Table 3: Description of the interventions and protocols used in the selected studies.

ReferenceIntervention and protocol
Comparison group ()Treatment group(s) ()Type of essential oil usedDuration of the studyAdministration methodTreatment frequencyDuration per sessionTotal number of sessions

Inhalation aromatherapy

[18]Control with sweet almond cold-pressed pure vegetable oil with no fragrance (NA)(i) Carrier oil with fractionated low (NA) grade essential oil
(ii) Pure essential oil (NA)
(i) Fractionated oils of unknown purity diluted 1 : 3 in carrier oil
(ii) Mixture of lavender, bergamot, and cedarwood (2 : 1 : 1)
8 weeks3 drops of oil applied to a bib worn during the administration of the treatmentDaily15–20 min56

[19]Control, jojoba oil (14)(i) 2% dilution of a mixture of essential oils (6)(i) 0.25 rose otto essential oil and 0.75 lavender, 2% dilution of the essential oil mixture4 weeks8 drops of oil applied to a cotton pad. Subjects were instructed to smell the cotton pad for 15 minTwice a week15 min8

[20]Control, no intervention (6)(i) Pure essential oil (7)(i) Lavender
(ii) Petitgrain
(iii) Bergamot
1 day5 drops of oil applied on a filter placed in a diffuserOnce5 min1

[21]Control, water (20)(i) Pure essential oil (20)(i) Yuzu2 days10 L oil in a cotton pad used in a diffuser set in the subject’s nostrilsTwice10 min (sessions separated in intervals around 2.6 days)2

[22]Control group which did not receive any nonpharmacological method for pain relief of labor (160)(i) Nonpharmacological methods for pain relief of labor including showering, being in upright position, aromatherapy, and soft music without words (160)(i) 20% lavender essential oilDuring labor10 × 10 cm cloth impregnated with 1 mL 20% lavender essential oil which was attached to the mother’s breast at the beginning of the active phase. The aromatherapy intervention was combined with other nonpharmacological interventionsOnceDuration of the active phase of labor1

Aromatherapy massage

[23]Control, grape seed oil (16)(i) Diluted essential oil (16)(i) 9 essential oils (bergamot, lemon clary sage, lavender, roman chamomile, geranium, rose otto, sandalwood, and jasmine). A combination of essential oils chosen by the aromatherapist on each treatment session (16)12 weeks15 mL grape seed carrier oil with (4 drops) or without essential oils applied in a full body massage using gentle effleurage and petrissageOnce a fortnight40 min6

[24]Control, no intervention (13)(i) Aromatherapy massage (16)
(ii) Massage with inert carrier oil (13)
(i) 1% lavender essential oil diluted in sweet almond oil2 yearsBack massageWeekly30 min4

[25]Usual supportive care(i) Usual supportive care and aromatherapy massage(i) 20 essential oils10 weeksStandardized massage agreed by the therapistsWeekly1 h4

[26]Control, no intervention(i) Aromatherapy massage(i) 1% massage oil containing melissa, juniper, and rosemary essential oils mixed into jojoba oil (1 : 2 : 2 ratio)8 weeksStandardized massage on the back, shoulders, arms, hands, lower legs, and feet using 20–30 mL massage oilEvery two weeks1 h4

[19]Control, essential oil blend unscented white lotion (14)(i) 2% dilution of a mixture of essential oils (8)(i) 0.25 rose otto essential oil and 0.75 lavender, 2% dilution of the essential oil mixture4 weeksTopic application of the oil or lotion on both hands with gentle strokes of homogeneous pressure and speedTwice a week15 min8

[27]Cognitive behavior therapy (19)(i) Aromatherapy massage (20)(i) 20 essential oils2 yearsStandardized massage combined with treatment as usual (routine support)Weekly1 hUp to 8 sessions in 10 weeks

[28]Control, no intervention (30)(i) Aromatherapy massage (30)
(ii) Massage (30)
(i) 3% oil mixture containing lavender, geranium, rose, and rosemary (4 : 2 : 1 : 1 ratio) in almond and evening primrose oil4 weeksMassage in the abdomen, tights, and arms using massage oil containing essential oils or odorless liquid petrolatum. Massage was applied with clockwise circular movements and light pressureTwice a week30 min8

[29]Control, no intervention (12)(i) Aromatherapy massage (13)(i) Jojoba oil containing 2% lavender and 2% geranium essential oils4 weeksMassage on the neck, shoulders, arms, back, and legs including effleurage, friction, petrissage, and vibration at a moderate pressure using 20 mL of massage oilTwice per week40 min8

In this study, both aromatherapy modalities were tested, inhalation aromatherapy and aromatherapy massage. Therefore, the study was included in both categories in the table. NA, not available; min, minutes; h, hour.