Oocytes with smooth endoplasmic reticulum clusters originate blastocysts with impaired implantation potential

Careful oocyte observation for the presence of a smooth endoplasmic reticulum cluster should be part of the embryo selection strategy before transfer.

Volume 106, Issue 7, Pages 1718-1724


Amanda Souza Setti, M.Sc., Rita Cássia Sávio Figueira, Ph.D., Daniela Paes de Almeida Ferreira Braga, D.V.M., M.Sc., Matheus de Castro Azevedo, B.Sc., Assumpto Iaconelli Jr., M.D., Edson Borges Jr., M.D., Ph.D.



To study whether embryos derived from oocytes presenting a smooth endoplasmic reticulum cluster (SERC) are less likely to develop into blastocysts and implant.


Transversal study.


Private university-affiliated in vitro fertilization (IVF) center.


Total of 7,609 oocytes obtained from 743 intracytoplasmic sperm injection (ICSI) cycles.


Oocytes split between the SERC-positive cycles (with at least one SERC-positive oocyte) and the SERC-negative cycles (only oocytes free of SERC).

Main Outcome Measure(s)

Embryo implantation.


A statistically significantly higher mean number of follicles (24.0 ± 10.5 vs. 19.6 ± 10.5), retrieved oocytes (17.8 ± 8.3 vs. 14.3 ± 8.0), and mature oocytes (13.5 ± 6.2 vs. 10.6 ± 5.9) were observed in the SERC-positive cycles as compared with SERC-negative cycles. The implantation rate was statistically significantly lower in SERC-positive cycles as compared with SERC-negative cycles (14.8% vs. 25.6%; odds ratio 0.61; 95% confidence interval, 0.44–0.86). When only cycles with in which none (0) or all the blastocysts transferred had implanted (100%) were analyzed, the mean implantation rate per transferred blastocyst in the SERC-negative group was 20.5%; no blastocysts derived from SERC-positive oocytes implanted.


The occurrence of SERC impairs embryo implantation. Careful oocyte observation that takes into account the presence of SERC should be part of embryo selection strategy before transfer.

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