MATERIALS AND METHODS

Subjects: In this single blind clinical trial, 200 pregnant women at term undergoing elective CS were recruited in Tabriz Taleghani Teaching Centre in a 12-month period of time from June 2010 to June 2011. The patients were randomized in two 100-patient groups and carried into two different rooms 6-8 h post operation. The inclusion criteria were using spinal anesthesia, absence of intra abdominal manipulation/adhesion, no concurrent operation and duration of operation less than 90 min. Emergence of any post CS complications was considered as exclusion criterion.

Visual analogue scale: The severity of pain was documented based on the Visual Analogue Scale (VAS). The VAS is a standard tool like a 10 cm ruler including 10 numbers begin from 0 (no pain) and end to 10 (most severe pain). The patient was asked to select a number based on severity of pain she feels (Johnson, 2005).

Lavender essence: The lavenders (Lavandula) are a genus of 39 species of flowering plants in the mint family, Lamiaceae (Bailey, 1949). In this study, shrubs of the plant were gathered from a plant biology greenhouse, Tabriz University of Medical Sciences. The root and stalk were used for preparing 2% lavender essence. The placebo was artificial aromatic material similar to lavender essence produced by pharmaceutical staff of Tabriz University of Medical Sciences. They confirmed that this was a clinically neutral material in a pilot study.

Study design: At least 3 hours after receiving similar intravenous analgesics, the baseline VAS was recorded. Two drops (about 1 cc) of 2% lavender essence were applied with a cotton swab to the inside of an oxygen face mask in the case group. Patients in the control group received oxygen through a face mask with the placebo. The mask was used for 3 min. Half hour later the VAS was documented again (stage 1). The same processes were repeated again 8 (stage 2) and 16 (stage 3) hours later. Finally, the VAS scores were compared between the two groups.

Statistical analysis: Statistical evaluation was made using SPSS for Windows V 18.0 (SPSS Inc., Il, USA). Data were shown as frequency (percentage) or Mean±standard deviation (SD). Independent samples T, chi-square, Fishers’ Exact and Repeated Measures analysis tests were employed for statistical analysis. The p-values less than 0.05 were regarded as significant.

RESULTS AND DISCUSSION

The two groups were matched for age, education level, occupation, gravidity, parity, previous CS and its number and previous history of abortion and its number. The mentioned variables are summarized and compared between the two groups in Table 1.

Table 1:	Demographics and general data of the patients in two groups
Data are shown as mean±standard deviation or frequency (percentage) p<0.05 is considered statistically significant. Based on this assumption, there was no significant difference with regard the mentioned variables between the two groups

The mean baseline pain score was 6.16±2.03 (range: 1-10) in the case group vs. 5.78±1.97 (2-10) in the controls. The two groups were comparable in this regard (p = 0.18). The mean pain score in the first stage was 3.67±1.60 (range: 1-8) in the case group and 5.29±2.22 (range: 2-10) in the control group. The decrease of pain score in this stage was significantly higher in the case group than that in the controls (p<0.001). In the second stage, it was 2.01±1.20 (range: 0-6) in the case group and 4.64±2.10 (range: 1-9) in the control group. The decrease of pain score in the second stage was again significantly higher in the case group than that in the controls (p<0.001). Finally, in the third stage it was 0.67±0.85 (range: 0-4) in the case group and 4.05±2.23 (range: 0-9) in the control group. The decrease of pain score in the third stage was significantly higher in the case group than that in the controls (p<0.001). In intra-group analysis, the mean pain score decreased significantly in both group from baseline to the end of study period (p<0.001 for both groups). Changes of mean pain scores during the study period are shown in Fig. 1.

The post CS pain control is still a big challenge for obstetricians. Currently, it is generally believed that the conventional monotherapies may not be efficient or safe in this regard. Alternative or complementary therapies have been proposed in pain management (Sahebihag et al., 2011). Based on this fact, the current study aimed to evaluate the effect of aromatherapy, as an alternative therapy, in reducing pain after cesarean section. The analgesic property of lavender essence has been previously reported in post-cosmetic procedures (Grunebaum et al., 2011), climacteric women (Hur et al., 2008), hospice patients with terminal cancer (Chang, 2008), chronic pain (Ostermann et al., 2008), laparoscopic gastric banding (Kim et al., 2007), stroke (Shin and Lee, 2007) and breast biopsy (Kim et al., 2006). All these data emphasize on antinociceptive property of lavender oil/essence.

Fig. 1:	Changes of mean pain score on the visual analogue scale from baseline to the end of study in the cases and the controls

The analgesic property of the lavender essence was also confirmed in the present study and so the results are in conformity with other reports. Efficacy of lavender oil/essence in relief of obstetric pain has been previously shown in postnatal perineal discomfort (Dale and Cornwell, 1994; Cornwell and Dale, 1995). The results of these two studies are also in conformity with our findings. However, it should be noticed that they used the lavender oil in bath for 10 days after vaginal delivery instead of aromatherapy. Vakilian et al. (2011) suggested application of lavender essential oil instead of povidone-iodine for episiotomy wound care after vaginal delivery. This study also confirmed the analgesic property of lavender oil in pregnant women after episiotomy without assessment of its aroma in this regard. This indicates efficacy and safety of this material after delivery, even in presence of open surgery wound. So, application of the material is safe in cesarean section, which was investigated in the current study. As mentioned earlier, for the first time in this study, it is shown that aromatherapy with lavender essence is effective in control of post CS pain. Based on these findings, aromatherapy could be used as an effective and safe complementary therapy for controlling pain after CS. This could effectively cut consumption of other routine costly and potentially harmful medications. As the present study is innovative, further multicentre studies will help the physicians to better decision-making. Maybe in future, the current medications could be replaced by aromatherapy after CS.

CONCLUSION

Aromatherapy by using lavender essence is effective in reducing pain after CS in women. This method is safe and easy to perform. However, it is only recommendable as a complementary method along with routine pain management.