Predictive value of cytoplasmic granulation patterns during in vitro fertilization in metaphase II oocytes: part II, donor oocyte cycles

Abstract

Objective: To determine whether the ooplasm granulation patterns of donor oocytes, like those of oocytes from poor-prognosis patients, are predictive of in vitro fertilization (IVF) outcomes.

Design: Retrospective cohort study.

Setting: Academically affiliated private clinical infertility and research center.

Patient(s): 770 fresh and 381 vitrified-thawed metaphase II oocytes from young donors (aged 21.0-34.6 years) used for IVF during 2017-2020.

Intervention(s): Determination of granulation patterns in every oocyte during intracytoplasmic sperm injection as fine, central, uneven, dispersed, and peripheral (thawed only).

Main outcome measure(s): Fertilization, pregnancy, and live birth rates in fresh and thawed donor oocytes. Both overall and known-outcome analyses were performed for pregnancy and live birth.

Result(s): In fresh donor oocytes, 2 pronuclei rates trended down from 96.1% to 90.2%, 88.9%, and 69.7% from fine to central, uneven, and dispersed granulations; overall pregnancy rates trended down from 50.4% to 29.0%, 17.7%, and 6.9%, as well as live birth rates (43.4%, 21.6%, 12.5%, and 6.4%), from fine to uneven, central, and dispersed granulations. Known pregnancy and known-live birth analyses showed similar findings. Thawed donor oocytes demonstrated similar trends in differences in fertilization, pregnancy, and live birth analyses with relatively worse outcomes. Peripheral granulation, unique to vitrification and thawing, always demonstrated the worst IVF outcomes. Moreover, granulation patterns were relatively disassociated from embryo morphological grades in fresh and largely disassociated in thawed donor oocytes.

Conclusion(s): Predictive values of oocyte granulation patterns for fertilization, pregnancy, and live birth in IVF cycles are even more pronounced in young donors than results in older poor-prognosis patients, further supporting integration of oocyte granulation patterns into embryo selection.

Keywords: Embryo selection; fertilization; live birth; ooplasm granulation; pregnancy.