PRL and polycystic ovary syndrome: Compared to the Control group, the PCOS group exhibited decreased levels of ER, PR, and PRL, indicating incomplete decidualization(Fig. 4C and D, MD of ER, PR, and PRL = 400.1, 334.2, 454.9, p = 0.0043, p = 0.0025, p = 0.0077; Fig. 4Eand Supplementary Fig. 5,MD of ER, PR, and PRL = 0.6140, 0.4345, 0.4203, p < 0.0001, p = 0.0032, p = 0.0009).