Introduction: Anxiety is the most common psychological response to labor in women. Aromatherapy is a type of alternative medicine which by using es­sential oils and fragrant, stimulates the olfactory system, induces relaxation and reduces anxiety. This study aims to determine the effect of aromatherapy with Boswellia Carteri in reducing anxiety during the first stage of labor.

Methods: This randomized clinical trial was conducted on 126 nulliparous women, referred to Kamali hospital (Karaj, Iran). Samples were divided into two groups of aromatherapy and control. In intervention group, gauzes impregnated with 2 ml normal saline and 0.2 mL Boswellia essence, and in control group only with 2 ml normal saline were attached to the collar of subjects. Gauzes were changed every 30 minutes. Level of anxiety in both groups were measured at baseline and after the intervention at dilations of 3-4 and 6-8 cm. Data was collected using a demographic and obstetric information questionnaire, an observation-examination checklist, and Spielberger state-trait anxiety questionnaire.

Results: Before the intervention; gestational age, Bishop Score, contraction length and level of anxiety was the same in both groups. After the intervention, mean of anxiety in the intervention group at dilations of 3-4 (18.4±5.18) and 6-8 cm (20.3±6) was significantly lower than control group at dilations of 3-4 (22.3±7.98) and 6-8 cm (22.9±5.55), (P=0/014,P=0/002).

Conclusion: The results of this study confirmed aromatherapy with Boswellia Carteri essence as a simple, inexpensive, noninvasive, and effective intervention to reduce anxiety during labor.