Research progress on the effect of oocyte smooth endoplasmic reticulum clusters on early embryo development and pregnancy outcome

With the clinical development and application of intracytoplasmic sperm injection(ICSI)technology in human assisted reproduction,the influence of oocyte quality on embryo development has been paid more and more attention.So far,there have been many reports on oocyte morphology affecting embryo development.It has been found in some works that the appearance of smooth endoplasmic reticulum clusters(SERC)in oocytes may affect the fertilization and embryo development of oocytes.However,with the increasing reports of SERC-containing oocytes obtained by in vitro fertilization and healthy offspring in recent years,there is still some controversy on whether to continue to use SERC-containing oocytes for the following assisted reproductive therapy in clinical practice.Based on this,this review aims to review the research progress of SERC in oocytes in recent years.

Effect of maternal age on the outcomes of in vitro fertilization and embryo transfer(IVF-ET)

This is a retrospective,observational study to evaluate the effect of maternal age on the outcomes of in vitro fertilization and embryo transfer(IVF-ET).11830 IVF-ET cycles from 10268 women were included.Four groups of different maternal age periods were compared.The groups were 21 30 years old group(4549 cycles),31-35 years old group(4424 cycles),36-40 years old group(2429 cycles),and over 40 years old group(428 cycles).The mean starting dose of Gn and mean total dose of Gn in each cycle were significantly higher(P<0.01),while the mean retrieved oocyte number was significantly lower(P<0.01) in groups of higher maternal age period than those in each of the lower groups.The biochemical pregnancy rate and the clinical pregnancy rate were significantly lower(P<0.01),while the miscarriage rate was significantly higher(P<0.01) in groups of higher maternal age period than those in the lower groups.No difference was found in two-pronuclear zygotes(2PN) rate and good quality embryo rate among different groups.Birth defect rate was also comparable in the born babies in different groups.In the group with patients' age over 40 years old,the pregnancy rate was 26.87%,the clinical pregnancy rate was 19.39%,while the miscarriage rate after clinical pregnancy was 36.14%.To draw the conclusion,patients with higher maternal age had worse IVF outcomes.In women of fertile age,patients between 20 and 30 years old have the best IVF outcomes.Patients over 40 years old have poor IVF outcome and high miscarriage rate,which suggested the necessity of preimplantation genetic screening(PGS).