O-050 The impact of embryo biopsy on obstetric and neonatal outcomes
Authors: Sites S 
Published: June 2023

Abstract

Background
Preimplantation genetic testing of embryos (PGT) was performed first in 1990 to prevent the transmission of X-linked disease. Since then, the technique has improved to include couples who are both carriers of the same autosomal recessive disorder, to those with balanced translocations having recurrent pregnancy loss, and to women with advanced maternal age who are at higher risk for having aneuploid embryos. Originally, PGT involved biopsy of the polar body or of one blastomere of a cleavage stage embryo for diagnosis. The contemporary practice of PGT involves the culture of embryos to the blastocyst stage (5-7 days after fertilization), with biopsy of several trophectoderm cells that would become the placenta, transport of biopsy tissue off-site for genetic analysis, and cryopreservation of blastocysts until biopsy results are available. A single euploid embryo is then transferred into the uterus as a frozen embryo transfer.

Objective
We sought to determine if removal of these cells for preimplantation genetic testing was associated with adverse obstetrical or neonatal outcomes after frozen-thawed single embryo transfer compared to frozen-thawed single embryo transfer without biopsy. Further, we review other studies of contemporary practice of PGT to draw conclusions about the safety of the practice.

Study design
We linked assisted reproductive technology surveillance data from the Society for Assisted Reproductive Technology Clinic Outcome Reporting System to birth certificates and maternal and neonatal hospitalization discharge diagnoses in Massachusetts, USA, from 2014-2017, considering singleton births after frozen-thawed single embryo transfer. We compared outcomes of cycles having embryo biopsy (n = 585) to those having no biopsy (n = 2,191), adjusting for mother’s age, race, education, parity, body mass index, birth year, insurance, and all infertility diagnoses (Sites CK et al, Am J Obstet Gynecol 2021;225:285.e1-7).

Results
With no biopsy used as the reference, we found no differences between no biopsy and biopsy groups with respect to preeclampsia, pregnancy-induced hypertension, placental disorders (placental abruption, placenta previa, placenta accreta, placenta increta, and placenta percreta), preterm birth, low birthweight, cesarean delivery, gestational diabetes mellitus, or maternal or infant length of stay after delivery. Comparing our outcomes to 4 other studies of contemporary PGT practice of frozen-thawed embryo transfers (Zhang WY Fertil Steril 2019, Li M Am J Obstet Gynecol 2020, Makhijani R Hum Reprod 2021, He H Fertil Steril 2019), our data are consistent with no effect of biopsy on low birth weight, pregnancy-induced hypertension, gestational diabetes, placenta previa, and placenta accreta. A slight decrease in preterm delivery (RR 1.10, CI 1.02-1.18), slight reduction in cesarean section (RR 0.90, CI 0.82-0.99), and increase in intrauterine growth restriction (RR 1.21, CI 1.06-1.38) are reported with biopsy in a systematic review (Hou W, Fertil Steril 2021). The increase in risk for intrauterine growth restriction with biopsy was influenced by one study (Li M Am J Obstet Gynecol 2020).

Conclusion
Embryo biopsy of trophectoderm cells for PGT in contemporary practice appears to be safe generally with respect to maternal and neonatal outcomes. There is no clear increase in diagnoses related to placentation (preeclampsia, pregnancy-induced hypertension, placental disorders, preterm birth, low birthweight), cesarean delivery, gestational diabetes mellitus, or maternal or infant length of stay after delivery. Further study of a possible increase in intrauterine growth restriction with biopsy is indicated.