Prenatal diagnosis following preimplantation genetic testing for monogenic conditions: a single centre record linkage study

PurposeProfessional bodies currently advise all pregnant individuals undertake confirmatory prenatal diagnostic testing following preimplantation genetic testing for monogenic conditions (PGT-M). We aimed to ascertain the uptake of prenatal diagnostic testing following PGT-M in a large single-centre population.MethodsThis observational linkage study was undertaken using routinely collected outcome data from PGT-M cycles performed at one of Australia's largest PGT-M providers and a statewide dataset of all prenatal samples undergoing cytogenetic analysis in Victoria, Australia, between 2015 and 2022.ResultsDuring the study period, there were 176 clinical pregnancies following the transfer of a PGT-M-tested embryo in 132 patients. Eleven patients undertook confirmatory prenatal diagnostic testing in 12 pregnancies, representing a confirmatory testing rate of 8.3% [95% CI: 4.7-14.3%] per patient and 6.8% [95% CI: 3.9-11.5%] per pregnancy. The 176 clinical pregnancies resulted in 154 (87.5%) live births and pregnancies ongoing at the time of reporting, 21 (11.9%) pregnancy losses <= 20 weeks gestation, and 1 (0.6%) stillbirth.ConclusionsMost patients who conceive following the transfer of a PGT-M-tested embryo do not undertake confirmatory prenatal diagnostic testing. The low uptake of confirmatory testing raises important considerations for genetic counselling for PGT-M and the acceptability of current clinical practice recommendations.