Aromatherapy Using Lavender Oil Effectiveness on Pain and Anxiety After C-Section: A Randomized Controlled Trial

Abstract

Background

Managing postoperative setting, regarding pain and anxiety after cesarean delivery is crucial for the mother’s recovery, her emotional well-being, mother-infant bonding and initiating breastfeeding. Although some research have suggested that aromatherapy with lavender essential oil can be effective in reducing pain and anxiety in various medical settings, the efficacy of lavender aromatherapy in the postoperative setting after cesarean delivery is less well-studied. We aimed to assess the effectiveness of lavender essential oil therapy in the management of pain and anxiety after cesarean delivery.

Methods

This was a monocentric randomized controlled double-blind trial conducted over a period of five months during 2023. A hundred women undergoing c-sections under spinal anesthesia were enrolled and randomly assigned; using block randomization of 4 items per block with allocation ratio 1:1, into two groups: The aromatherapy group (receiving inhaled Lavender essential oil) versus the placebo group (receiving distilled water instead). The primary outcomes were pain (at rest and after mobilization) and anxiety levels and after the intervention. This trial was registered on clinical-trials.org (NCT06387849).

Results

A total of 100 women were included (50 women in each group aromatherapy and the placebo group). The two groups were comparable regarding baseline characteristics and pre-intervention parameters with no statistically significant difference. After the intervention, the pain at rest (38,76 ± 22,9 vs. 23,84 ± 18,01; p < 0.001), the pain after mobilization (60,28 ± 23,72 vs. 40,12 ± 22,18; p < 0.001), and degree of anxiety (46,76 ± 6,59 vs. 44,3 ± 5,17; p = 0.03) were all significantly lower in the aromatherapy group. No adverse effects were reported by participants in both groups.

Conclusion

Aromatherapy using Lavender essential oil is effective in reducing pain and anxiety after cesarean delivery without adverse effects.

Supplementary Information

The online version contains supplementary material available at 10.1007/s44197-024-00305-6.

Introduction

The International Association for the Study of Pain (IASP) defines pain as “a covert feeling and an emotional experience associated with acute or potential tissue damage” [1]. This definition describes pain as a biopsychological experience and a manifestation of tissue damage, such as surgery [1]. Besides, anxiety is defined as an emotional state anticipating a threatening event and is characterized by distressing feelings of fear, alertness, hypervigilance, apprehension, and dread of imminent danger, associated with neurovegetative manifestations [1]. Preoperative anxiety is experienced by 60–92% of patients undergoing anesthesia and surgery [2]. Human adaptability is reduced and fear of uncontrollable pain increases, which in turn increases the sensation of pain, creating a vicious cycle [3]. Prolonged or uncontrolled anxiety can lead to altered immune responses, fluid and electrolyte imbalances, and changes in sleep patterns, which can lead to longer hospital stays and delayed discharge [4]. This anxiety can even lead to lactation failure in new mothers [5]. Moreover, caesarean section is the most commonly performed surgical procedure for women worldwide [6]. Although the circumstances of cesarean delivery in almost all cases should give rise to joy, it is also a dreaded event associated with significant levels of pain and anxiety [7].

Managing postoperative setting, regarding pain and anxiety after cesarean delivery is crucial for the mother’s recovery, her emotional well-being, early mother-infant bonding and initiating breastfeeding. These specific challenges associated with cesarean delivery emphasizes the potential for non-pharmacological interventions to improve outcomes in a vulnerable population facing significant physical and emotional hurdles.

Given their non-invasive nature, safety, and acceptability to the general population, complementary and herbal therapies, including aromatherapy with lavender essential oil (EO), have gained in popularity and experienced rapid growth [8]. Lavender is a medicinal plant native to the Mediterranean and found also in Africa and India [9]. The lavender essential oil has many benefits, including relief of pain and discomfort, relaxation, and a sense of well-being [9]. Lavender’s spasmolytic, relaxing, and soothing effects result from its components, which, even when inhaled, increase blood circulation and reduce muscle tone [10]. Lavender aromatherapy has been shown to significantly reduce anxiety levels in various medical contexts. For instance, a study involving patients undergoing spinal procedures found that those exposed to lavender aromatherapy had lower anxiety scores compared to a control group, indicating its effectiveness as a non-sedating anxiolytic agent [11]. Another study demonstrated similar findings in preoperative settings, where lavender significantly decreased anxiety and the required dosage of sedatives like propofol [12]. Lavender has also been reported to alleviate pain. Research involving dental procedures indicated that lavender aromatherapy effectively reduced pain perception during injections in children [13]. In the obstetrical setting, some previous studies highlighted its role in managing and reducing labor pain [14, 15]. These findings are significant in demonstrating that lavender aromatherapy can effectively manage labor pain, and they provide a foundation for further exploration of its potential benefits in the postpartum period, including post-cesarean recovery. However, while these studies emphasize labor pain management, there is still a lack of focused research specifically examining lavender’s effects on postoperative pain and anxiety following cesarean delivery, underscoring the need for targeted studies in this area.

In Tunisia, there is a dearth of comprehensive data concerning pain and anxiety management following cesarean deliveries. This gap is particularly significant regarding the use of aromatherapy, which has not been extensively studied in this context. This study aims to assess the effectiveness of lavender EO therapy in the management of pain and anxiety after cesarean section delivery as a non-invasive, low-risk, and potentially cost-effective intervention to enhance maternal comfort and well-being post-C-section. This focus is crucial as it may offer new insights into integrative pain and anxiety management strategies, especially in low- and middle-income countries like Tunisia.

Methods

Trial Design

This was a monocentric randomized controlled double-blind clinical trial with a two-arm parallel design. It was conducted during a period of five months in Ben Arous Regional Hospital obstetrics and gynecology department in Tunisia between April and August 2023.

Recruitment and Eligibility Criteria

The Inclusion Criteria were as Follow

All women who underwent a cesarean section under spinal anesthesia and were aged between 18 and 45 years old, with at least a primary education level, classified ASA 1 or 2 of the American Society of Anesthesiology (ASA) classification, with no history of cancer or chronic pain nor psychiatric disorders and no per-partum adverse events.

The Exclusion Criteria were as Follow

All women who received pain killers before the intervention, suffered from addiction or olfactory disorders or allergy to aromatic plants, were excluded from this trial.

Comparison Groups

The participants were randomized into two groups:

• Experimental group: Aromatherapy group.

• Control group: Placebo group.

Intervention and Outcomes

The lavender essential oil (EO) was extracted by the hydro distillation method using a Clevenger-type apparatus [16]. The recovered EO was dried with anhydrous sodium sulfate and stored in a hermetically sealed opaque glass bottle in a refrigerator at around 4 °C, to protect it from air, light, and temperature variations [16]. During transport to the clinical trial site, the EO was stored in an isothermal bag with a cold accumulator (protected from heat, light, and air).

Between 2 and 12 h after the Caesarean section, women in the experimental group (aromatherapy group) received aromatherapy using lavender essential oil. Patients were asked to inhale a cotton ball soaked in 3 drops of the essential oil from a distance of 10 centimeters during 30 min [3]. The same procedure was carried out for the placebo group, with the administration of 3 drops of distilled water instead of lavender oil.

Baseline data regarding demographic information (age, education, employment) and medical history were gathered before entering surgery. After surgery, baseline pain level was measured using the Visual Analogue Scale (VAS) on a scale of 0-100 by a ruler. The Arabic version of the Spielberger State-Trait Anxiety Inventory (STAI- Y2) was used to evaluate the baseline covert anxiety (STAI- Y2) and the overt anxiety (STAI- Y1) of enrolled women [17]. The Overt anxiety scale consists of 20 items that assess an individual’s immediate emotions at the time of reaction. The Covert Anxiety Scale has the same number of items assessing general anxiety emotions [3]. Five minutes after the procedure ended, we evaluated the VAS and the overt anxiety (STAI- Y1). We also recorded eventual adverse outcomes during and after the intervention and the need for painkiller medication adjunction in both groups. The participants in the study were closely monitored by the investigator to record any events, including but not limited to changes in respiratory or cardiac status, headaches, or itching/watering of the eyes that may indicate an adverse effect of the essential oil. In the event of adverse effects related to inhalation, the procedure will be discontinued for the affected patients.

Both primary and secondary outcomes were measured 5 min after the end of the intervention.

• Primary outcomes: pain and overt anxiety levels measured by VAS, STAI- Y 1 respectively.

• Secondary outcomes: Heart Rate (HR) (ppm), Systolic Blood Pressure (SBP) (mmHg), Diastolic Blood Pressure (DBP) (mmHg), Respiratory Rate (RR) (cpm) and Pulsatile Oxygen (SPO2) (%).

Sample Size Calculation

The sample size was calculated using G-power 3.1.9.7 [18], which is a is a statistical power analysis software, for independent t-test and considering alpha, power, the number of groups, and the effect size (representing the minimal clinically meaningful difference) based on Cohen’s suggestions [19]. The values used were an alpha error of 0.05 and 95% power, number of groups 2, and the effect size of 0.8 with equal group sizes (ratio 1:1). The minimal required number of patients was equal to 84 (42 in each group).

The formula used for sample size calculation was the following:

where:

• n = sample size per group.

• Z-score corresponding to the desired significance level (e.g., 1.96 for a two-tailed test at alpha = 0.05)

• -score corresponding to the desired power

• estimated variance of the outcome measure

• expected difference between group means (effect size)

Sampling Method and Randomization

A total of 100 patients divided equally into two groups of 50 patients each, were included. A computer-generated randomization sequence Random Allocation Software 1.0.0 (Freeware) was used for the randomization process [20]. The patients were block randomized with equal block sizes of 4 items per block (allocation ratio 1:1). A random selection of these combinations (25 combinations) was made until the desired size was reached, i.e. 50 patients in each group.

Blind Protocol Implementation

The principle of double blind was respected during all the trial phases.

The two products tested in this study, lavender EO and distilled water (placebo), were placed in identical opaque sealed vials that were indistinguishable from one another. The vials were labeled as A or B (as shown in accompanying image: Fig. 1) by laboratory personnel before being distributed to the clinical service administering the treatments. Both substances were colorless, ensuring that the placebo closely mimicked the lavender in all aspects except for its scent. Only the laboratory personnel were privy to the identities of A and B vials.

Fig. 1.

The A and B deidentified vials used in the experimentation

To address the potential for participants to differentiate between the lavender and the placebo based on olfactory cues, they were informed that they would receive a natural inhalation product; however, they were not informed that it was an essential oil or specifically lavender. This approach was crucial to prevent participants from anticipating a specific aroma, which could lead to bias in their perception of the treatment. The aim was to maintain patient blinding effectively, thereby minimizing any preconceived notions about the expected effects of the inhaled substance. To further ensure that participants remained unaware of their assigned treatment, they were placed in individual rooms, thereby eliminating any interaction with other participants that could lead to cross-contamination of information or influence each other’s experiences.

Moreover, to mitigate the risk of bias during outcome assessment, we assigned distinct responsibilities to different investigators. A caregiver nurse was responsible for administering the treatment to the patient with the assigned product and closely monitoring adherence to the inhalation protocol while providing assistance as needed. Training was provided to all caregivers involved in the administration of the intervention, focusing specifically on the techniques for product administration and inhalation. This training is crucial to ensure that caregivers are well-equipped with the necessary skills and knowledge to effectively deliver the intervention while adhering to safety and procedural guidelines. Meanwhile, a separate investigator—consistent across all participants—was designated to measure outcomes, to ensure better standardization of data collection and minimize information bias related to the investigator. This division of tasks was critical in preserving the blinding of both the participants and the investigators, thereby reducing potential biases in data collection.

Statistical Analysis

Data entry and analysis were performed using IBM^® SPSS^® statistics (version 21). Quantitative variables were expressed as mean ± standard deviation (SD). Qualitative variables were expressed as percentages. The comparison of baseline characteristics between the two groups was carried out using the Student-T-test for independent samples when comparing means, and Chi-square test or Fisher’s Exact Test when comparing percentages. The One-way analysis of variance (ANOVA) test was used to compare more than two means. The Student-T-test for independent samples was used to compare groups after intervention regarding the primary and secondary outcomes. A p value ≤ 0.05 was considered as significant for all tests.

Ethical Considerations

The study protocol was approved by the local Institutional Review Board (approval no. 03/2023). This trial was registered on clinical-trials.org (NCT06387849) on April 2024.

The informed written consent was taken from all included women before participating to the study and after explaining its purpose.

Results

Out of the 341 women assessed for eligibility, one hundred met our inclusion criteria and were accepted to be enrolled in our study. They were equally randomized in the two groups: The aromatherapy group (n = 50) and the placebo group (n = 50). All patients completed the intervention in both groups. The CONSORT 2010 flow diagram is detailed in Fig. 2.

Fig. 2.

CONSORT Flowchart

The mean age of women in the placebo group was 32,3 ± 4.5 years versus 31,3 ± 3.8 years in the aromatherapy group, with no statistically significant difference (p = 0.27). The results of the Mann-Whitney test showed that the two groups were homogeneous regarding all demographic features (p > 0.05) (Table 1).

Table 1.

Patients’ baseline demographic characteristics and high-risk pregnancy factors

	Placebo group (n = 50)	Aromatherapy group (n = 50)	p-value
Age(years) α	32,3 ± 4.5	31,3 ± 3.8	0.27a
Educational level, n (%)β  Primary and middle school  High school  Collage degree	5 (10) 27(54) 18(36)	5 (10) 29(58) 16(32)	0.85b
Geographic origin, n (%)β  Urban  Rural	7(14) 43(26)	9(18) 41(82)	0.29b
Smoking, n (%)β  Yes  No	5 (10) 45 (90)	3(6) 47(94)	0.72b
ASA γ, n (%)β  ASA1  ASA2	40(80) 10 (20)	42(82) 8 (16)	0.8b
History of surgery, n (%)β  Yes  No	32 (64) 18 (36)	30 (60) 20 (40)	0.6b
History of C-section delivery, n (%)β  Yes  No	22(44) 28 (56)	20 (40) 30 (60)	0.9b
High-risk pregnancy factors, n (%)β  Diabetes mellitus  Gestational hypertension  Severe anaemia	16 (32) 4 (16) 4 (16)	12(24) 0(0) 6(12)	0.37c
Term on delivery (days) α	272,38 ± 8,54	271,88 ± 7,63	0.79a
Type of C-section, n (%)β  Scheduled  Emergency	37 (74) 13 (26)	41(82) 9 (18)	0.7b

α: data presented as mean ± Standard deviation; β: data presented as number of events (n) and percentages (%); γ: ASA: Classification of the ’American society of Anaesthesiology; a: Student t-test; b: Chi-square test; c: Fisher’s Exact Test

The intervention was administrated 6.03 ± 2,12 h after C-section in the placebo group versus 6,82 ± 2,86 h in the aromatherapy group, with no statistically significant difference between the two groups (p = 0.12).

The comparison of the two groups showed that baseline parameters (VAS, STAI- Y2, STAI- Y1, HR, SBP, DBP, RR, and SPO2) measured before the intervention were not statistically different, suggesting the homogeneity of the two groups in pre-intervention regarding these parameters (Table 2).

Table 2.

Time of intervention and outcome parameters measured before the intervention

	Placebo group (n = 50)	Aromatherapy group (n = 50)	p-valuea
Time of intervention (hours) α	6.03 ± 2,12	6,82 ± 2,86	0.12
Systolic Blood Pressure (mmHg) α	116 ± 17,2	110,6 ± 15,5	0.1
Diastolic Blood Pressure (mmHg) α	65,6 ± 1,14	67,8 ± 11,6	0.34
Heart rate (ppm) α	88,92 ± 14,4	89,42 ± 15,12	0.87
Pulsatile Oxygen Saturation (%)α	96,8 ± 3,48	96,58 ± 2,4	0.72
Respiratory Rate (cpm)α	19,78 ± 3,98	19,76 ± 5,25	0.98
Visual Analogue Scale (at rest) α	38 ± 20,22	41,38 ± 22,36	0.42
Visual Analogue Scale (after mobilisation) α	62,32 ± 20,49	70,10 ± 20,19	0.056
Covert anxiety (STAI-Y2) α	44,06 ± 8,01	44,36 ± 10,35	0.87
Overt anxiety (STAI-Y1) α	46,22 ± 5,79	46,04 ± 5,76	0.88

α: data presented as mean ± Standard deviation; a: Student t-test

We analyzed the association between demographic features and pre-intervention pain and overt anxiety in the study population and in the two groups. Lower educational level was associated with higher pain levels (p = 0.045). This association was not found in the sub-group analysis. In addition, the mean pain severity in the Placebo group was lower in patients of rural origin than urban ones (25.4 ± 11.43 versus 40.0 ± 20.48 respectively; p = 0.016). However, there was no association between pain severity and geographic origin in the study population. The association between demographic features and pre-intervention pain and overt anxiety in the two groups is detailed in Table 3.

Table 3.

Pain and overt anxiety before intervention according to demographic features

	Placebo group (n = 50)	Aromatherapy group (n = 50)	Total study population (n = 100)
Pain α *Educational level  Primary and middle school  High school  Collage degree	47.8 ± 23.75 39.0 ± 20.46 33.8 ± 18.34	65.8 ± 23.84 40.7 ± 19.81 35.0 ± 22.51	56.8 ± 24.36 39.9 ± 19.96 34.4 ± 20.1
Pain p-valuea	0.45	0.088	0.045
Anxiety α *Educational level  Primary and middle school  High school  Collage degree	45.7 ± 6.53 46.7 ± 5.52 45.7 ± 6.53	53.2 ± 10.76 44.7 ± 4.6 46.2 ± 4.2	49.5 ± 8.91 45.7 ± 5.11 45.9 ± 5.48
Anxiety p-valuea	0.85	0.21	0.44
Pain α *Geographic origin  Urban  Rural	40.0 ± 20.48 25.4 ± 11.43	41.2 ± 21.4 42.1 ± 28.0	40.6 ± 20.79 34.8 ± 23.3
Pain p-valuea	0.016	0.93	0.364
Anxiety α *Geographic origin  Urban  Rural	46.3 ± 5.96 45.7 ± 5.02	46.6 ± 5.99 43.7 ± 4.0	46.4 ± 5.94 44.6 ± 4.44
Anxiety p-valuea	0.786	0.094	0.158

α: data presented as mean ± Standard deviation; a: ANOVA test

After the intervention, the mean pain level (VAS) in the aromatherapy group was significantly lower than that of the control group when measured at rest (38,76 ± 22,9 vs. 23,84 ± 18,01; p = 0.0002) and after mobilization (60,28 ± 23,72 vs. 40,12 ± 22,18; p = 10^− 6). In addition, the overt anxiety level measured by STAI-Y 1 after the intervention was significantly lower in the aromatherapy arm when compared to the placebo group (46,76 ± 6,59 vs. 44,3 ± 5,17; p = 0.03). However, HR, SBP, DBP, and SPO2 measured after the intervention showed no statistical difference between the two groups (p > 0.05). Only the RR was significantly different between the two groups after the intervention (p = 0.004). Table 4 summarizes the outcomes measured after the intervention.

Table 4.

Outcome parameters measured after the intervention

	Placebo group (n = 50)	Aromatherapy group (n = 50)	p-valuea
Visual Analogue Scale (at rest) (mm) α	38,76 ± 22,9	23,84 ± 18,01	< 0 0.001
Visual Analogue Scale (after mobilisation) (mm) α	60,28 ± 23,72	40,12 ± 22,18	< 0 0.001
STAI-Y1 α	46,76 ± 6,59	44,3 ± 5,17	0.04
Systolic Blood Pressure (mmHg) α	114,4 ± 16,1	111,6 ± 13,4	0.35
Diastolic Blood Pressure (mmHg) α	64,8 ± 0,88	66,2 ± 9,4	0.45
Heart rate (ppm) α	89,4 ± 15,68	86,3 ± 13,8	0.3
Pulsatile Oxygen Saturation (%)α	97,24 ± 2 ,89	97,06 ± 1,73	0.71
Respiratory Rate (cpm) α	20,3 ± 4,51	17,84 ± 5,07	0.004

α: data presented as mean ± Standard deviation; a: Student t-test

As for the need for painkiller medications, patients in the aromatherapy group expressed a significantly lower demand compared to the placebo group (22% versus 58% respectively; p < 10^− 3).

No adverse effects were reported by participants in our study after inhalation, in either the intervention or control groups, and no patient asked for inhalation to be stopped during the procedure, in either the intervention or control groups.

Discussion

In the realm of modern medicine, the use of complementary and alternative therapies has gained increasing recognition as a mean to address various health concerns. One such approach that has shown promising results is the application of aromatherapy in the management of anxiety and pain relief, particularly in the context of post-C-section recovery.

The primary aim of this study was to investigate the effect of lavender essential oil on pain and anxiety levels after cesarean section under spinal anesthesia.

We observed a notable reduction in the pain at rest and after mobilization in the aromatherapy group versus the placebo group. Moreover, overt anxiety level was substantially lower in the aromatherapy arm.

Our findings are clinically significant and relevant and warrant careful consideration regarding their implications for patient care and postoperative recovery. In fact, the reduction in mean pain levels in the aromatherapy group compared to the control group, both at rest and after mobilization, indicate not just statistical significance but also a meaningful improvement in patient comfort. Effective pain management is critical in enhancing the overall patient experience, as high levels of postoperative pain can lead to increased stress, prolonged recovery times, and higher rates of complications. Lower pain levels postoperatively can also facilitate earlier mobilization, which is essential for reducing the risk of complications such as deep vein thrombosis and pulmonary embolism. Early mobilization has been associated with shorter hospital stays and improved recovery outcomes, which are vital considerations in surgical care pathways. In the other side, reducing anxiety levels is crucial as it can exacerbate pain perception and hinder recovery. By effectively managing anxiety through non-pharmacological means such as aromatherapy, healthcare providers can improve patients’ emotional well-being during a vulnerable time. Moreover, the use of lavender EO as a complementary therapy may reduce reliance on other types of analgesics, which are commonly prescribed for postoperative pain management but come with risks of side effects. Lavender aromatherapy also presents a cost-effective strategy for managing postoperative pain and anxiety due to its low cost and minimal side effects compared to traditional pharmacological treatments [21, 22].

In our study, the two groups showed no significant differences regarding individual characteristics. Our results showed that two groups were comparable regarding pain levels and covert and overt anxiety measurements prior to the intervention. Nevertheless, the overt anxiety levels were further down in the aromatherapy group after the intervention, compared to the placebo group. These finding aligns with previous studies that have highlighted the efficacy of aromatherapy using Lavender’s EO in reducing anxiety and pain in adults. Kianpour et al. found that inhaled lavender EO helps reduce postpartum anxiety [23]. In a randomized controlled study published in 2019, Abbasijahromi et al. compared the benefits of aromatherapy with lavender and Damascus rose EO after C-section. The authors proved that aromatherapy with lavender EO reduced significantly the overt anxiety levels [3]. Moghadam et al. studied the results of aromatherapy using lavender EO on the anxiety level of burn patients admitted to the burn unit of Arak Medical University Variasur Hospital. They concluded that aromatherapy with lavender EO lowered anxiety levels and reduced overt and covert fears [24]. Moreover, in a recent randomized controlled study, Lee et al. found that Lavender aromatherapy was responsible for a notable reduction of subjective stress (p < 0.001), and objective stress (p = 0.034) among patients undergoing laparoscopic cholecystectomy [25].

In this study, we evaluated overt anxiety levels 5 min after the intervention. According to Cook et al., anxiety levels decreased immediately after exposure to essential oil inhalation [26]. Moreover, it has been demonstrated that aromatherapy using rose EO positively alleviated anxiety 8 and 16 h after intervention [27]. Beyond its effect on postoperative anxiety, lavender therapy seems to alleviate perioperative anxiety and significantly reduces the need for midazolam [28].

Muzzarelli found no association between inhaled aromatherapy with lavender essential oil and his reduced anxiety levels (p = 0.63) [29]. Likewise, according to their systematic review and metanalyses, Farzan et al. concluded that lavender aromatherapy reduced patients’ pain, but the difference was not statistically significant [30]. These discrepancies may stem from heterogeneity in study design, including sample size, different inclusion criteria, participant characteristics, the specific outcomes measurement techniques and the respect of randomization and blind. Variations in the dosage and method of lavender administration can also significantly influence outcomes. Further studies with robust methodology are needed to provide more evidence on the effects of aromatherapy with lavender EO in this specific patient population.

According to our data, baseline pain intensity levels were comparable between the two groups, with no statistically significant difference observed. Nevertheless, after the intervention, the aromatherapy arm exhibited lower pain levels whether patients were at rest or after mobilization. Olapur et al. studied the impact of inhaled lavender aromatherapy on post-caesarean pain in 60 pregnant women. They concluded that it effectively alleviated pain after cesarean Sect. [31]. Hadi et al. showed that aromatherapy using lavender EO was effective as a complementary treatment to reduce postpartum pain 30mn, 8 h and 16 h after the procedure [32]. Moreover, according to the results of a randomized controlled trial carried out by Abbasijahromi et al., aromatherapy with lavender EO significantly alleviated post-operative pain after C-section compared to the control group [3].

Pain and anxiety can be accompanied by increased heart and respiratory rates, as well as elevated blood pressure. We set these parameters as secondary outcomes in our study. The greater reduction in respiratory rate in the intervention group supports the beneficial effect of aromatherapy in reducing pain and anxiety.

Our study presents several strengths including randomization, respect of double blinding, the implementation of the CONSORT recommendation, and the homogeneity of the two groups. However, the absence of repeated measurements of the outcomes were a limitation to be considered. While our monocentric trial has provided valuable insights into the effects of lavender essential oil on pain and anxiety after cesarean delivery, it is essential to recognize its limitations regarding generalizability. In fact, one of the primary concerns regarding monocentric studies is the potential lack of diversity in the patient population. Conducting a trial at a single site may limit participant demographics, including age, socioeconomic status, ethnicity, and comorbidities. This homogeneity can restrict the applicability of the findings to broader populations. The external validity of our findings may be compromised due to the limited setting. Multicenter studies are generally preferred for their ability to recruit a more heterogeneous patient population across different geographical locations, which enhances the generalizability of results. To address these limitations and enhance the generalizability of findings related to lavender aromatherapy in postoperative care, future research should aim to incorporate multicenter designs to enhance external validity and ensure that findings are applicable across diverse clinical settings. This approach would allow for broader patient recruitment and enhanced statistical power leading to more reliable conclusions.

Conclusion

The use of inhaled aromatherapy with Lavender essential oil seems to be a safe alternative to alleviate both pain and anxiety after C-section. These findings underscore the importance of integrating non-pharmacological interventions like aromatherapy into clinical practice to improve overall management of the birth experience via C-section, and satisfaction in surgical settings in general. Despite the promising results, further research is warranted to enhance the external validity and generalizability of these findings. Future studies should aim to incorporate larger sample sizes and multicenter designs to ensure that results are applicable across diverse populations and clinical settings. Additionally, standardizing intervention protocols regarding dosage, administration methods, and outcome measures will be essential in establishing robust evidence for the efficacy of aromatherapy in various surgical contexts.

Electronic Supplementary Material

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Author Contributions

M.N: Conceptualization, Data curation, Formal analysis, Methodology, Project administration, Writing– original draft, Writing– Review & Editing N.S: Conceptualization, Data curation, Formal analysis, Methodology, Project administration, Writing– original draft, Writing– Review & Editing S.A.K: Investigation, Writing– original draft H.R: Investigation, Writing– original draft A. L: Investigation, Methodology C.M: Conceptualization, Data curation, Formal analysis, Methodology, Project administration, Writing– original draft, Writing– Review & Editing F.Z.R: Resources H.B: Project administration, supervision, validation

Funding

The authors declare they have not received any funding for this study.

Data Availability

No datasets were generated or analysed during the current study.

Declarations

Ethics Approval and Consent to Participate

The study protocol was approved by the local Institutional Review Board (approval no. 03/2023). This trial was registered on clinical-trials.org (NCT06387849) on April 2024.

Competing Interests

The authors declare no competing interests.

All included women gave their informed written consent to take part in the study after explaining its purpose.