Introduction
Aromatherapy was used as an intervention to treat nausea and/or vomiting in two pilot RCTs.76,97 Heterogeneity was observed in relation to the clinical setting and patient populations in which the studies were conducted, as well as the interventions, comparators and outcomes reported in each trial. As previously described (see Chapter 3, Meta-analysis of included randomised controlled trials) given these, we did not attempt to perform meta-analyses, and have thus reported a narrative summary only for each intervention and comparator set.
One trial compared aromatherapy with placebo in pre-natal wards97 whereas the other trial compared aromatherapy with routine antenatal care.76 Both trials were at unclear risk of bias: mainly due to poor reporting in the trial of Pasha and colleagues;97 and for uncertainty surrounding whether the trial was truly randomised or was a quasi-RCT in Ghani and Ibrahim.76 The women were described as experiencing symptoms at the mild to moderate end of the severity spectrum at baseline in both trials ().
Results for aromatherapy interventions for NVP
Aromatherapy versus no aromatherapy
One trial97 compared mint oil aromatherapy against placebo for the treatment of mild NVP.97 Another trial compared mixed essential oils (lavender and peppermint) and routine antenatal care, where no treatment oils were given, in women with mild to moderate nausea and/or vomiting (i.e. requiring antiemetics but not hospitalisation).
Rhodes Index of Nausea, Vomiting and Retching
In the trial of Ghani and Ibrahim,76 the observed difference in the overall change from baseline RINVR score in the aromatherapy group was reduced to 17.60 (SD 6.08) from 23.06 (SD 6.37) at the end of the 3-day trial (p < 0.001). The change score in the no aromatherapy control group was not reported so it is unclear if the aromatherapy was effective in reducing nausea and vomiting or if it was due to the time lag.
Nausea outcomes
Pasha and colleagues97 examined the effectiveness of mint aromatherapy on pregnancy-induced nausea intensity using a VAS. There was no significant difference between the two groups. However, the authors reported a trend towards improvement by day 4 in the mint group, where the score had reduced to 3.50 (SD 1.95) from 4.78 (SD 1.62) at baseline, and an increase in nausea score at the end of day 4 from baseline score in the placebo group [mean 4.38 (SD 2.18) at day 4 compared with mean 3.00 (SD 2.19) at baseline].
Vomiting outcomes
The trial of Pasha and colleagues97 also examined the effect of mint aromatherapy on the number of vomiting episodes.97 There was no significant difference between the two groups. However, there was a reported trend towards improvement by day 4 in the mint group where the mean number of episodes had reduced to 2.23 (SD 1.88) from 4.85 (SD 1.82) at baseline. In the placebo group there was no significant difference between the number of vomiting episodes at the end of day 4 and baseline [mean 2.55 (SD 2.55) at day 4 compared with mean 2.52 (SD 2.4) at baseline].
Retching outcomes
No independent retching outcomes reported.
Safety outcomes
No pregnancy outcomes or adverse events were reported in either of the included trials. There were no relevant data on this intervention from the UKTIS.
Summary
The evidence from the two trials
76,97 available for aromatherapy was predominantly at an unclear risk of bias.
The identified studies reported evidence of an improvement in symptoms over time, but there was no evidence of a difference compared with placebo or routine antenatal care.
Overall, few data are available with no evidence of an effect.
More larger, better-quality studies are required for to make any conclusions about this intervention.
