1. A HURDLE IN THE EGG FREEZING RACE: COMPARISON OF DONOR AND AUTOLOGOUS OOCYTE CRYOPRESERVATION OUTCOMES
NYU Langone Fertility Center
Sarah Druckenmiller, Patty Ann Labella, Shannon DeVore, James Grifo, Brooke Hodes-Wertz, Nicole Noyes
OBJECTIVE
Oocyte cryopreservation is now a mainstream fertility preservation option, and many women are asking about the chance of live birth with this new technology. Unfortunately, minimal data is available as most women who have undergone oocyte cryopreservation have not yet returned for thaw. Further, much of our knowledge is based on donor oocyte cryopreservation, which may be superior to autologous oocyte cryopreservation. Thus, our aim was to compare donor and autologous oocyte cryopreservation thaw outcomes.
TABLE. Outcomes of oocyte cryopreservation cycles.
FIGURE. Outcomes of oocyte cryopreservation cycles.
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Group
Donor oocyte cryopreservation
(n = 119 pts, 131 thaws,
158 transfers)
All autologous oocyte cryopreservation <43y
(n= 123 pts,
137 thaws,
92 transfers)
Autologous oocyte cryopreservation <35y at cryo
(n= 23 pts,
24 thaws,
16 transfers)
P Values
Median age (IQR)
26 (24-29)a
38 (36-39)
33 (30-34)b
a-b
No. MII oocytes thawed
(median / cycle, IQR)
1138
(8, 6-10)c
1698
(11, 8-16)d
381
(13, 11-21)e
c-d
c-e
No. MII oocytes survived
1001/1138
(88%)f
1330/1698
(78%)g
300/381
(79%)h
f-g .0001
f-h .0001
No. 2-PN fertilization
759/1138
(67%)i
901/1698
(53%)j
230/381
(60%)k
i-j .0001
i-k .03
No. of morulae + blastocysts
91+373
= 464
= 395
43+83
= 126
Morula + blastocyst formation rate
464/759
(61%)l
395/901
(44%)m
126/230
(55%)n
l-m .0001
l-n .09
Blastocyst formation rate
373/759
(49%)o
246/901
(27%)p
83/230
(36%)q
o-p .0001
o-q .0005
Total no. embryos transferred
215
(1, 1-2)
182 41
(2, 2-3)
Implantation rate
102/215
(47%)r
54/182
(30%)s
13/41
(32%)t
r-s .0003
r-t .09
Ongoing / live birth rate for all transfers
84/158
(53%)u
38/92
(41%)v
9/16
(56%)w
u-v .09
u-w 1
No. thaw cycles with no transfer (%)
9/131
(7%)x
47/137
(34%)y
8/24
(33%)z
x-y .0001
x-z .001
Percent (%)
RESULTS
See Table. Oocyte cryopreservation cycles included 131 donor thaws (119 recipients, median donor age 26, range 21-31) and 137 autologous thaws (123 pts, median age 38, range 25-42), including the subgroup of 24 autologous <35y thaws (23 patients, median age 33, range 25-34). As expected, donors were younger than autologous patients (p<.0001) and fewer MII oocytes per cycle were thawed in donor cycles (median 8) than in all autologous cycles (median 11; p<.0001) or autologous <35y cycles (median 13; p<.0001). Oocyte survival, 2-PN fertilization and blastocyst formation rates were higher in donor than all autologous (p<.0001) and autologous <35y (p<0.03) cycles, and more all-autologous and autologous <35y cycles had no suitable blastocysts for transfer compared to donor cycles (34% and 33% vs. 7%; p<.01). However, in cycles with blastocysts for transfer, live birth rates were not different between donor and autologous <35y cycles (p=1); albeit, in autologous <35y patients, an additional blastocyst was transferred on average per cycle. Multiple birth rates in the donor, all autologous, and autologous <35y groups were 5/84 (6%), 7/38 (18%), and 2/9 (22%), respectively.
DESIGN
Retrospective cohort study
MATERIALS & METHODS
We reviewed all donor and autologous oocyte cryopreservation thaw cycles from October January 2017 at a large university-based fertility center. Exclusion criteria included use of PGD/PGS, day-3 embryo transfers, and age at retrieval >43y. Data was mined for: number of retrieved / thawed / surviving oocytes, 2-pronuclear (2PN) fertilization, embryo development, implantation and ongoing pregnancy / live birth rates. Fischer’s exact and Mood’s median tests were used for statistics.
CONCLUSIONS
As women increasingly rely on autologous oocyte cryopreservation for fertility preservation, it is critical to provide realistic expectations about outcomes. Developmental parameters for autologous oocyte cryopreservation were inferior to donor oocyte cryopreservation, resulting in production of fewer blastocysts and a higher proportion of patients with no embryos for transfer. However, in those achieving embryo transfer, live-birth outcomes in autologous <35y vs. donor groups appear comparable, although with an additional blastocyst being transferred on average per cycle in the autologous <35y group. Thus, donor thaw data is not an appropriate counselling tool for women pursuing autologous oocyte cryopreservation; only autologous thaw data should be used.