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Blastocyst Aneuploidy as a Function of the Diameter of the Originating Ovarian Follicle

petri dish

Authors: Carrie Bedient, Ankita Raman, Forest Garner, Martha Aguirre, Chelsea Morrison, Shyni Thomas, Anika Bill, Bruce Shapiro

Objective: Assess relationships, if any, between embryo ploidy and the mean diameter of the follicle from which the oocyte originated.

Design: IRB-approved prospective observational cohort study.

Materials and Methods: Patients underwent routine ovarian stimulation with exogenous gonadotropins. During oocyte collection, follicle diameters were sonographically measured on two perpendicular axes, and the mean was calculated for each follicle.Embryos were group-cultured to the blastocyst stage according to mean follicle diameter (≤9.5, 10-12.5, 13-15.5, 16-18.5, 19-21.5, 22-24.5, 25-27.5, and ≥28mm).  Next-generation sequencing (NGS) followed trophectodermbiopsy. Chi-square analysis compared aneuploidy rates among follicle diameter groups.  Stepwise logistic regression was used to identify significant predictors of aneuploidy. P<0.05 was considered significant.

Results:There were 318 blastocysts derived from measured follicles that had definitive NGS results (normal or abnormal), while 4 embryos with no test result were excluded. Of the 318 included blastocysts, 169 had normal (euploid) copy numbers and 149 had abnormal (aneuploid) copy numbers.Chi-square analysis found no relationship between aneuploidy and follicle size group (P=0.46).  Among variables available for logistic regression, only patient age was retained in the logistic model (P=0.0020), while mean follicle diameter and blastocyst morphology parameters (blastocyst expansion, ICM, and trophectoderm quality)were not significant.

Conclusions: Among blastocysts selected for biopsy, the diameter of the originating follicle was not a significant predictor of embryo ploidy.

Support: None

Mean follicle diameter Blastocysts Euploid blastocysts
≤9.5mm 12 5 (41.7%)
10-12.5mm 32 17 (53.1%)
13-15.5mm 51 29 (56.9%)
16-18.5mm 71 42 (59.2%)
19-21.5mm 75 39 (52.0%)
22-24.5mm 52 21 (40.4%)
25-27.5mm 15 10 (66.7%)
≥28mm 10 6 (60.0%)
Total 318 169 (53.1%)