A comparison of pain levels following injections of hypotonic saline, sterile water or normal saline: A randomised trial

INTERVENTION: Intervention group 1: Participants in this group will receive two simultaneous injections of 0.2% sodium chloride solution into the intradermal layer of the skin above the posterior superior iliac spines (PSIS). The injections will done by two registered midwives trained in the procedure. The injections take less than 30 seconds to complete and are given once. The 0.2% sodium chloride solution will be achieved by mixing 0.2mls of 0.9% sodium chloride for injection with 0.8mls of sterile water for injection. The volume injected at each site will be 0.1‐ 0.3mls depending on the visual assessment of the resulting bleb. Consistency in site selection and procedural continuity will be monitored by the administering investigators. Intervention group 2: Sterile water. Participants in this group will receive two simultaneous injections of sterile water into the intradermal layer of the skin above the PSIS. The volume injected at each site will be 0.1‐0.3 mls. CONDITION: Reproductive Health and Childbirth ‐ Childbirth and postnatal care sterile water injections for labour pain management ; ; sterile water injections for labour pain management PRIMARY OUTCOME: Determine the size of the difference between intervention and control groups in the self‐reported (visual analogue) injection pain score[Self reported pain using ungraded 100mm VAS At time of injections ] SECONDARY OUTCOME: Changes in systemic reaction following injections [Self reported questionnaire designed specifically for the study At 1 minute post injections ] Changes in systemic reaction following injections [self reported questionnaire designed specifically for the study At 10 minutes post injection ] Changes in systemic reaction following injections [self reported questionnaire designed specifically for the study At 60 minutes post injection ] Difference in injection pain [self reported pain using VAS At 10 minutes post injection] Difference in injection pain [Self reported pain using VAS At 30 seconds post injections] Difference in injection pain [self reported pain using VAS At 5 minutes post injection ] Difference in injection pain [Self reported using VAS 15 minutes post injection ] Difference in injection pain [Self reported using VAS At 2 minutes post injection ] Difference in injection pain[Self reported using VAS At 1 minute post injection] INCLUSION CRITERIA: Student enrolled at the University of Queensland Substantially healthy (self assessed) Aged between 18 – 45 years Female se X(at birth)