Treatment
All patients received a standard ovarian stimulation protocol
(antagonist or long protocols),
oocyte retrieval, fertilisation, embryo cultured and cryopreservedin vitro , and a luteal phase support protocol after embryo
transfer (ET), according to a routine method. All patients who underwent
FET in this study were found unsuitable for undergoing a fresh embryo
transfer or did
not
get a viable neonate after undergoing a fresh embryo transfer. The
outpatient physician chose the most appropriate protocol based on
clinical indications of the prepared endometrium, which mainly included
a natural cycle, hormonal replacement therapy cycle and ovulation
induction cycle. Frozen blastocysts were thawed and transferred, and
subsequently provided with luteal phase support according to different
endometrial preparation programs.