Maternal microcirculation and sidestream dark field imaging: A prospective assessment of the association between labour pain and analgesia on the microcirculation of pregnant women

BACKGROUND: Pregnancy places significant demands on the cardiovascular system leading to measurable changes in the macrocirculation and potentially the microcirculation. During labour, both uterine contractions and labour pain can further impact cardiovascular status. The objective of this observational study was to compare sublingual microcirculation in labouring parturients before and after epidural analgesia. METHODS: Healthy pregnant, labouring women requesting epidural analgesia were approached to participate. Participants with cardiovascular disease, diabetes, obesity, smoking or caffeine intake were excluded. The sidestream dark field device was applied to the sublingual mucosa obtaining images of at least 20 seconds in 5 visual fields before and after epidural analgesia. Video clips were analyzed randomly and blindly. The primary outcome was mean microvascular flow index (MFI). RESULTS: Twelve participants completed this study. The results demonstrate no statistically significant difference in the MFI during labour pain (2.9±0.1) compared to after epidural analgesia (3.0±0.04, p = 0.31). Furthermore, there were no statistically significant differences in any secondary outcomes. CONCLUSION: Our findings indicate that epidural analgesia may not impact sublingual microcirculation in labouring women. This agrees with literature supporting epidural analgesia as a safe, appropriate method of pain relief during labour with limited impact on peripheral macro or microcirculation.