Articles
Register for Ovarian Hyperstimulation Syndrome and Prophylactic Human Embryo Cryopreservation: Analysis of Reproductive Outcome Following Thawed Embryo Transfer
Eric Scott Sills1, Laura J McLoughlin2, Marc G Genton3, David J Walsh1, Graham D Coull1 and Anthony PH Walsh1
1Sims International Fertility Clinic/The Sims Institute, Dublin,
Ireland
2Faculty of Medical Sciences, University of Newcastle,
Newcastle-upon-Tyne, UK
3Department of Econometrics, University of Geneva, Geneva,
Switzerland
Journal of Ovarian Research 2008, 1:7doi:10.1186/1757-2215-1-7
Published: 6 November 2008
Research
Abstract
Objective
To review utilisation of elective embryo cryopreservation in the expectant
management of patients at risk for developing ovarian hyperstimulation syndrome
(OHSS), and report on reproductive outcome following transfer of thawed embryos.
Materials and methods
Medical records were reviewed for patients undergoing IVF from 2000–2008 to
identify cases at risk for OHSS where cryopreservation was electively performed
on all embryos at the 2 pn stage. Patient age, total number of oocytes
retrieved, number of 2 pn embryos cryopreserved, interval between retrieval and
thaw/transfer, number (and developmental stage) of embryos transferred (ET), and
delivery rate after IVF were recorded for all patients.
Results
From a total of 2892 IVF cycles undertaken during the study period, 51 IVF
cases (1.8%) were noted where follicle number exceeded 20 and pelvic fluid
collection was present. Elective embryo freeze was performed as OHSS prophylaxis
in each instance. Mean (± SD) age of these patients was 32 ± 3.8 yrs. Average
number of oocytes retrieved in this group was 23 ± 8.7, which after
fertilisation yielded an average of 14 ± 5.7 embryos cryopreserved per patient.
Thaw and ET was performed an average of 115 ± 65 d (range 30–377 d) after oocyte
retrieval with a mean of 2 ± 0.6 embryos transferred. Grow-out to blastocyst
stage was achieved in 88.2% of cases. Delivery/livebirth rate was 33.3% per
initiated cycle and 43.6% per transfer. Non-transferred blastocysts remained in
cryostorage for 24 of 51 patients (46.1%) after ET, with an average of 3 ± 3
blastocysts refrozen per patient.
Conclusion
OHSS prophylaxis was used in 1.8% of IVF cycles at this institution; no
serious OHSS complications were encountered during the study period. Management
based on elective 2 pn embryo cryopreservation with subsequent thaw and grow-out
to blastocyst stage for transfer did not appear to compromise embryo viability
or overall reproductive outcome. For these patients, immediate elective embryo
cryopreservation and delay of ET by as little as 30 d allowed for satisfactory
conclusion of the IVF sequence, yielding a livebirth-delivery rate (per ET)
>40%.
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© 2008 Sills et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative
Commons Attribution License
http://creativecommons.org/licenses/by/2.0 which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is
properly cited.
The electronic version of this article is the complete one and can be found online at: http://www.ovarianresearch.com/content/1/1/7
