This study aims to investigate whether embryo ranking by a fully automated AI tool (iDAScore) results in a similar transfer-to-pregnancy compared to manual embryo ranking by an embryologist. IVF patients who are planned for a freeze-all approach (where all usable embryos are frozen and transferred in later transfer cycles) will be allocated to either the control (ranking by embryologist) or intervention arm (ranking by iDAScore). The frozen embryos will be warmed and transferred one by one, according to their assigned rank. We want to see if the average number of embryo transfers that is needed to achieve a clinical pregnancy (transfer-to-pregnancy) is similar in both groups.

The study population consists of IVF/ICSI patients scheduled for a freeze-all policy on day 5. Inclusion takes place on the day prior to oocyte retrieval, based on predefined inclusion criteria. Embryo culture is performed in an EmbryoScope+ time-lapse incubator. On day 5 of embryo development, the embryologist evaluates the embryos using the Gardner criteria, assessing expansion stage, inner cell mass (ICM), and trophectoderm (TE). All embryos meeting our in-house cryopreservation criteria are vitrified. Embryos not yet meeting the criteria remain in culture and are re-evaluated on day 6. Once at least two blastocysts meet the cryopreservation criteria on day 5 and/or day 6, the patient is randomized in the control or study arm.

In the control group, the embryologist manually ranks all freezable embryos according to the assigned Gardner scores, applying a standard prioritization scheme: day of cryopreservation > expansion stage > TE score > ICM score.

If multiple embryos share the same Gardner score, the embryologist looks at the full morphokinetics to establish a final ranking. The order of warming for subsequent frozen embryo transfer (FET) cycles follows this ranking: the embryo ranked 1 is transferred first. If no clinical pregnancy results, the embryo ranked 2 is transferred in the next FET cycle, and so on.

In the study group, the iDA score is retrieved for each freezable embryo. Embryos are ranked solely based on their iDA score, with the highest score assigned rank 1, and so on. The order of warming for subsequent FET cycles is determined exclusively by this ranking. As in the embryologist group, the embryo ranked 1 is transferred first, followed by rank 2 in case of no clinical pregnancy, and so on.

+/- 10 days after embryo transfer, an hCG blood test is performed. In case of a positive result, the pregnancy is monitored until the 7-week ultrasound, at which the presence of fetal heartbeat confirms a clinical pregnancy. Patients are followed for clinical pregnancy outcomes of FETs performed up to one year after oocyte retrieval, or until the pregnancy outcome of the last available embryo is known.

In both the study and control arm, all procedures follow the standard of care. The only difference between the groups is the method of embryo ranking-and therefore the order in which embryos will be transferred.

Inclusion Criteria:

• patients undergoing an ICSI/IVF treatment (with donor or own oocytes) that are planned for a 'freeze-all' strategy on day 5
• all types of sperm samples (ejaculated or testicular, fresh or frozen, partner or donor origin)
• Minimum 8 follicles (≥ 12 mm) on last follicular measurement before oocyte retrieval
• 18 ≤ Age ≤ 42 years
• 18 ≤ BMI ≤ 35 kg/m²
• Maximum third IVF/ICSI cycle
• Participants can be included only once in the trial

Exclusion Criteria:

• Embassy patients
• Use of frozen oocytes
• In vitro maturation (IVM) cycles
• Pre-implantation genetic Testing (PGT) cycles
• Proven untreated intra-uterine pathologies (e.g. Asherman syndrome, adenomysosis)
• Endometriosis stage 3/4

Only female participants can undergo an oocyte retrieval.