In our study for pain that patients feel during and after HSG procedure, we reached some findings that we thought were important. Namely, when we used warm medium we found that patients felt less pain both during and 30 minute after the procedure and the presence of severe pain was more in the cold medium group. Pain felt during the procedure increased as the duration of the procedure increased and this pain was positively associated with the pain felt at 30 minutes after the procedure. However, there was no relationship between the duration of the procedure and the pain felt after the procedure. On the other hand, those who had severe pain during the procedure had a longer procedure time and less frequent use of warm medium. However, in the presence of these two factors, only the medium used was a significant factor for the presence of severe pain.
Pain during the HSG procedure is a troublesome situation for the patient and clinician [14]. The patient may not want to have this procedure done or completed due to this pain. In addition, the clinician can be prevented from reaching an accurate result [15]. Two important mechanisms proposed in the formation of pain that occurs during the HSG procedure are, increased contractions created in the uterus and peritoneal irritation [16, 17]. Increased prostaglandin release in the uterus or the inflammatory response developed due to irritation formed in the peritoneum may cause pain associated with this procedure [18]. Cold stimulation is a factor that increases contraction in the uterus and peritoneal sensitivity [19]. Therefore, in the presence of a cold stimulus, the patient will be expected to experience more pain. Indeed, in 2008, two meta-analyzes by Sammour et al and Sajid et al reported that insufflation with heated CO2 was more advantageous in terms of postoperative pain and analgesia needs [9, 20]. In another more recent meta-analysis by Balayssac et al. it has been reported that warm insufflation is more beneficial for immediate postoperative pain [21]. On the other hand, studies on using warm medium during HSG are limited. To our knowledge, our study is the second study comparing warm and cold contrast agent for HSG. First study was published by Zhu et al in 2012 [12]. In that study, similar to ours, patients’ VAS pain scores during HSG was found to be significantly lower in the warm contrast agent applied group. However, VAS pain scores at 30 minutes after procedure showed no statistical difference. In addition, we found the frequency of severe pain more in the cold group. In our study, the duration of the procedure in the cold group was longer, and the prolongation of this period increased the severity of pain felt during the procedure, and the increased pain during the procedure also increased the pain felt at 30 minutes after the procedure. Extending the duration of the HSG procedure indicates that the procedure is more difficult. This may cause more pain to be felt. As a matter of fact, we found that the duration of the procedure in patients with severe pain was longer than the group without severe pain. Although this can be seen as a factor for the presence of severe pain, we have seen that this negative effect disappears with the use of warm medium in the regression model. We think that this finding shows that the warm medium used during HSG procedure is a very effective factor in reducing HSG-related pain.
A relatively increase in spontaneous pregnancies can be observed after HSG procedure, and a number of theories are proposed as a reason [22]. Tubal flushing during HSG may increase the chance of pregnancy [23]. Depending on the contrast type used, endometrial receptivity and implantation rate may increase [24]. Sperm phagocytosis can be prevented due to the immunological response in the peritoneal cavity, and tubal ciliary activity may also increase [25, 26]. In our study, 4 spontaneous pregnancies were detected in the warm group, but no pregnancy occurred in the cold group during 4-month follow-up period after HSG. This suggests that warm medium may be more beneficial for pregnancy occurrence. However, this finding is a new information for the literature and it should be supported with additional studies with wider participation.
The fact that it is a randomized study on a subject that has not been studied much and that it contains new findings for the literature is the strong features of our study. In addition, the homogeneous groups and the HSG process being performed by the same person and the feature of the contrast material given are not known by the person performing the procedure, provides a more reliable comparison of the results. On the other hand, the relatively small number of participants and the infertile group with certain characteristics may create limitations in generalizing our findings for all infertile patients. In addition, the psychological state of the individuals before the procedure, for example anxiety levels, may affect the level of HSG related pain. It is a limitation that such factors are not evaluated in our study.
As a result, the use of contrast media at body temperature during HSG procedure reduces the pain associated with the procedure. It may also increase the chance of spontaneous pregnancy after the procedure. Nevertheless, additional prospective randomized trials with more participation are needed to achieve the accuracy of such beneficial results in clinical practice.