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

Abstract

ObjectiveTo 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 methodsMedical 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.ResultsFrom 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.ConclusionOHSS 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%.

Pronuclear embryo cryopreservation experience: outcomes for reducing the risk of ovarian hyperstimulation syndrome and for fertility preservation in cancer patients

“…These studies, however, are limited by a lack of a comparison group [15] or details of the comparison group [16][17][18][19][20]. The choice of comparison group for this study is not necessarily to serve as a control, but is provided only to provide the background for the center's general practice and IVF outcomes.…”

“…dosage or type of medications [9,10], administration of intravenous albumin [11,12], dopamine agonists [13,14] and avoidance of ET, and thus pregnancy, immediately after stimulation with freezing of embryos for subsequent use [12,[15][16][17][18][19][20][21][22][23].…”

Correlation between embryological factors and pregnancy rate: development of an embryo score in a cryopreservation programme

“…Other significant advantages include the possibility of delaying embryo transfer, thereby enabling the assessment of infectious diseases, the possibility of performing unsynchronised embryo donations and, in some cases, of preventing ovarian hyperstimulation syndrome (OHSS) [7,8].…”

Prevention and Treatment of Ovarian Hyperstimulation Syndrome

“…Sills et al in 2008 analyzed outcomes in patients undergoing elective embryo cryopreservation to prophylax against the development of OHSS (Sills ES et al, 2008).…”