title: Early versus late epidural analgesia and the risk of instrumental delivery in nulliparous women.
authors: M C
authors: MC
authors: Klein
mesh_terms: D015360:Analgesia, Epidural / Q000009:adverse effects*; D016362:Analgesia, Obstetrical / Q000009:adverse effects*; D036861:Delivery, Obstetric / Q000295:instrumentation*; D005260:Female; D006801:Humans; D011247:Pregnancy