Agonist triggering in oocyte donation programs-Mini review.

Oocyte donation programs involve young and healthy women undergoing heavy ovarian stimulation protocols in order to yield good-quality oocytes for their respective recipient couples. These stimulation cycles were for many years beset by a serious and potentially lethal complication known as ovarian hyperstimulation syndrome (OHSS). The use of the short antagonist protocol not only is patient-friendly but also has halved the need for hospitalization due to OHSS sequelae. Moreover, the replacement of beta-human chorionic gonadotropin (b-hCG) with gonadotropin-releasing hormone agonist (GnRH-a) triggering has reduced OHSS occurrence significantly, almost eliminating its moderate to severe presentations. Despite differences in the dosage and type of GnRH-a used across different studies, a comparable number of mature oocytes retrieved, fertilization, blastulation, and pregnancy rates in egg recipients are seen when compared to hCG-triggered cycles. Nowadays, GnRH-a tend to be the triggering agents of choice in oocyte donation cycles, as they are effective and safe and reduce OHSS incidence. However, as GnRH-a triggering does not eliminate OHSS altogether, caution should be practiced in order to avoid unnecessary lengthy and heavy ovarian stimulation that could potentially compromise both the donor's wellbeing and the treatment's efficacy.

In Freeze-All Strategy, Cumulative Live Birth Rate (CLBR) Is Increasing According to the Number of Blastocysts Formed in Women <40 Undergoing Intracytoplasmic Sperm Injection (ICSI).

Background: Elective freezing of all embryos, followed by frozen-thawed ET cycles emerged to prevent risk of Ovarian Hyperstimulation Syndrome and to allow endometrium recovery after Controlled Ovarian Stimulation, leading to better IVF outcomes. Blastocyst Freeze-all policy can minimize the number of abnormal embryos and consequently failed ETs, but its efficacy in terms of cumulative rates has not been studied yet. Methods: A prospective cohort observational study was carried out in Assisting Nature, Center of Assisted Reproduction and Genetics, in Thessaloniki, Greece from January 2014 until December 2017. 244 patients- normal or high responders- underwent COS with recFSH and Freeze-all policy with blastocyst culture. The included patients were 18-39 years and achieved clinical pregnancy and/or live birth or had all their vitrified blastocysts transferred in subsequent frozen-thawed cycles. Women were divided into four groups (group A: 1-2 blastocysts frozen; group B: 3-4; group C: 5-6; group D ≥7 blastocysts frozen) or seven groups (group I: 1-2 blastocysts frozen, group II: 3, group III: 4, group IV: 5, group V: 6, group VI: 7; group VII: ≥8 blastocysts frozen), according to the numerical range or to the absolute number of vitrified blastocysts, respectively. Results: The main outcome of the study was the CLBR achieved by frozen-thawed ETs, according to the number of the vitrified blastocysts. Higher CLBR are expected, when at least 3 blastocysts are formed (group B: 65.2%) and at least 2 frozen-thawed ETs are performed, reaching highest rates (88%) by group D (≥7 vitrified blastocysts). Similarly, CLBR is significantly increasing with the absolute number of the vitrified blastocysts, ranging from 20%, when 1-2 blastocysts are vitrified (group I) to 82.4% when ≥8 blastocysts are available. Conclusions: A higher number of vitrified blastocysts is associated with higher CLBR in women <40 years old- normal/high responders- following Freeze-all policy. Adopting Freeze-all strategy after blastocyst culture can contribute to improve delivery outcome after IVF, in terms of CLBR. The number of the total cryopreserved blastocysts produced might reflect the quality of the oocyte and can successfully predict the pregnancy outcome. The blastulation rate can be a robust criterion to segment or not an IVF cycle.