IVF procedure
All the patients received a standardized ovarian stimulation regimen in
the PGT-A cycles according to their ovarian function. In brief,
recombinant FSH was used for ovarian stimulation in
gonadotropin-releasing hormone agonist, gonadotropin-releasing hormone
antagonist protocols or others. Oocyte retrieval was performed 36 h
after triggering with hCG.
Insemination of retrieved oocytes was done by intracytoplasmic sperm
injection (ICSI). Laser-assisted breaching of the zona pellucida was
performed on day 3. The embryos were assessed on day 5 and 6, and
trophectoderm (TE) biopsy was performed. Biopsied TE cells were then
stored at -20℃ for future whole genome amplification (WGA) and next
generation sequencing (NGS). After the biopsy, blastocysts were
vitrified to be replaced in the subsequent frozen-thawed embryo transfer
cycle.
Only cycles where at least one euploid blastocyst was available for
transfer were included in this study. In ovulatory patients, embryo
transfers were timed after ultrasound confirming ovulation. Anovulatory
women were managed with an artificial hormone replacement regime.
Pregnancy was confirmed by serum β-hCG assessment 14 days after embryo
transfer.