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

Objective: Women 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. Methods: A 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. Results: A 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. Conclusion: Salbutamol + 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.