Single Step Protocol and Multi-step Warming Protocol for Blastocyst FET

Live birth is defined as the complete expulsion or extraction from a woman of a product of fertilization, after 22 completed weeks of gestational age; which, after such separation, breathes or shows any other evidence of life, such as heart beat, umbilical cord pulsation or definite movement of voluntary muscles, irrespective of whether the umbilical cord has been cut or the placenta is attached. A birth weight of 500 grams or more can be used if gestational age is unknown

The survival rate by the presence of blastocoel re-expansion before embryo transfer.

Cancellation due to: The blastocyst cells are lysed after thawing.

Serum ß-hCG ≥25mIU/mL

The implantation rate is explained as the number of gestational sacs per number of embryos transferred

diagnosed by ultrasonographic visualization of one or more gestational sacs or definitive clinical signs of pregnancy at 6 weeks or more after the onset of the last menstrual period. In addition to intra-uterine pregnancy, it includes a clinically documented ectopic pregnancy.

A pregnancy outside the uterine cavity, diagnosed by ultrasound, surgical visualisation, or histopathology

Having at least one gestational sac on ultrasound at 12 weeks' gestation with heart beat activity

The spontaneous loss of an intra-uterine pregnancy before 22 completed weeks of gestational age

Multiple definitions, defined as delivery at <24, <28, <32, <37 completed weeks

Structural or functional disorders that occur during intra-uterine life and can be identified prenatally, at birth or later in life. Congenital anomalies can be caused by single gene defects, chromosomal disorders, multifactorial inheritance, environmental teratogens and micronutrient deficiencies. The time of identification should be reported. Any congenital anomaly will be included as followed definition of congenital abnormalities in Surveillance of Congenital Anomalies by Division of Birth Defects and Developmental Disabilities, NCBDDD, Centers for Disease Control and Prevention (2020).

Weight of singletons and twins

Weight < 2500 gm at birth

Weight < 1500 gm at birth

Weight over than 4.500 g for women with diabetes, and a threshold of 5.000 g for women without diabetes

The admittance of the newborn to NICU

≥2 gestational sac at early pregnancy ultrasound

Birth of more than one baby beyond 22 weeks

The death of a fetus prior to the complete expulsion or extraction from its mother after 20 completed weeks of gestational age. The death is determined by the fact that, after such separation, the fetus does not breathe or show any other evidence of life, such as heartbeat, umbilical cord pulsation, or definite movement of voluntary muscles.

Death of a live-born baby within 28 days of birth. This can be divided into early neonatal mortality, if death occurs in the first seven days after birth, and late neonatal if death occurs between eight and 28 days after delivery

Total direct cost to have a live birth after embryo transfer. Direct cost include medical consultations, ovulation stimulation drugs, laboratory and embryology services, ultrasound scanning, medical procedures such as oocyte retrieval and embryo transfer, hospital charges, nursing and counselling services and administrative and overhead charges. Cost data will be collected for a supplementary analysis and will be reported in a separated paper.