Zygotic splitting following embryo biopsy: a cohort study of 207 697 single-embryo transfers following IVF treatment.

Abstract

To evaluate the risk of monozygotic splitting with embryo biopsy during in vitro fertilisation (IVF). A cohort study. Anonymised assisted reproductive technology national data from the Human Fertilisation and Embryology Authority, UK. Women undergoing single-embryo transfer (SET) following either pre-implantation genetic testing (PGT) involving embryo biopsy or IVF without PGT. Data on women undergoing SET either following PGT and non-PGT IVF treatment in 2000-2016 were analysed to compare the risk of zygotic splitting and monozygotic twining. Logistic regression analysis was performed adjusting for potential confounders. Monozygotic spitting, monozygotic twin birth. Data comprising a total of 207 697 SET cycles (4544 following PGT and 203 153 following non-PGT IVF) were analysed. The live birth rate per embryo transfer was 31.9% (95% confidence interval [CI] 30.5-33.2%) following PGT and 26.9% (95% CI 26.7-27.1%) following non-PGT IVF. The incidence of zygotic splitting following PGT was 2.4% (95% CI 1.7-3.3%) versus 1.5% (95% CI 1.4-1.6%) following non-PGT IVF. There was a significantly higher risk of zygotic splitting with PGT versus non-PGT IVF cycles (odds ratio [OR] 1.64, 95% CI 1.19-2.27). The higher risk of zygotic splitting with PGT cycles remained significant after adjusting for potential confounders (adjusted OR 1.51, 95% CI 1.06-2.15). The present study demonstrated an increased risk of monozygotic splitting with embryo biopsy. Given the current sparse literature, it is important to accumulate further evidence to validate the findings. A likely increased risk of monozygotic splitting following embryo biopsy.