TY - JOUR UR - https://archiv.ub.uni-heidelberg.de/volltextserver/22936/ A1 - Holschbach, Verena A1 - Weigert, Julia A1 - Dietrich, Jens Erik A1 - Rösner, Sabine A1 - Montag, Markus A1 - Strowitzki, Thomas A1 - Toth, Bettina CY - London IS - 37 PB - BioMed Central EP - 8 N2 - Background: The aim of this study was to compare pregnancy rates in patients undergoing IVF/ICSI with embryo transfer after 4 and 5 days of culture in a closed incubation system with integrated time-lapse imaging. Methods: Out of n?=?2207 in vitro fertilization (IVF)/ intracytoplasmic sperm injection (ICSI) cycles performed between January 2011 and April 2016 at a tertiary referral university hospital, a total of n?=?599 IVF/ICSI cycles with prolonged embryo culture in an integrated time-lapse system (EmbryoScope© (Vitrolife)) until day 4 or 5 were retrospectively analyzed with regard to embryo morphology and pregnancy rates. Results: A transfer on day 5 compared to a transfer on day 4 did not result in higher implantation and clinical pregnancy rates (IR 29.4% on day 4 versus 33.0% on day 5, p?=?0.310; CPR 45.2% on day 4 versus 45.7% on day 5, p?=?1.0). The percentage of ideal embryos transferred on day 4 was comparable to the rate of ideal embryos transferred on day 5 (41.6% versus 44.1%, p?=?0.508). However, on day 4 a significantly higher number of embryos was transferred (1.92 on day 4 versus 1.84 on day 5, p?=?0.023), which did not result in higher rates of multiple pregnancies. Conclusions: Pregnancy rates in IVF/ICSI cycles with integrated time-lapse incubation and transfer on day 4 and 5 are comparable. This finding provides the clinician, IVF laboratory and patient with more flexibility. Trial registration: This study was retrospectively registered by the local ethics committee of the University of Heidelberg on December 19, 2016 (registration number S-649/2016). SP - 1 JF - Reproductive Biology and Endocrinology ID - heidok22936 VL - 15 AV - public SN - 1477-7827 Y1 - 2017/// TI - Pregnancy rates of day 4 and day 5 embryos after culture in an integrated time-lapse incubator ER -