P–383 Cytogenetic analysis of products of conception from miscarriages following natural conception and IVF pregnancy: a comparative study

Abstract

Abstract Study question Do cytogenetic results from products of conception from miscarriages differ from patients conceiving by natural conception versus IVF? Summary answer: Cytogenetic results were similar, with no statistical difference from miscarriages following natural conception and assisted conception. What is known already Cytogenetic sampling of products of conception (POC) following recurrent miscarriages (RM) are recommended to rule out parental chromosomal rearrangements. The RCOG recommends cytogenetic testing in cases of recurrent miscarriages (3 consecutive miscarriages). However some units routinely request cytogenetic analysis following a single miscarriage following an IVF pregnancy. There is no evidence to support the routine sampling of POCs following assisted conception. Study design, size, duration: Retrospective cohort study of 117 cytogenetic samples, followed up by the outcome of parental karyotyping if applicable. Patients were categorised based on mode of conception into natural conception (NC) with recurrent miscarriages (≥3) or one miscarriage following IVF. Data collected between 2018–2020. Primary Outcome measure: Presence and type of cytogenetic abnormality; individual parental targeted G-band karyotyping result. Participants/materials, setting, methods: A total of 117 cytogenetic results were reviewed, of which 35 were unsuitable for analysis due to contamination (Total n = 79: NC = 60, IVF = 19). Main results and the role of chance: Cytogenetic analysis showed abnormal results in 59% of miscarriages following natural conception and 53% of miscarriages from IVF pregnancy (p = 0.46). Abnormal cytogenetic results were mainly sporadic. Trisomy 16 was the commonest abnormality in both groups. Others included Trisomy 15, 22, 21, 8, 13, 5, 9, 10, 14, 18, single X (Turner’s), all occurring in the same frequency in both groups. As expected 35 out of 45 abnormal cytogenetic results occurred with a maternal age greater than 35 years. One couple from the NC group were referred to a geneticist for a Trisomy 9 imbalance. All other parental karyotyping results were normal. Limitations, reasons for caution This study contains a small sample size, and would benefit from further data collection to account for a percentage of samples being inadequate for analysis. Wider implications of the findings: Cytogenetic results were similar from miscarriages following natural conception and assisted conception. IVF does not increase the risk of miscarriage from abnormal embryonic karyotype. Routine cytogenetic testing following one miscarriage in patients undergoing IVF is not cost effective. Trial registration number Not applicable