Table 1 Primary and secondary outcome measures of this RCT

Primary outcome

Live birth

Birth of a breathing live-born infant with a heartbeat after 28 completed weeks of gestation

Secondary outcomes

Clinical pregnancy

Presence of intrauterine gestation sacs at 30–35 days after embryo transfer

Ongoing pregnancy

Presence of a fetal pole with pulsation at 8–10 weeks of gestation

Early miscarriage

Miscarriage within 12 weeks of embryo transfer

Late miscarriage

Miscarriage between 12 and 28 weeks of embryo transfer

Cumulative live birth rate

Birth of a live-born infant conceived within three embryo transfers. Each time a single embryo is transferred is considered.

Ectopic pregnancy

Pregnancy outside the uterine cavity

Time to pregnancy

Time interval between the oocyte retrieval date and clinical pregnancy