Outcome measures
According to ASRM consensus and ACOG, the definition of clinical
outcomes was confirmed9,10. Our main outcome was live
birth while miscarriage rate, clinical pregnancy rate, preterm birth
rate, and ectopic pregnancy rate were secondary outcomes. Live birth was
defined as the delivery of at least one live-born baby beyond 22 weeks
of gestation. Live birth rate was defined as live deliveries (at least
one live birth) per woman after embryo transfer. Miscarriage rate was
defined as the spontaneous loss of a clinical pregnancy before 22
completed weeks of gestational age
per clinical pregnancy cycle.
Clinical pregnancy was defined as a pregnancy diagnosed by
ultrasonographic visualization of one or more gestational sacs or
definitive clinical signs of pregnancy. Preterm birth was defined as a
birth that takes place after 22 weeks and before 37 completed weeks of
gestational age. Ectopic pregnancy was defined as gestational sac
observed by ultrasound outside the uterine cavity. Implantation rate was
defined as the number of gestational sacs observed divided by the number
of embryos transferred.