A Cohort Comparison Study on Women in Threatened Preterm Labor Given Nifedipine or Nifedipine and Salbutamol Tocolysis in Air Medical Retrieval

Abstract

ObjectiveWomen with threatened preterm labor in remote Australia often require tocolysis in the prevention of in-flight birth during air medical retrieval. However, debate exists over the tocolytic choice. MethodsA retrospective analysis was undertaken on data containing women who required air medical retrieval for threatened preterm labor within Western Australia between the years 2013 and 2018. ResultsA total number of 236 air medical retrievals were deemed suitable for inclusion; 141 received nifedipine, and 95 women received salbutamol + nifedipine. Tocolytic efficaciousness was reported in 151 cases, proportionally more (P < .05) from the women who received salbutamol + nifedipine (n = 68, 71.6%) compared with the women who received nifedipine only (n = 83, 58.9%). Those receiving salbutamol + nifedipine were more likely to suffer maternal tachycardia (n = 87 [91.6%] vs. n = 62 [44.0%]), fetal tachycardia (n = 26 [27.4%] vs. n = 13 [9.2%]), nausea (n = 17 [17.9] vs. n = 5 [3.55%]), and vomiting (n = 12 [12.6%] vs. n = 2 [1.4%]). Three women who received salbutamol + nifedipine had serious side effects including echocardiographic changes, chest pain, and metabolic and lactic acidosis. ConclusionSalbutamol + nifedipine tocolysis was proven to be more effective than nifedipine only. Although salbutamol + nifedipine had increased temporary side effects, most were nonsevere and managed in-flight.