RT Journal Article SR Electronic T1 Epidural gravity flow technique for labor analgesia JF Regional Anesthesia & Pain Medicine JO Reg Anesth Pain Med FD BMJ Publishing Group Ltd SP 686 OP 687 DO 10.1136/rapm-2019-101192 VO 45 IS 9 A1 Gilbert J Grant A1 Ghislaine C Echevarria A1 Andrew P Agoliati A1 Jerome Lax A1 Shaul Cohen YR 2020 UL http://rapm.bmj.com/content/45/9/686.abstract AB