Outcome measures
OHSS
MISCARRIAGE, SECONDARY, MISCARRIAGE
The primary outcome was LBR. The secondary outcomes included quality of retrieved oocytes and obtained embryos, fertilization, implantation, clinical pregnancy, miscarriage and OHSS rates. Quality of retrieved oocytes was defined as the total number of Metaphase II (MII) oocytes which reported by the embryologist. Quality of obtained obtaining embryos was assessed based on: (1) the number of cells at Day 2 or Day 3, (2) the amount of fragmentation, (3) the variation in cell size and overall symmetry (perfect, moderately asymmetric, and severely asymmetric in size and shape of the cells), and (4) multinucleation. Fertilization rate was defined as the ratio of 2 pronuclear (2PN) to the total number of inseminated oocytes. Implantation rate was calculated with the number of observed gestational sacs divided by the number of embryos transferred for each patient. Clinical pregnancy was defined as the presence of a gestational sac on ultrasound. Miscarriage was defined as the spontaneous loss of a clinical pregnancy up to 20 weeks of gestation. Live birth referred to the birth of a live fetus after 24 weeks of gestation.