Comparison between day-2 embryos obtained either from ICSI or resulting from short insemination IVF: influence of maternal age

Short incubation time prevents deleterious effects of cumulus cell degenera tion and excess spermatozoa in IVF embryos. We performed a short incubation (3 h) protocol in 328 IVF cycles, in order to compare the developmental po tential of regular IVF embryos with those originating from 316 cycles enter ed our intracytoplasmic sperm injection (ICSI) programme over the same peri od. Embryo transfers were performed in all patients on day 2. The mean numb er of embryos transferred was 1.92 for the ICSI group and 1.73 for the IVF group (P < 0.007). This was related only to the wishes of patients. However , the policy of the centre is to transfer a low number of embryos in young patients in order to avoid multiple pregnancies. All spare embryos were per mitted to grow to the blastocyst stage for freezing. Shortening incubation time did not decrease fertilization rates. In our overall population, no di fference was observed in the implantation rates per embryo for IVF (19%) or for ICSI(20%), An age-related decrease in embryo production was observed f or both groups of patients (P < 0.01 for ICSI and P < 0.001 for NF). The ag e-related decrease in embryo implantation was only significant for the IVF group (P < 0.03 for patients <30 and >35 years of age). A significant overa ll decrease in blastocyst formation was observed for spare embryos after IC SI versus IVF (34.2 versus 43.8%; P < 0.05). The significance of this obser vation is discussed.