Developmental potential of immature human oocytes aspirated after controlled ovarian stimulation

Rachel S Mandelbaum; Michael S Awadalla; Meghan B Smith; Caroline J Violette; Brittany L Klooster; Rachel B Danis; Lynda K McGinnis; Jacqueline R Ho; Kristin A Bendikson; Richard J Paulson; Ali Ahmady

doi:10.1007/s10815-021-02253-7

Developmental potential of immature human oocytes aspirated after controlled ovarian stimulation

J Assist Reprod Genet. 2021 Sep;38(9):2291-2299. doi: 10.1007/s10815-021-02253-7. Epub 2021 Jun 24.

Authors

Rachel S Mandelbaum^{1

2}, Michael S Awadalla^{1

2}, Meghan B Smith^{1

2}, Caroline J Violette¹, Brittany L Klooster¹, Rachel B Danis^{1

2}, Lynda K McGinnis¹, Jacqueline R Ho^{1

2}, Kristin A Bendikson^{1

2}, Richard J Paulson^{1

2}, Ali Ahmady^{3

4}

Affiliations

¹ Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
² USC Fertility, 1127 Wilshire Boulevard Suite 1400, Los Angeles, CA, 90017, USA.
³ Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA. ali.ahmady@med.usc.edu.
⁴ USC Fertility, 1127 Wilshire Boulevard Suite 1400, Los Angeles, CA, 90017, USA. ali.ahmady@med.usc.edu.

Abstract

Purpose: Intracytoplasmic sperm injection (ICSI) for initially immature oocytes that mature in vitro is controversial and practice varies widely. While it may increase the number of usable embryos, it may also be time-intensive and potentially low-yield. This study sought to elucidate which patients may benefit from ICSI of initially immature oocytes that matured in vitro.

Methods: A retrospective study comparing fertilization, cleavage, blastulation, and embryo usage rates between sibling initially immature and mature oocytes that underwent ICSI between 2015 and 2019 was performed. Outcomes of initially immature oocytes were stratified by initial maturation stage, timing of progression to metaphase II (MII) in vitro, percentage of mature oocytes in the cycle, and female age.

Results: Ten thousand eight hundred seventeen oocytes from 889 cycles were included. Of 3137 (29.0%) initially immature oocytes, 418 (13.3%) reached MII later on the day of retrieval (day 0) and 1493 (47.6%) on day 1. Overall, embryos originating from initially immature oocytes had lower cleavage and blastulation rates compared to those from initially mature oocytes (P<0.05, all groups). However, embryos from oocytes that matured later on day 0 comprised a unique subset that had clinically similar cleavage (75% vs 80%, RR 0.93, P=0.047) and blastulation rates (41% vs 50%, RR 0.81, P=0.024) compared to initially mature oocytes. Women with low percentages of mature oocytes in the cycle overall and women ≥40 in cleavage cycles derived the highest relative benefit from the use of immature oocytes.

Conclusion: ICSI of immature oocytes, particularly those that mature later on the day of retrieval, may improve numbers of usable embryos. This study supports routine reassessment of immature oocytes for progression to MII and ICSI on day 0. An additional reassessment on day 1 may also be of use in older women or those with low percentage of mature oocytes.

Keywords: Controlled ovarian stimulation; Immature oocytes; In vitro maturation; Intracytoplasmic sperm injection.

MeSH terms

Adult
Embryo Transfer
Embryonic Development*
Female
Fertilization in Vitro / methods*
Humans
In Vitro Oocyte Maturation Techniques / methods*
Oocytes / cytology*
Oogenesis*
Ovulation Induction / methods*
Retrospective Studies
Sperm Injections, Intracytoplasmic / methods*