Aromatherapy, the therapeutic use of essential oils, is often used to reduce pain in primary dysmenorrhea. Eleven databases, including four English (PubMed, AMED, EMBASE, and the Cochrane Library) and seven Korean medical databases, were searched from inception through August 2018 without restrictions on publication language. Randomized controlled trials (RCTs) testing aromatherapy for pain reduction in primary dysmenorrhea were considered. Data extraction and risk-of-bias assessments were performed by two independent reviewers. All of the trials reported superior effects of aromatherapy for pain reduction compared to placebo (n = 1787, standard mean difference (SMD): -0.91, 95% CI: -1.17 to -0.64, p < 0.00001) with high heterogeneity (I² = 88%). A sub-analysis for inhalational aromatherapy for the alleviation of pain also showed superior effects compared to placebo (n = 704, SMD: -1.02, 95% CI: -1.59 to -0.44, p = 0.0001, I² = 95%). With regard to aromatherapy massage, the pooled results of 11 studies showed favorable effects of aromatherapy massage on pain reduction compared to placebo aromatherapy massage (n = 793, SMD: -0.87, 95% CI: -1.14 to -0.60, p < 0.00001, I² = 70%). Oral aromatherapy had superior effects compared to placebo (n = 290, SMD: -0.61, 95% CI: -0.91 to -0.30, p < 0.0001, I² = 0%). In conclusion, our systemic review provides a moderate level of evidence on the superiority of aromatherapy (inhalational, massage, or oral use) for pain reduction over placebo in primary dysmenorrhea.
Keywords: aromatherapy; dysmenorrhea; essential oil; inhalation; meta-analysis; pain; systematic review.