JBRA Assist. Reprod. 2025;29(Suppl 1):28-28
POSTER PRESENTATION
doi: 10.5935/1518-0557.20250082
1Fertya Medicina Reproductiva, Grupo Oroño - Rosario - Argentina
Objective: Determine the number of mature oocytes in metaphase II (MII) needed to obtain at least one euploid blastocyst regarding female age in In vitro Fertilization (IVF) cycles.
Methods: Descriptive, observational, cohort, retrospective study. Analysis of Intracytoplasmic Sperm Injection (ICSI) cycles from women with their own oocytes were only select with posterior preimplantation genetic test for aneuploidies (PGT-A) performed at Fertya Medicina Reproductiva, Rosario, over a five-year period (2019-2024). A multiple linear regression model was designed to predict the number of euploid embryos based on age group and MII number. A logistic regression model was designed to predict the minimum MII number required to obtain at least one euploid embryo. A p-value of less than 0.05 was considered statistically significant.
Results: A total of 323 IVF PGT-A cycles were performed in the study period in the evaluated population. The patients were divided according to age into three categories: under 35 years old (n=49), between 35 and 39 years old (n=135), and 40 years old or more (n=136). According to our model, in the group under 35 years old for each mature oocyte, one euploid embryo is obtained (p<0.0001). At least 6 oocytes MII would be required in the 35 to 39 years old group to guarantee a euploid embryo (p=0.0123), whereas at least 12 oocytes MII in the 40 year old and older group (p=0.0221) in IVF cycles (R2=0.61). When analysing the probability calculator with a logistic model, at least 12 oocytes MII would be required in the 40 years old or more group to guarantee a euploid embryo (p<0.0001) and the remaining groups would have no restrictions (model accuracy=0.68). This model was adjusted to predict the presence of euploid embryos, concluding that each additional mature oocyte increased the probability of having at least one euploid embryo by approximately 10.8% holding the age constant. This predictor is highly significant (p = 0.00079), suggesting that MII strongly influences the presence of euploid embryos.
Conclusion: Our results show a preliminary model capable of predicting the number of mature oocytes needed to obtain at least one euploid blastocyst according to female age in IVF cycles. Both regression models demonstrate moderate-high values and performance with highly predictive values. The number of MII needed to obtain one euploid blastocyst increased with age, needing at least 1, 6 and 12 mature oocytes in each group respectively to obtain a normal embryo. This model could help with decision making in those patients of advanced maternal age seeking infertility treatment who present significantly higher embryo aneuploidy rates and cannot afford to undergo PGT-A. This data may help clinicians to propose the best strategy for each patient and understand their likelihood of obtaining an euploid blastocyst.