The equation describing the probability of OHSS was as follows: P= −3.47315 to 0.05521 × FSH+0.24700 × AMH+0.00014 × total dosage of Gn used +0.00015 × E2 value on the day of hCG injection +0.07249 × follicle number on the day of hCG injection. This evidence concerns the gene BRD2 and ovarian hyperstimulation syndrome.