Elective cryopreservation of all pronucleate embryos in women at risk of ovarian hyperstimulation syndrome: efficiency and safety

Abstract

In a prospective randomized study, we analysed 125 patients at risk of ovarian hyperstimulation syndrome (OHSS), selected in the period between January 1996 and July 1997. All the patients had blood oestradiol concentration >/=1500 pg/ml on the day of human chorionic gonadotrophin (HCG) administration and >/=15 oocytes were collected. The patients were matched in two groups: group A, control group (n = 67), had fresh embryo transfers; group B (n = 58) had cryopreservation of all obtained pronucleate embryos. Pregnancy, live birth rates and the incidence of OHSS were compared between the two groups. There were no significant differences in terms of pregnancies per patient (46.3 versus 48.3%) and live birth rates (38. 8 versus 39.6%). No cases of OHSS occurred in group B, while four patients developed the syndrome in group A. The implantation rate was slightly but not significantly lower in group B (chi2 = 1.03). These results suggest that elective cryopreservation of all zygotes might prevent the risk of OHSS in patients undergoing IVF treatment. In contrast to what has been reported by other authors, our results show that the elective cryopreservation of zygotes does not affect pregnancy and live birth rates.

RETRACTED ARTICLE: Can fresh embryo transfers be replaced by cryopreserved-thawed embryo transfers in assisted reproductive cycles? A randomized controlled trial

“…A trend towards higher multiple pregnancy rate was also noted in FET cycles. Two previous studies have compared cryopreservation of all embryos with either human albumin or fresh ET and in the former, higher pregnancy rate was found in FET group [16] and in the latter no difference was found [17].…”

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.…”

“…Their results showed a similar incidence of OHSS but significantly higher PR in the cryopreservation group. Ferraretti et al [15] demonstrated that the PR and LBR rate among patients who underwent subsequent thaw of cryopreserved embryos was similar to those who underwent fresh transfer. There were no cases of OHSS among the 58 patients who underwent cryopreservation with subsequent transfer of thawed embryos, and there were 4 patients among 67 who developed OHSS in the control group.…”

“…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].…”

Factors affecting thawed oocyte viability suggest a customized policy of embryo transfer

“…In all, 371 thawing cycles were performed by administration of hormonal replacement therapy consisting of estradiol valerate (Progynova; Schering, Milan, Italy) at 2 mg/d from day 1 to day 5 of the menstrual cycle, 4 mg/d from day 6 to day 10, 6 mg/d from day 11 to day 13, and 4 mg/d from day 14. From day 15, 50 mg/d of P was given, and the dose was increased to 100 mg/d from day 17 (33).…”