significant. Main results and the role of chance In the <38 group, hMG and FD had a significantly higher PTR compared to FA1 (32.6%, 43.6%, 22.1% respectively) (p = 0.009, p = 0.004), as well as a significantly higher CPR (26.9%, 35.9%, 17.5% respectively) (p = 0.012, p = 0.008) and LBR (21.9%, 33.3%, 13.4% respectively) (p = 0.013, p = 0.0019). Patients stimulated with FD also had a significantly higher LBR compared to FA2 (33.3%, 19.5%) (p = 0.043). No significant differences were seen in the PTR (31%) or CPR (25.1%) when FA2 was compared to hMG and FD. No significant differences were seen between the 4 gonadotropins (hMG, FD, FA1 and FA2) for IR (36.8%, 46.9%, 27.9%, 38.5% respectively) (p = 0.14) and BR (17.3%, 17.6%, 21.3%, 19% respectively) (p = 0.95) In the AMA group, hMG, FD and FA1 had a significantly higher CPR compared to FA2 (20.5%, 30%, 20%, 9.3% respectively) (p = 0.021, p = 0.048, p = 0.041). Patients stimulated with FA1 had a significantly higher PTR compared to FA2 (26.3%, 14.4% respectively) (p = 0.049). No significant differences were seen compared to hMG and FD (25%, 30% respectively) (p = 0.0504, p = 0.19). No significant differences were seen between the 4 gonadotropins (hMG, FD, FA1 and FA2) for IR (23.7%, 35.7%, 21.8%, 12.5% respectively) (p = 0.094), BR (18.2%, 0%, 23.8%, 33.3% respectively) (p = 0.51) and LBR (15.2%, 20%, 12.5%, 9.3% respectively) (p = 0.53). Limitations, reasons for caution One limitation was that the FD group was the smallest study group; hence further patients should be included to obtain more reliable results. Another limitation was that statistical analysis was not performed using outcomes per cycles started, being unable to know how many abandoned cycles there were for each gonadotropin. Wider implications of the findings: hMG and FD have had the highest pregnancy and live birth outcomes for both the <38 and AMA groups and the clinic will continue to use both gonadotropins. Parameters such as staff and patient feedback, cost implications and cost-effectiveness per live birth rate now need to be considered. Trial registration number NA