UNiTY In 'UNiTY' UNiTYNews and UpdatesRecruitment and participating centresTrial documentationPrivacyContact us A randomised controlled trial evaluating the clinical and cost effectiveness of Intra Utertine Insemination versus In-Vitro Fertilisation for UNexplained infertiliTY. This page is for fertility professionals. For more information for patients and couples please see Spermeggembryo | Future Generations UNiTY is now open for recruitment, please get in contact with the UNiTY Trial Study Office if you have any enquiries. Many thanks to all sites and participants for your continued support. Sponsored by University of Birmingham Tweets by @UNITY_IUI_Trial Birmingham Clinical Trials Unit will be closed from 5pm Monday 22nd December 2025 and will reopen Friday 2nd January 2026. The UNiTY Trial website and data collections system will remain active during this time for routine data entry and trial randomisations. Serious Adverse Events should be reported as normal during this time. If you need to contact someone in an emergency please contact Katie Kirkham on k.l.kirkham@bham.ac.uk or 07974 715467. The UNiTY Trial Team wish you a very Merry Chirstmas and Happy New Year! Aim To evaluate the clinical and cost effectiveness of up to three cycles of Intra Uterine Insemination (IUI), compared to one cycle of In-Vitro Fertilisation (IVF) in couples with unexplained infertility. Trial Design Parallel, open, multicentre, non-inferiority, randomised controlled trial with integrated economic, healthcare science and bioethics evaluations, including an internal pilot with embedded Qualitative Process Evaluation. Participant population and sample size Couples with a diagnosis of unexplained infertility. The trial will recruit 942 couples in total, 471 per group at a 1:1 randomisation ratio. Setting Human Fertilisation and Embryology Authority (HFEA) licenced fertility treatment centres in the UK. Arms Intervention: Three cycles of letrozole stimulated Intra Uterine Insemination (IUI). Control: One cycle of In-Vitro Fertilisation (IVF) with standard ovarian stimulation and first fresh or frozen embryo transfer. Outcomes The primary outcome is live birth ≥34 weeks gestation conceived within 270 days (approximately 9 months) of randomisation, assessed at 19 months post-randomisation.