The clinical utility of genetic testing of tissues from pregnancy losses.

Abstract

To map the current testing being undertaken following pregnancy loss across the UK and to examine the clinical utility in terms of identifying a cause for the loss and in identifying couples at risk of an unbalanced liveborn child. Retrospective audit. UK, for the year 2014. An audit of 6465 referrals for genetic testing of tissue samples following pregnancy loss. Data were obtained by questionnaire from 15 UK regional genetics laboratories. Data were analysed with respect to gestational age, the presence of identified fetal anomalies, methodologies used, abnormality rates and the presence of a parental balanced rearrangement. Of 6465 referrals a genetic cause was identified in 22% of cases (before 12 weeks' gestation, in 47%; at 12-24 weeks, in 14%; after 24 weeks, in 6%). In 0.4% of cases a balanced parental rearrangement was identified where there was a risk of an affected liveborn child in a future pregnancy. Eighty percent of genetic imbalances identified were aneuploidy or triploidy and could be identified by quantitative fluorescence polymerase chain reaction alone. There was significant variation across the UK in acceptance criteria, testing strategies and thus level of resolution of testing. Genetic testing of tissues following pregnancy loss identifies a probable cause of fetal demise in 22% of cases, but it is of low clinical utility in identifying couples at risk of a future unbalanced liveborn child. A comprehensive multidisciplinary review is needed to develop proposals for an affordable and equitable service. UK audit of genetic testing of fetal loss shows variation in access to and resolution of analysis.