title: [Modern obstetrical anesthesia. Current status in the United States: 1].
mesh_terms: D000767:Anesthesia, Epidural; D000773:Anesthesia, Obstetrical / Q000639:trends*; D004723:Endorphins / Q000097:blood; D005260:Female; D006801:Humans; D009321:Natural Childbirth / Q000639:trends; D011247:Pregnancy; D014481:United States; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D001615:beta-Endorphin