Follicular Size and Ploidy Observational Study

The primary objective is to determine which follicle sizes generate the highest rate of euploid blastocysts.

The primary objective is to determine which follicle sizes generate the highest rate of euploid blastocysts.

Secondary objectives to be analysed between the different follicle sizes:

- The number of cumulus oocyte complexes (COCs) retrieved per aspirated follicle size
- The number of mature oocytes per COC retrieved (maturation rate)
- The number of normally fertilized oocytes per number of oocytes injected (fertilization rate)
- Embryo development up to the blastocyst stage
- Chromosomal status of the biopsied blastocysts
- Pregnancy rates after euploid blastocyst transfer
- Miscarriage rate after euploid blastocyst transfer

Most of the studies that looked at the relation between the follicular size and the developmental competence of the corresponding oocyte analysed normal responders with an average age of 35 years and normal BMI levels. However, during the last decades, a clear shift appeared in the patient population that present themselves for a fertility treatment. With many women delaying childbirth, we do not yet know how these advanced maternal age women may benefit from early or late trigger or from different follicular sizes.

Also, the rising prevalence of obesity may impact the follicular growth, which has not been analysed at the individual follicle size before.

For the above described reasons, we believe that the analysis of individual follicles and the developmental competence of the obtained oocyte, may guide us to improve individualized stimulation protocols for different subtypes of infertile patients. To guide us in this individualized process, this initial pilot study will be performed in a population of normal responders and will later be expanded to an infertile population with different characteristics.