Maternal and neonatal outcomes following blastocyst biopsy for PGT in single vitrified-warmed embryo transfer cycles

Research question: Does blastocyst biopsy for preimplantation genetic testing (PGT) increase the risk of adverse maternal and neonatal outcomes? Study design: Retrospective cohort study of 5097 single vitrified-warmed blastocyst transfer cycles from January 2016 to December 2018, with 2061 cycles in the biopsied group and 3036 cycles in the unbiopsied group enrolled in the analyses. Maternal and neonatal outcomes were compared between the two groups. Results: The live birth rate in the biopsied group (41.1%) was significantly higher than that in the unbiopsied group (35.6%, adjusted odds ratio [aOR] 1.27, 95% confidence interval [CI] 1.05-1.54, P = 0.012) after adjusting for maternal age, maternal body mass index, gravidity, parity, infertility diagnosis, timing of blastocyst transfer, blastocyst quality, regimen of endometrial preparation, endometrial thickness before transfer and treatment year. The rates of total pregnancy loss (25.4% versus 32.2%, aOR 0.69, 95% CI 0.52-0.9 1, P = 0.008) and early miscarriage (12.1% versus 17.3%, aOR 0.56, 95% CI 0.38-0.83, P = 0.004) were significantly lower in the biopsied group than in the unbiopsied group. No significant differences were found in sex ratio or the risks of hypertensive disorders in pregnancy, diabetes in pregnancy, placenta previa, preterm premature rupture of membranes, low birthweight, very low birthweight, macrosomia, small for gestational age, large for gestational age or birth defects between the two groups. When the subgroup analyses were conducted based on different types of PGT, similar patterns were found for all types. Conclusion: Blastocyst biopsy might not increase the risks of adverse maternal and neonatal outcomes in the short term.