Table 2.

Secondary outcomes and related definition

Secondary outcomes	Definition
Clinical and laboratory outcomes
Total amount of FSH	Total amount of FSH used for ovarian stimulation
Number of follicles >  12 mm	The number of follicles > 12 mm measured by transvaginal ultrasound on the day of the trigger or the day before
Number of oocytes obtained	Number of oocytes obtained during oocyte retrieval
Number of embryos obtained	Number and quality of embryos obtained
Proportion of good-quality embryos	Embryos with 4 cells and < 25% fragmentation on day 2 or with ≥6 cells and ≤ 10% fragmentation on day 3, the proportion of oocytes resulting in top quality day 2 (or day 3) embryos according to validated morphological criteria
Oocyte fertilisation rate	The number of zygotes with 2PN over the number of mature oocytes for ICSI or over the number of oocytes for conventional insemination
Endometrial thickness	Endometrial thickness measured by transvaginal ultrasound on the day of the trigger or the day before
Serum E2 level	Serum E2 level on the day of the trigger or the day before
Serum P level	Serum P level on the day of the trigger or the day before
Serum testosterone level	Serum testosterone level on the day of the trigger or the day before
Follicular fluid E2 level	E2 level in the follicular fluid
Follicular fluid testosterone level	Testosterone level in the follicular fluid
Follicular fluid inhibin B level	Inhibin B level in the follicular fluid
Follicular fluid AMH level	AMH level in the follicular fluid
Pregnancy outcomes
Miscarriage	Spontaneous loss of an intrauterine pregnancy before 20 completed weeks of gestational age
Clinical pregnancy	Presence of one or more intrauterine gestational sacs at 6 weeks of gestation
Ongoing pregnancy	Presence of one or more gestational sacs and foetal heartbeat after 12 weeks of gestation
Maternal safety outcomes
OHSS	It is classified as mild, moderate or severe according to the degree of abdominal distention, ovarian enlargement and respiratory haemodynamic, and metabolic complications. Diagnosed by ultrasound, blood testing and physical examination according to the RCOG Guideline
Ectopic pregnancy	A pregnancy outside the uterine cavity, diagnosed by ultrasound, surgical visualisation or histopathology
Obstetric and perinatal complications
Hypertensive disorders of pregnancy	Including pregnancy-induced hypertension, preeclampsia and eclampsia
Antepartum haemorrhage	Including placenta previa, placenta accreta and unexplained
Multiple pregnancies	Pregnancy with more than one foetus
Birth weight	Including low birth weight (weight <  2500 g at birth), very low birth weight (<  1500 g at birth), high birth weight (> 4000 g at birth) and very high birth weight (> 4500 g at birth)
Small for gestational age	Birth weight less than the 10th centile for the sex-specific birth weight for a given gestational age reference
Preterm delivery	Birth of a foetus delivered after 28 and before 37 completed weeks of gestational age
Congenital anomaly	Structural or functional disorders that occur during intrauterine life and can be identified prenatally, at birth or later in life, including trisomy 21 syndrome, neural tube defect, congenital heart disease, cleft lip, excessive numbers of fingers or toes and hydrocephalus
Perinatal mortality	Foetal or neonatal death occurring during late pregnancy (at 28 completed weeks of gestational age and later), during childbirth, or up to seven completed days after birth