Trophectoderm biopsy is associated with lower risks of moderate to extreme preterm births and low birth weights: a sart cors analysis of 45,712 singleton live births fromfrozen blastocyst transfers

To compare neonatal birth weights and preterm deliveries of singleton live births from vitrified-thawed blastocyst transfers with or without trophectoderm biopsy for preimplantation genetic testing (PGT). This is a retrospective cohort study of 45,712 singleton live births from vitrified-thawed blastocyst transfer cycles reported by SART member clinics between 2014-2017. Perinatal outcomes after trophectoderm biopsy for PGT were compared to those of pregnancies resulting from transfers of vitrified-thawed blastocysts without trophectoderm biopsy. Adverse perinatal outcomes analyzed include small for gestational age (SGA), large for gestational age (LGA), low birth weight (LBW) < 2500g, very low birth weight (VLBW) < 1500g, extremely low birth weight (ELBW) < 1000g, preterm births (PTB) < 37 weeks, moderate preterm births < 34 weeks, and extremely preterm births < 28 weeks. Multivariable regression analyses via general estimating equations were performed to account for multiple cycles per individual. Models were adjusted for maternal age, body mass index (BMI), obstetric history, tobacco use, race, infertility diagnoses, number of blastocysts transferred, and maximum pre-cycle follicle stimulating hormone (FSH) level. Of the 45,712 vitrified-thawed blastocyst transfer cycles resulting in singleton live births, 21,584 involved trophectoderm biopsy for PGT and the remaining 24,128 did not. Women in the trophectoderm biopsy group were older and more likely to have prior pregnancies, deliveries, and history of spontaneous abortions. Tobacco use, diminished ovarian reserve, and recurrent pregnancy loss were also more prevalent in the trophectoderm biopsy group. Trophectoderm biopsy was not associated with SGA (aOR 0.97, 95% CI 0.85-1.12, p-value 0.72) or LGA newborns (aOR 0.97, 95% CI 0.85-1.12, p-value 0.72). Risk of preterm births < 37 weeks gestation was similar between the biopsy and non-biopsy groups (aOR 0.93, 95% CI 0.85-1.02, p-value 0.11). Trophectoderm biopsy was associated with a significantly lower risk of LBW (aOR 0.80, 95% CI 0.70-0.92, p-value <0.001), VLBW (aOR 0.62, 95% CI 0.46-0.83, p-value <0.001), ELBW (aOR 0.48, 95% CI 0.31-0.74, p-value <0.001), moderate PTB < 34 weeks (aOR 0.76, 95% CI 0.64-0.91, p-value 0.003), and extreme PTB < 28 weeks (aOR 0.63, 95% CI 0.43-0.92, p-value 0.017). Trophectoderm biopsy is not associated with increased risks of SGA, LGA, or late PTB, and is associated with lower risks of LBW, VLBW, ELBW from moderate and extreme PTB.