Ovarian hyperstimulation syndrome and prophylactic human embryo cryopreservation: Analysis of reproductive outcome following thawed embryo transfer

Eric Scott Sills, Laura J. McLoughlin, Marc G. Genton, David J. Walsh, Graham D. Coull, Anthony P.H. Walsh

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review


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. Growout 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%.

Original languageEnglish (US)
Title of host publicationCurrent Research in Embryology
PublisherApple Academic Press
Number of pages10
ISBN (Electronic)9781466559905
ISBN (Print)9781926692814
StatePublished - Jan 1 2011

Bibliographical note

Publisher Copyright:
© 2008 Sills et al.; licensee BioMed Central Ltd.

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology


Dive into the research topics of 'Ovarian hyperstimulation syndrome and prophylactic human embryo cryopreservation: Analysis of reproductive outcome following thawed embryo transfer'. Together they form a unique fingerprint.

Cite this