Efficiency of elective oocyte vitrification for reproductive aging women seeking fertility preservation to delay motherhood

Abstract

There is an increasing demand for fertility preservation for women who wish to delay motherhood for a variety of non-medical reasons. The efficiency and safety of oocyte vitrification allows women the opportunity to conceive in the future with their own genetic offspring. The aim of this study was to analyze the efficacy of oocyte vitrification techniques in preserving female fertility for reproductive aging women. Retrospective matched cohort study. Female patients (n=98) that underwent an elective autologous oocyte vitrification cycle for fertility preservation (mean maternal age = 37.4±3.9 years) and returned to undergo in vitro fertilization (IVF) at a later date, were directly compared to maternally aged-matched female patients that underwent IVF using fresh autologous oocytes. Mature oocytes were vitrified using the Cryotop method following standard controlled ovarian stimulation. All normally fertilized embryos were cultured to the blastocyst stage prior to embryo vitrification. Statistical analysis included Students t-test and Fishers exact test where appropriate, significance at P<0.05. Fertility preservation patients (n=98) returned for an oocyte warming cycle at a mean maternal age of 40.7±4.6 years, representing on average, three years and three months after oocyte vitrification. IVF outcomes with vitrified oocytes were significantly reduced compared to maternally age-matched infertility patients utilizing fresh autologous oocytes (Table 1). Nevertheless, 84% of oocytes survived vitrification resulting in 3.8 usable blastocysts per elective fertility preservation patient (Table 1). To date, there have been 72 frozen embryo transfers from these vitrified oocytes that have resulted in a respectable 51.4% live birth rate. Even though this clinical outcome is reduced compared to FETs with fresh oocytes, only 76.4% of the fertility preservation cycles underwent preimplantation genetic testing for aneuploidy (PGT-A) (Table 1). In conclusion, women in their mid-late thirties seeking elective oocyte vitrification for fertility preservation can expect good IVF outcomes when they return in their early forties. Although these outcomes are lower than if they had utilized their own fresh oocytes at the time of oocyte vitrification, they can be presumed to be higher than if they had initiated treatment in their early forties without fertility preservation.Table 1Fresh OocytesVitrified OocytesMean # oocytes retrieved or warmed19.7±10.015.2±8.7*Mean # oocytes survived post warm (%)N/A12.4±7.7 (84%)Mean # oocytes fertilized11.7±6.18.9±5.8*Mean # usable blastocysts (%)6.2 (57%)3.8 (39%*)Live birth rate (%)67.7%51.4%*PGT-A cycles (%)100%76.4%*P<0.05 Open table in a new tab