PAPPA and polycystic ovary syndrome: To validate the microarray results, confirmatory qRT-PCR was performed for randomly selected 21 significantly differentially expressed genes (p-value < 0.01), namely FOXO1, FOXO3, FOXP1, GPC4, GPSM1, IL33, INSR, KLF2, MAN2B2, MYO10, NAGA, PAPPA, PCSK5, PHEX, PLD2, RABGAP1, SIN3A, SQSTM1, TCF7L2, USP9X, and ZFP36, in OHSS compared to PCOS group (Figure S1).