Human oocyte area is associated with preimplantation embryo usage and early embryo development: the Rotterdam Periconception Cohort

Rosalieke E Wiegel; Eleonora Rubini; Melek Rousian; Sam Schoenmakers; Joop S E Laven; Sten P Willemsen; Esther B Baart; Régine P M Steegers-Theunissen

doi:10.1007/s10815-023-02803-1

Human oocyte area is associated with preimplantation embryo usage and early embryo development: the Rotterdam Periconception Cohort

J Assist Reprod Genet. 2023 Jun;40(6):1495-1506. doi: 10.1007/s10815-023-02803-1. Epub 2023 May 2.

Authors

Rosalieke E Wiegel¹, Eleonora Rubini¹, Melek Rousian¹, Sam Schoenmakers¹, Joop S E Laven¹, Sten P Willemsen^{1

2}, Esther B Baart^{1

3}, Régine P M Steegers-Theunissen⁴

Affiliations

¹ Department of Obstetrics and Gynecology, Erasmus MC, University Medical Center, 3015 GD, Rotterdam, The Netherlands.
² Department of Biostatistics, Erasmus MC, University Medical Center, 3015 GD, Rotterdam, The Netherlands.
³ Department of Developmental Biology, Erasmus MC, University Medical Center, 3015 GD, Rotterdam, The Netherlands.
⁴ Department of Obstetrics and Gynecology, Erasmus MC, University Medical Center, 3015 GD, Rotterdam, The Netherlands. r.steegers@erasmusmc.nl.

Abstract

Purpose: To investigate the association between oocyte area and fertilization rate, embryo usage, and preimplantation embryo development in order to establish if oocyte area can be a marker for optimal early embryo development.

Methods: From 2017 to 2020, 378 couples with an indication for IVF (n = 124) or ICSI (n = 254) were included preconceptionally in the Rotterdam Periconception Cohort. Resulting oocytes (n = 2810) were fertilized and submitted to time-lapse embryo culture. Oocyte area was measured at the moment of fertilization (t0), pronuclear appearance (tPNa), and fading (tPNf). Fertilization rate, embryo usage and quality, and embryo morphokinetics from 2-cell stage to expanded blastocyst stage (t2-tEB) were used as outcome measures in association with oocyte area. Oocytes were termed "used" if they were fertilized and embryo development resulted in transfer or cryopreservation, and otherwise termed "discarded". Analyses were adjusted for relevant confounders.

Results: Oocyte area decreased from t0 to tPNf after IVF and ICSI, and oocytes with larger area shrank faster (β - 12.6 µm²/h, 95%CI - 14.6; - 10.5, p < 0.001). Oocytes that resulted in a used embryo were larger at all time-points and reached tPNf faster than oocytes that fertilized but were discarded (oocyte area at tPNf in used 9864 ± 595 µm² versus discarded 9679 ± 673 µm², p < 0.001, tPNf in used 23.6 ± 3.2 h versus discarded 25.6 ± 5.9 h, p < 0.001). Larger oocytes had higher odds of being used (oocyte area at tPNf OR_used 1.669, 95%CI 1.336; 2.085, p < 0.001), were associated with faster embryo development up to the morula stage (e.g., t9 β - 0.131 min, 95%CI - 0.237; - 0.025, p = 0.016) and higher ICM quality.

Conclusion: Oocyte area is an informative marker for the preimplantation development of the embryo, as a larger oocyte area is associated with higher quality, faster developing embryos, and higher chance of being used. Identifying determinants associated with oocyte and embryo viability and quality could contribute to improved preconception care and subsequently healthy pregnancies.

Keywords: Assisted reproduction; Early life course; In vitro fertilization; Morphological marker; Oocyte area.

MeSH terms

Blastocyst
Embryonic Development
Female
Fertilization in Vitro* / methods
Fertilization*
Humans
Oocytes
Pregnancy

Grants and funding

No 812660./H2020 Marie Skłodowska-Curie Actions