Abstract
Background
To evaluate the best maternal point of visual focusing (PVF) for minimizing pain and anxiety during amniocentesis.
Methods
A prospective randomized study was conducted to compare pain and anxiety levels assessed by a visual analogue scale (VAS) on anticipated and perceived pain after amniocentesis between three groups of pregnant women who underwent amniocentesis with three different PVF. Differences between means of anticipated and perceived pain in each maternal PVF were also evaluated.
Results
A total of 105 participants were enrolled and randomly assigned to covered maternal eyes, independent PVF and adapted visual reality (VR) groups, respectively. The mean VAS scores of anticipated pain and perceived pain were not significantly different between each different maternal PVF. The mean VAS of perceived pain was significantly lower than that of anticipated pain in all maternal PVF groups. The different mean VAS scores (95% confidence interval: CI) were 1.50 (0.28–2.71), p-value 0.017 in the maternal covered eyes group, 1.17 (0.16–2.18), p-value 0.025 in the independent PVF group and 0.96 (0.06–1.86), p-value 0.037 in the adapted VR group.
Conclusion
Covered maternal eyes, independent PVF and adapted VR can all be similarly recommended as the best maternal PVF during amniocentesis.
Trial registration
Srinakharinwirot ethics committee (SWUEC/E/M-059/2565) and Thai Clinical Trials Registry TCTRID20221022003 (19 October2022).
Keywords: Genetic amniocentesis, Pain, Point of visual focusing
Background
Second trimester amniocentesis for a prenatal genetic diagnosis is a common invasive procedure during pregnancy. Although several aneuploidy screening methods have been widely introduced in the last decade, the fetal genetic material derived from this invasive procedure is still needed for definite diagnosis. Compare with chorionic villus sampling and fetal blood sampling, amniocentesis is a safer modality [1]. In Thailand, pregnancy loss after second trimester genetic amniocentesis is reported at an approximate rate of 0.1% [2]. Along with the concern about pregnancy loss, most pregnant women express apprehension regarding the pain and discomfort symptoms related to the procedure. Many previous studies have evaluated modalities aiming to reduce the pain and anxiety associated with second trimester genetic amniocentesis such as cryoanalgesia, aromatic therapy and music therapy [3–5]. Cryoanalgesia has been effectively proven for pain and anxiety alleviation [5]. Besides the modalities for pain and anxiety alleviation, the behavior of pregnant women during the procedure is also one of our interests, especially the best maternal point of visual focusing (PVF). Pregnant women’s visual behavior during amniocentesis varies, such as closing their eyes, looking around, or looking at the ultrasonographic (US) screen. Depending on the individual PVF of each pregnant woman, the operator may have to deal with the pregnant women’s different responses to the US image, such as crying, tensing up or pulling back their body when they see the needle piercing the uterus and gestational sac, and it is unclear whether these responses interfere with the technical difficulty, success rate, or safety of the procedure. Virtual reality (VR) is a new tool that is increasingly being considered as a potential PVF medical intervention. VR is a technology used for organizing an artificial environment to replace a real-world situation [6]. Previous studies have revealed the usefulness of VR application as an adjunctive tool for chronic pain relief [7]. However, the effectiveness of VR application for acute pain is still limited and it has not been evaluated for amniocentesis pain and anxiety relief, including in Thailand. Thus, we conducted the present study to search for the best maternal PVF during second trimester amniocentesis. The primary objective was to compare the perceived pain scores (PP) between three different maternal PVF (covered maternal eyes, independent PVF and adapted VR). The pain scores measured by using a visual analogue scale (VAS). And the secondary objective was to compare the procedural outcomes according to each maternal PVF.
Methods
This prospective randomized controlled trial was conducted at HRH Princess Maha Chakri Sirindhorn Medical Center, Srinakharinwirot University, Thailand, during November 2022 to November 2023. Singleton pregnant women undergoing amniocentesis between 16 and 20 weeks of gestation was enrolled. The study was approved by the institute’s ethics committee (SWUEC/E/M-059/2565) and was registered on the Thai Clinical Trials Registry (TCTR 20221022003). Pregnant women with presence of fetal structural abnormality, blindness or refusal to participate the study were excluded.
Pregnant women were counseled about both second trimester genetic amniocentesis and our study, then each pregnant woman was asked to consent for both amniocentesis and participation in our study.
All participants were asked for their demographic data (maternal age, body mass index (BMI), race, religion, occupation, education level, family income, gravida, parity, history of abortion, history of previous abdominal surgery, history of amniocentesis in previous pregnancies and indication for current amniocentesis). After that, all participants were assessed to indicate their anticipated pain scores (AP) before undergoing the procedure by using a visual analog scale (VAS). The participants were asked to indicate their pain level as a point along a 10-centimeter horizontal line. The end on the left hand side was numbered as zero or “no pain” and the pain levels gradually increased to the end on the right hand side, which was numbered as 10 or “the worst possible pain”. A pain level score between 0 and 10 was determined by measuring the length in millimeters from the end of the line on the left hand side to the point that the participant had marked. Then, all participants were randomly assigned into one of the three different maternal PVF groups either the covered maternal eyes group, the independent PVF group or the adapted VR group, which were described as follows:
-
i)
Covered maternal eyes group: both eyes of the participant were covered with a clean opaque green cloth from the forehead to the base of the nose.
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ii)
Independent PVF group: both eyes of the participant were open and participants were free to look around during the procedure if they preferred.
-
iii)
Adapted VR group: a video featuring beautiful scenic landscapes was provided, and it was accompanied with relaxing instrument music. piano music.
After blocked randomization, all participants underwent US examination for fetal number, fetal viability, placental location, biometry and evaluation of the amount of amniotic fluid. After the US had finished, the maternal PVF was provided to participants according to their randomized groups until the end of the needle removal process. Then the amniocentesis procedure was started. All amniocentesis was performed under continuous US guidance, and a hands-free technique was used with a 22-gauge spinal needle by a Maternal Fetal Medicine Training Program fellow, with supervision by the Maternal Fetal Medicine staff who had received the maternal fetal medicine diploma from the Royal Thai College of Obstetricians and Gynaecologists. No local anesthetic or other analgesic was used during the procedure. During all procedures, 16–20 mL of amniotic fluid was routinely withdrawn, and the number of punctures and type of amniocentesis (transplacental or transamniotic approach) and duration of procedure and fetal cardiac activity were immediately checked post-procedure and recorded. Then all participants rested for at least 30 min before discharge from our antenatal clinic. Immediately after the procedure, each participant was asked to mark the VAS score of their PP during amniocentesis by a nurse who did not know the maternal PVF randomized group. The operator was also asked to assess their feeling with regard to the difficulty level by using the VAS. However, blinding of the operator was not feasible due to space limitations.
Statistical analysis
The required sample size was estimated by using a formula for a randomized controlled trial to compare the difference in means between two groups. In a previous study, mean pain VAS scores were 2.5 cm and 3.8 cm in pregnant women who underwent amniocentesis with and without VR, respectively [8]. To achieve an alpha of 0.05, a beta error of 80%, and allowing for 20% lost or missing data, the sample size required for each group was 35 participants. The baseline characteristics were presented by percentages or means and standard deviations or the medians and interquartile ranges (IQR) and then compared using ANOVA and the Chi-square test. The means of the AP and PP VAS scores were compared between the three groups using ANOVA and ANCOVA, respectively. Lastly, the difficulty of the procedure was compared using the Chi-square test, ANOVA and Kruskal-Wallis test. In all statistical tests, p-values of < 0.05 were considered significant.
Results
A total of 105 pregnant women who underwent second trimester amniocentesis were recruited and randomly assigned to the covered maternal eyes, independent PVF and adapted VR groups. All participants completed the study protocol. (Fig. 1) Table 1 shows no significant differences of all of the patients’ demographic characteristics between the three groups. No complications were observed during, immediately after, or two weeks following the procedure.
Fig. 1.
Consort Flow Diagram
Table 1.
Demographic characteristics of the participants (n = 105)
| Covered maternal eyes (35) |
Independent PVF (35) |
Adapted VR (35) |
p-value | |
|---|---|---|---|---|
| Age (years) | ||||
| Mean ± SD | 32 ± 8.5 | 32.1 ± 5.7 | 33.3 ± 6.4 | 0.687* |
| Range | 12–48 | 21–41 | 19–44 | |
| Body mass index (kg/m2) | ||||
| Mean ± SD | 23.26 ± 4.68 | 22.85 ± 2.99 | 25.13 ± 5.28 | 0.076* |
| Range | 16.02–38.30 | 18.07–30.40 | 18.00–35.90.00.90 | |
| Education, n (%) | ||||
| Junior high school or lower | 11 (31.4) | 6 (17.1) | 8 (22.9) | 0.692** |
| Senior high school-Bachelor’s degree | 23 (65.7) | 27 (77.2) | 25 (71.4) | |
| Higher than bachelor’s degree | 1 (2.9) | 2 (5.7) | 2 (5.7) | |
| Occupation, n (%) | ||||
| Employee | 15 (42.9) | 15 (42.9) | 15 (42.9) | 0.700** |
| Housewife | 4 (11.4) | 4 (11.4) | 3 (8.5) | |
| Government officer | 6 (17.1) | 7 (20) | 8 (22.9) | |
| Other | 10 (28.6) | 9 (25.7) | 9 (25.7) | |
| Religion, n (%) | ||||
| Buddhist | 32 (91.4) | 30 (85.7) | 29 (82.9) | 0.562** |
| Muslim | 3 (8.6) | 5 (14.3) | 6 (17.1) | |
| Previous amniocentesis, n (%) | ||||
| Yes | 2 (5.7) | 5 (14.3) | 4 (11.4) | 0.470** |
| No | 33 (94.3) | 30 (85.7) | 31 (88.6) | |
| Previous abdominal surgery, n (%) | ||||
| Yes | 9 (25.7) | 10 (28.6) | 11 (31.4) | 0.511** |
| No | 26 (74.3) | 25 (71.4) | 24 (68.6) | |
| Indication, n (%) | ||||
| Maternal request | 2 (5.7) | 1 (2.8) | 3 (8.6) | 0.504** |
| Age ≥ 35 years | 6 (17.2) | 10 (28.6) | 7 (20) | |
| Abnormal screening test | 25 (71.4) | 24 (68.6) | 22 (62.8) | |
| Couple at risk for thalassemia | 2 (5.7) | 0 (0) | 3 (8.6) | |
*ANOVA **Chi-square test
Table 2 presents the mean VAS scores of AP and PP of each group. The mean VAS scores of AP and PP were not significantly different between each different maternal PVF. The differences between AP and PP were statistically significant in all maternal PVF groups. The mean VAS scores (95% confidence interval: CI) of PP were significantly lower than those of AP in all groups. The differences of mean VAS scores (95% CI) were 1.50 (0.28–2.71), p-value 0.017, in the maternal covered eyes group; 1.17 (0.16–2.18), p-value 0.025 in the independent PVF group; and 0.96 (0.06–1.86), p-value 0.037 in the adapted VR group.
Table 2.
Mean VAS scores of anticipated pain and perceived pain during amniocentesis
| Covered maternal eyes (n = 35) |
Independent PVF (n = 35) |
Adapted VR (n = 35) |
p-value | |
|---|---|---|---|---|
| Anticipated pain (cm) | 4.97 ± 2.68 | 5.52 ± 2.41 | 4.63 ± 2.42 | 0.334* |
| Perceived pain during amniocentesis (cm) | 3.47 ± 2.23 | 4.35 ± 2.46 | 3.67 ± 2.63 | 0.472** |
*ANOVA **ANCOVA
Table 3 shows the comparison of procedural difficulty between the three groups. No significant differences were found between the three groups for any of the procedural difficulty variables.
Table 3.
Comparison of procedural difficulty
| Covered maternal eyes (n = 35) |
Independent PVF (n = 35) |
Adapted VR (n = 35) |
p-value | |
|---|---|---|---|---|
| Number of punctures, n (%) | ||||
| 1 | 35 (100) | 34 (97.1) | 34 (97.1) | 0.601* |
| > 1 | 0 (0) | 1 (2.9) | 1 (2.9) | |
| Time (seconds) | ||||
| Median (IQR) | 30 (20–40) | 30 (24–45) | 35 (20–60) | 0.218** |
| Trasnsplacental approach, n(%) | 7 (20) | 12 (34.3) | 6 (17.1) | 0.196* |
| Mean VAS scores for the operator’ s feeling of difficulty (cm) | 1.86 ± 1.78 | 2.68 ± 1.95 | 2.52 ± 2.35 | 0.208*** |
*Chi-square test ** Kruskal-Wallis ***ANOVA
Discussion
Amniocentesis is a standard method used for prenatal aneuploidy and genetic diagnosis. Pregnant women are concerned about pain and several previous studies have identified modalities that reduce pain and anxiety during the procedure [3–5]. However, researchers have been less concerned about the behavior and position of pregnant women, and there has still been no scientific study which supports ideas on how to properly manage the posture or behavior of pregnant women who undergo amniocentesis. The best maternal PVF during amniocentesis has never been evaluated. To date, our study is the first to evaluate the best maternal PVF during amniocentesis in terms of PP. Before our study, it was still complicated to arrange where pregnant women should point their eyes. Most procedure depends on the satisfaction of the operator or the pregnant woman herself. Their satisfactory is sometimes conflicted; for example, the operators feel uncomfortable if the pregnant women stare at them during the procedural process. In contrast, some pregnant women feel uncomfortable when covered their eyes, while some are afraid when the see the needle pass into their womb. VR is a novel adjunctive pain management tool which has been introduced into several medical situations, aiming for pain or anxiety reduction or physical relaxation in both acute and chronic conditions [9–12]. It has been postulated that a period of time spent in a virtual world might lead to closure of the neural pain gateways, helping to block pain signals from reaching the brain for long enough to provide a longer analgesic-free interval [12, 13]. Our study found that the adapted VR was effective but not superior to the other PVF groups in pregnant women who underwent amniocentesis. This is similar to a previous study which found VR was significantly effective in reducing pain during amniocentesis [14].
Regarding our main point of interest, the best maternal PVF, both AP and PP were not significantly different between the three different maternal PVF (covered maternal eyes, independent PVF and adapted VR). That means, there were no definitive maternal PVF that was most preferred by the pregnant women during amniocentesis, based on the means found for PP in different groups. We also found that the mean VAS scores for the operator’ s feeling of difficulty during operation were also not significantly different. This is an advantage of our study in that it focuses on the feelings from both the perspectives of the operators performing the procedures and those of the pregnant women undergoing the procedures. However, we did not strictly design the study to definitely control compliance with the maternal PVF, for example, when some participants in the VR group may not have actually watched the VR. This response was reported in a study on reducing feeling of anxiety when using VR in women visiting a one-stop clinic for abnormal uterine bleeding. They reported that around 57.5% of the participants did not comply with their protocol [10]. In addition, our study did not evaluate the participants’ satisfaction with their assigned protocol. Some participants may have disliked or been uncomfortable with their assigned protocol. Their dislike or discomfort may have influenced their compliance which have had an effect on the results of the study. Poor compliance prevents pregnant women from being exposed to the synthetic world as a VR mechanism. In any case, we postulated that compliance should not be too strictly controlled because it may make the procedure uncomfortable for the participants. Future studies may allow pregnant women to choose their preferred PVF. Compare to previous studies on alternative modalities for pain relief during amniocentesis, only the modalities which were found to directly affect the neural pathways such as cryoanalgesia or cold therapy and local anesthetic infiltration, could significantly reduce perceived pain [5, 15]. Meanwhile, most of the modalities which had distracting mechanisms were not found to be significantly effective in reducing perceived pain [3, 4]. We hypothesize that pain occurring in pregnant women may be more complicated than in other non-pregnancy situations because pregnant women have physical adaptations such as swelling, retention of fluid or sleep deprivation accompanied with concerns about the fetus. Therefore, using a distracting modality only may not be enough to control or reduce pain.
Conclusion
According to our study results, we should counsel our pregnant women who will undergo amniocentesis that most pregnant women feel the PP level after amniocentesis is lower than their AP level, independent of maternal PVF. Pregnant women undergoing amniocentesis may be counseled that they can flexibly choose their PVF (covered maternal eyes, independent PVF and adapted VR) because the maternal PVF does not affect the levels of discomfort or difficulty experience during the procedure.
Acknowledgements
The authors would like to thank the professional English language editing staff at the International College for Sustainability Studies of Srinakharinwirot University, Bangkok, Thailand for his editorial assistance. We declare that we have no conflict of interest.
Abbreviations
- PVF
Point of visual focusing
- VAS
Visual analogue scale
- VR
Adapted visual reality
- AP
Anticipated pain scores
- PP
Perceived pain scores
- CI
Confidence interval
- US
Ultrasonographic
- BMI
Body mass index
- IQR
Interquartile ranges
Authors’ contributions
All authors reviewed the manuscript.
Funding
Srinakarinwirot university.
Data availability
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.
Declarations
Ethics approval and consent to participate
Informed consent for participation was obtained from all participants. Before the study was conducted, ethical approval to conduct the study was obtained from the Srinakharinwirot ethics committee (SWUEC/E/M-059/2565). The study was carried out in accordance with the Declaration of Helsinki.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.