PRODUCTS OF CONCEPTION (POC) TESTING OF OOCYTE DONOR-DERIVED PREGNANCIES: ACTIONABLE FINDINGS THAT MAY IMPACT MEDICAL MANAGEMENT AND RECURRENCE RISK

Products of conception (POC) testing is not routinely indicated for donor oocyte pregnancies, as lower aneuploidy rates are anticipated with lower maternal age (MA).1 Some chromosomal abnormalities are independent of MA and actionable including: triploidy of paternal origin or full paternal uniparental disomy (UPD) which can cause molar pregnancy and increased risk of gestational trophoblastic disease (GTD); and deletions/duplications (del/dups) that can be inherited and increase the risk of miscarriage or chromosomally abnormal offspring. This study reports the rates of these findings in POC testing with donor oocytes. Fresh POC and biological parental and/or gestational carrier samples received from April 2011-Feb 2020 were analyzed retrospectively. Genotyping was performed using Illumina Cyto12 single nucleotide polymorphism (SNP)-based microarrays with bioinformatics. Oocyte donor age was defined as ≤30 years. Of the 1641 POC cases using an oocyte donor, 208 (12.7%) results had maternal cell contamination or were incomplete and therefore were excluded. Of the remaining 1433 cases, 1054 (73.6%) were euploid, and 379 (26.4%) were abnormal, defined as having monosomy, trisomy, triploidy, tetraploidy, del/dups, UPD, and/or other complex abnormality.Table 1Abnormality Rates for Donor Oocyte CasesOverall TotalMaternalPaternalMixedUnknown*Aneuploid**, n (%)301 (79.4)238 (79.1)49 (16.3)6 (2.0)8 (2.7)Del/Dups (≥ 1 imbalance), n (%)32 (8.4)16 (50)5 (15.6)1 (3.1)11 (34.4)Triploidy, n (%)38 (10.0)34 (89.5)3 (7.9)n/a1 (2.6)Tetraploidy, n (%)1 (0.3)1 (100)000Full UPD, n (%)3 (0.8)03 (100)00Other Complex Abnormality, n (%)4 (1.1)0004 (100)*Unknown: mosaic abnormality of unknown parental origin or no biological parent sample submitted**Aneuploid: ≥ 1 monosomy and/or trisomy; excludes del/dups, triploidy, tetraploidy, UPD, complex abnormalities Open table in a new tab *Unknown: mosaic abnormality of unknown parental origin or no biological parent sample submitted **Aneuploid: ≥ 1 monosomy and/or trisomy; excludes del/dups, triploidy, tetraploidy, UPD, complex abnormalities Despite using donor oocytes in our cohort, most reported chromosomal anomalies were maternally derived. Almost 20% of abnormal POC results indicate the need for additional medical management to monitor for GTD (full paternal UPD, paternal triploidy) or parental genetic testing to accurately determine recurrence risk to offspring or donor oocytes (del/dups). This information underscores the importance of POC testing, and its ability to impact medical care and to assist in providing accurate counseling for patients and donors, even in the absence of advanced maternal age.