Objective: To evaluate the effect of bed rest following embryotransfer (ET) on the results of an in vitro fertilization (IVF) program. Design: A prospective randomized study. Setting: Gyn.-Obst. Department - Assisted Reproduction Centre, 1st Medical Faculty of Charles University Prague and General Hospital, Prague. Methods: After randomisation of patients on two groups (N - no bed rest, L - bed rest), embryo transfer (ET) was performed and all patients stand-up 20 minutes later. Group N went home, group L continued bed rest in the hospital overnight. We compared results of IVF in both groups. Results: Both groups (N = 20 patients, L = 18 patients) were comparable in the age, number of previous IVF attempts, stimulation protocol, person performing ET, number of transferred embryos, percentage of ICSI, percentage of diagnosis „tubal infertility“ and age of embryos in the day of ET. Results for group N (no bed rest) were in all parameters better than for group L: implantation rate (IR) (22.5% versus 14.5%), IR of high quality embryos (25.8% versus 16.7%), pregnancy rate (50% versus 22.2%, p = 0,08), Take-home baby rate (40% versus 11%, p = 0,07). No of results reached clear statistical significance as the study was finished for ethical reasons (worse results of more difficult therapy in group L). Conclusion: The overnight bed rest in the hospital following ET did not ameliorate results of IVF. There is a strong tendency to negative effect of bed rest. Similar results may be found on other authors, but they did not extend the sense of their studies to the question of negative effects of the bed rest after ET, being satisfied with the result of „no worse results after no bed rest“.

        Key words: embryo transfer, bed rest, IVF results, implantation rate, pregnancy rate