3.1 Main findings
Meta-analysis showed that auricular acupressure was more effective for latent analgesia in the first stage of labour, but not in the active stage, which may be related to different severity of pain in the active and latent stages of labour. However, the incidence of grade III pain throughout labour was reduced in the auricular acupressure group, suggesting that auricular acupressure is effective in relieving breakthrough pain in labour. Since breakthrough pain after receiving pain relief can increase patient’s dissatisfaction[27],the maternal satisfaction shown in the meta-analysis was improved.
For the duration of labour, the first stage of labour was shorter in the auricular acupressure group, whereas the second and third stages of labour were not significantly different, which may be associated with the longer duration of the first stage of labour.
The safety of auricular acupressure is investigated through Apgar score, delivery mode and postpartum hemorrhage. These outcomes did not show any significant difference between auricular acupressure groups and the controls.
3.2 Limitations
First, only published Chinese and English articles were retrieved, which may lead to publication bias due to incomplete literature collection. Second, most included studies did not provide methodological details on randomization, allocation concealment and blinding, which reduced the reliability of the findings. Besides, although only one study used auricular acupuncture, the stimulation of auricular acupressure and auricular acupuncture is different, and the intensity of stimulation may vary between studies due to the degree or frequency of pressure. The significant heterogeneity of some outcomes may be attributable to this. In addition, although labour pain is different between nulliparous and multiparous women, the size of the fetus can also affect labour pain, some studies failed to specify these factors.
3.3 Implication for clinical trial design
As a subjective feeling, labour pain is highly complex, further well-designed trials with high methodological quality should be conducted, and careful trained clinicians and standardized intervention protocols are needed to minimize the subjective effect. Besides, to explore the differential analgesic effects among nulliparous and multiparous women and the effect of fetus size on labour analgesia, further studies as well as the manipulate methods (e.g. acupressure and acupuncture) are needed.