NCT02570386

Trial name or title	Clinical effectiveness of frozen thawed embryo transfer compared to fresh embryo transfer
Methods	RCT Estimated enrolment: 800
Participants	Women aged 18 to 42 Inclusion criteria: Women under 42 years of age Presence of at least 3 embryos suitable to freeze on day 2 or 3 following fertilisation based on the centre's criteria Written informed consent Exclusion criteria: Women using donor eggs/donor sperm Women undergoing pre‐implantation genetic diagnosis Women with abnormal uterine cavity shown on hysterosalpingogram or saline infusion sonogram Women with hydrosalpinges shown on scanning and not treated Women with excessive ovarian response at risk of ovarian hyperstimulation where elective freeze is already planned Women with serum progesterone level on day of hCG > 1.5 ng/mL or 5 nmol/L Women whose embryos have previously not survived freeze‐thawing Fresh transfer is planned, e.g. women with endometriosis or adenomyosis who have received prolonged down‐regulation Only frozen transfer is planned, e.g. women receiving ovarian stimulation regimens that may adversely impact the endometrium
Interventions	Intervention: Fresh embryo transfer will not be undertaken in this group. Embryos will be frozen by vitrification or slow freezing at cleavage or blastocyst stage according to standard agreed local protocols. Women will be contacted after 4 weeks and arrangements made for frozen embryo transfer. Control: Women allocated to the control arm will either undergo fresh embryo transfer at cleavage stage or extended culture and transfer at blastocyst stage according to local policy. A maximum of 2 embryos or blastocysts will be replaced according to the standard protocol under transabdominal ultrasound guidance. Luteal‐phase support is given according to local protocols.
Outcomes	Cumulative live birth: within 6 months of ovarian stimulation from the fresh and frozen‐thawed embryo transfer Live birth: a baby born alive after 20 weeks' gestation Miscarriage: miscarriage before 20 weeks' gestation Clinical pregnancy: presence of at least 1 gestational sac on ultrasound at 6 weeks Ovarian hyperstimulation: classified according to Royal College of Obstetrics and Gynaecology in the United Kingdom Complications of pregnancy
Starting date	October 2015
Contact information	Ernest HY Ng: nghye@hku.hk
Notes	clinicaltrials.gov/ct2/show/record/NCT02570386