P-205 Blastocyst derived from oocytes with smooth endoplasmic reticulum aggregates (SERa) has similar clinical and perinatal outcomes with those of oocytes without SER
Authors: Arichi A , Yorimitu T , Omura N , Ito K , Komine H , Kudo Y , Shimizu Y , Kawamura T , Ohara M , Sasaki H , Honma S , Hasui M , Takemura Y , Teraoka K , Ishikawa T 
Published: June 2022

Study question

This study was to investigate effect of SERa on the fertilization rate, embryonic development after ICSI, and clinical and perinatal outcomes after single blastocyst transfer.

Summary answer

SERa (+) derived embryo can be selected as embryos for transfer when no available SERa (-) derived embryos.

What is known already

Based on findings that the risk of congenital abnormalities in the newborn is higher in ovum with SERa in the cytoplasm, the Istanbul consensus workshop at the 2011 meeting of the ESHRE recommended against fertilizing ovum with SERa due to these risks. However, there have been several reports of healthy infants born from embryos derived from SERa, suggesting that, while more long-term follow-up is necessary, healthy births are possible from such embryos. In 2017, the 2011 recommendations were reviewed in the Alpha/ESHRE consensus (Vienna), which said the approach should be determined on a case-by-case basis.

Study design, size, duration

We retrospectively investigated 23,007 oocytes which was retrieved between January 2016 and March 2020. Of these, 1,038 oocytes (4.5%) with visible SERa comprised SERa (+), while 21,969 oocytes (95.5%) without SERa comprised SERa (-).

Participants/materials, setting, methods

SERa were observed under the microscopy after denudation. The rate of fertilization, good-quality day-3 embryos, good-quality day-5 blastocysts, and day-5, 6 or 7 blastocysts were evaluated for both groups. We also compared the rate of clinical pregnancy, live birth, miscarriage, and birth defects in single blastocyst transfer between SERa (+) derived 114 blastocysts and SERa (-) derived 6,290 blastocysts from January 2016 and December 2018.

Main results and the role of chance

The results are shown. 2PN fertilization rate outcomes after ICSI (SERa(-) eggs vs. SERa(+)eggs),81.4%(17,873/21,969) vs.79.4% (823/1,038),and good-quality day3 rate was 61.1%(10,927/17,873)vs.60.9% (501/823) which was not significantly different. Good-quality day5 blastocyst rate was 46.5% (7,876/16,955) vs. 39.8%(304/763), and day 5 blastocyst success rate was 60.8% (10,317/16,955) vs.54.3% (414/763), which were both significantly lower with SERa(+). (P &lt; 0.001) The day 6 blastocyst success rate was 69.9% (11,849/16,955) vs. 65.5% (500/763) (P = 0.01), and the day 7 blastocyst success rate was 70.9% (12,024/16,955) vs. 67.5% (515/763) (P = 0.04), which were all significantly lower with SERa(+).The clinical pregnancy rate was 39.4% (2,481/6,290) vs. 35.1% (40/114), the live birth rate was 27.7% (1,745/6,290) vs. 26.3% (30/114), and the miscarriage rate was 27.5% (683/2,481) vs. 20.0% (8/40) and the congenital abnormality rate was 1.6% (29/1,757) vs. 0% (0/30) for SERa(-) embryos and SERa(+) embryos, respectively, which were not significantly different. Blastocyst derived from oocytes with SERa has similar clinical and perinatal outcomes with those of oocytes without SERa. Significant differences were examined using the chi-squared test, with p &lt; 0.05, indicating a significant difference.

Limitations, reasons for caution

Embryos derived SERa (+) were transferred when the patient did not want any more oocytes retrievals, no embryos derived SERa (-) were available, and only if the couple desired embryo transfer after the problems associated with SERa (+) embryos were fully explained.

Wider implications of the findings

To the best of our knowledge, this study is the largest number of live births investigating the outcome of SERa (+) derived embryos. SERa (+) derived embryo can be selected as embryos for transfer when no available SERa (-) derived embryos.

Trial registration number

Not Applicable