Inclusion Criteria:  Primiparae between 18 and 34 years of age with term single cephalic pregnancy; Undergo regular prenatal examination in the study centers; Preparing to deliver vaginally.  Exclusion Criteria:  History of psychiatric diseases (indicate those that are diagnosed before or during pregnancy by psychiatrists); History of diseases involving the hypothalamic-pituitary-adrenal axis; Presence of contraindications to epidural analgesia, which includes: (1) History of infectious disease of the central nervous system (poliomyelitis, cerebrospinal meningitis, encephalitis, etc.); (2) History of spinal or intra-spinal disease (trauma or surgery of spinal column, intra-spinal canal mass, etc.); (3) Systemic infection (sepsis); (4) Skin or soft tissue infection at the site of epidural puncture; (5) Coagulopathy. Presence of contraindications to vaginal delivery; Other reasons that are considered unsuitable for study participation.