Abdominal skeletal muscle activity precedes spontaneous menstrual cramping pain in primary dysmenorrhea

Ultrasound and magnetic resonance imaging-based investigation of the role of perfusion and oxygen availability in menstrual pain

BACKGROUND

The mechanisms responsible for menstrual pain are poorly understood. However, dynamic, noninvasive pelvic imaging of menstrual pain sufferers could aid in identifying therapeutic targets and testing novel treatments.

OBJECTIVE

To study the mechanisms responsible for menstrual pain, we analyzed ultrasonographic and complementary functional magnetic resonance imaging parameters in dysmenorrhea sufferers and pain-free controls under multiple conditions.

STUDY DESIGN

We performed functional magnetic resonance imaging on participants with and those without dysmenorrhea during menses and outside menses. To clarify whether regional changes in oxygen availability and perfusion occur, functional magnetic resonance imaging R2∗ measurements of the endometrium and myometrium were obtained. R2∗ measurements are calculated nuclear magnetic resonance relaxation rates sensitive to the paramagnetic properties of oxygenated and deoxygenated hemoglobin. We also compared parameters before and after an analgesic dose of naproxen sodium. In addition, we performed similar measurements with Doppler ultrasonography to identify if changes in uterine arterial velocity occurred during menstrual cramping in real time. Mixed model statistics were performed to account for within-subject effects across conditions. Corrections for multiple comparisons were made with a false discovery rate adjustment.

RESULTS

During menstruation, a notable increase in R2∗ values, indicative of tissue ischemia, was observed in both the myometrium (beta ± standard error of the mean, 15.74±2.29 s-1; P=.001; q=.002) and the endometrium (26.37±9.33 s-1; P=.005; q=.008) of participants who experienced dysmenorrhea. A similar increase was noted in the myometrium (28.89±2.85 s-1; P=.001; q=.002) and endometrium (75.50±2.57 s-1; P=.001; q=.003) of pain-free controls. Post hoc analyses revealed that the R2∗ values during menstruation were significantly higher among the pain-free controls (myometrium, P=.008; endometrium, P=.043). Although naproxen sodium increased the endometrial R2∗ values among participants with dysmenorrhea (48.29±15.78 s-1; P=.005; q=.008), it decreased myometrial R2∗ values among pain-free controls. The Doppler findings were consistent with the functional magnetic resonance imaging (-8.62±3.25 s-1; P=.008; q=.011). The pulsatility index (-0.42±0.14; P=.004; q=.004) and resistance index (-0.042±0.012; P=.001; q=.001) decreased during menses when compared with the measurements outside of menses, and the effects were significantly reversed by naproxen sodium. Naproxen sodium had the opposite effect in pain-free controls. There were no significant real-time changes in the pulsatility index, resistance index, peak systolic velocity, or minimum diastolic velocity during episodes of symptomatic menstrual cramping.

CONCLUSION

Functional magnetic resonance imaging and Doppler metrics suggest that participants with dysmenorrhea have better perfusion and oxygen availability than pain-free controls. Naproxen sodium's therapeutic mechanism is associated with relative reductions in uterine perfusion and oxygen availability. An opposite pharmacologic effect was observed in pain-free controls. During menstrual cramping, there is insufficient evidence of episodic impaired uterine perfusion. Thus, prostaglandins may have protective vasoconstrictive effects in pain-free controls and opposite effects in participants with dysmenorrhea.

Scientific Knowledge Graph of Dysmenorrhea: A Bibliometric Analysis from 2001 to 2021

Purpose

This study aims to help researchers master the most active hotspots and trends quickly through bibliometric analysis in the field of dysmenorrhea.

Methods

We retrieved literature on Web of Science from 2001 to 2021, and bibliometric analysis software CiteSpace was used in combination with VOSviewer.

Results

We finally acquired 944 papers and an upward trend in articles continued in this field overall. Through the map, China contributed the most, followed by the USA and Turkey. For institutions, Beijing University of Chinese Medicine in China contributed the most, followed by National Yang-Ming University in Taiwan, China. Hsieh JC and Hellman KM were both the most prolific authors with 14 articles. Five major research groups, respectively, with Hsieh JC, Hellman KM, Zhu J, Liang F and Dun W were the key group. Dawood MY was the most dominant author and most frequently cited author. The Cochrane Database of Systematic Reviews Journal was the most productive, and the Fertility and Sterility Journal was the most cited. Advances in pathogenesis and management for primary dysmenorrhea written by Dawood MY was most cited and influential. Pathophysiology, the potential central mechanism, syndrome, evaluation index, diagnosis of adenomyosis-associated dysmenorrhea, treatment, etc., were the main trends and hotspots.

Conclusion

Dysmenorrhea research has received a lot of attention from scholars. Strengthening international cooperation may promote the development of this field. The pathophysiology of dysmenorrhea, its impact on public health and its treatment are current research hotspots and are likely to be the focus of future study.

Effect of Lumbar Spine Mobility and Postural Alignment on Menstrual Pain in Young Women

(1) Background: Studies indicate that 45 to 95% of women suffer from painful periods. Despite frequent incidence, the problem is still underestimated. Menstruation-related ailments often correlate with high absenteeism at school and work, as well as limitation of social and scientific activity. The aim of this study was to assess the relationship between the size of the curvature, the mobility of the spine in the sagittal plane, and menstrual pain in young women. (2) Methods: The analysis included 224 women aged 18-26, mean of 21.56 ± 1.95, studying at the College of Medical Sciences of the University of Rzeszów. For this purpose, the measurement of the anterior-posterior curvature of the spine with a gravitational inclinometer, the Schober test and the authors' questionnaire related to menstruation were used. (3) Results: The data analysis demonstrated a significant difference between the group with menstrual pain (MP) and the control group without pain (CG), where the angle of the lumbar sacral transition (p = 0.034), thoracolumbar transition (p = 0.044) and lumbar lordosis (p = 0.006) were statistically significantly lower in MP compared to CG. There were no significant differences in the measurement of the so-called smartphone hump and between the mobility of the lumbar spine and menstrual pain in any of the groups. (4) Conclusions: Women with menstrual pain are characterized by reduced lumbar lordosis and thoracic kyphosis, while sagittal mobility of the spine does not affect pain.

Prevalence of menstrual symptoms change and influencing factors among international female students studying in china during acculturation period

Background

A number of previous studies have explored international students’ adaptation process with regards to language, lifestyle, food, and environment. However, there have yet been no studies conducted to address the menstrual symptoms challenges faced by international female students during the acculturation period. Thus, this study aims to describe the prevalence of menstrual symptoms change and to explore the influencing factors among international female students studying in China during the acculturation period.

Methods

An online cross sectional study was conducted among international female students studying in China during the acculturation period (defined as the first six months of living in the host country) in Hunan Province of China from March 2019 to July 2019. Menstrual symptoms questionnaire, sociocultural adaptation scale, China higher education student satisfaction scale, perceived stress scale, and Pittsburgh sleep quality index were used for data collection. Descriptive analysis, ANOVA, paired t-test, Pearson correlation, and multivariate linear regressions were used to analyze the data using SPSS 21.0 software.

Results

Three hundred and forty-five (97.18%, 345/355) female students from 45 countries fully completed the questionnaire. The mean age of the participants was (26.59 ± 6.439) years. In total, 18.49% of participants had encountered menstrual symptoms change. There were significant differences in the menstrual symptoms score between before arrival and evaluation during the first six months of living in China (t = − 11.700, p = 0.000). The main menstrual symptoms change included cramps (17.68%), irritation (14.78%), abdominal pain (12.46%), fatigue (12.46%), and headaches (9.85%). Cultural adaptation level (β = 0.198, 95% CI: 0.934, 2.995), sleep quality (β = 0.166, 95% CI: 0.112, 0.496), perceived stress (β = 0.193, 95% CI: 0.123, 0.410), time spent in the host environment, (β = − 0.270, 95% CI: − 3.200, − 1.444) and experience of visiting foreign countries (β = 0.184, 95% CI: 1.134, 4.125) were significantly correlated with menstrual symptoms change.

Conclusion

The prevalence of menstrual symptoms change among international female students should not be overlooked when considering menstrual health in this population. Poorer cultural adaptation, poorer sleep quality, higher stress, and lack of overseas living experiences significantly influence the menstrual symptoms of international female students studying in China.

The Menstrual Disorder of Teenagers (MDOT) Study No. 2: Period ImPact and Pain Assessment (PIPPA) Tool Validation in a Large Population-Based Cross-Sectional Study of Australian Teenagers

STUDY OBJECTIVE

To validate the Period ImPact and Pain Assessment (PIPPA) self-screening tool for menstrual disturbance in teenagers.

DESIGN

Cross-sectional study.

SETTING

Three senior high schools in the Australian Capital Territory (ACT), Australia.

PARTICIPANTS

A total of 1066 girls between 15 and 19 years of age.

INTERVENTIONS AND MAIN OUTCOME MEASURES

A quantitative paper survey collected self-reports of menstrual bleeding patterns, typical and atypical symptoms, morbidities, and interference with daily activities. Multiple correspondence analysis was used to examine associations between PIPPA questions. Generalized linear models compared total score and subscores by validation criteria: pain, school absence, and body mass index (BMI). Receiver operating characteristic curves were used to evaluate the predictiveness of menstrual disturbance indicators by total PIPPA score.

RESULTS

Reports of pain, interference, and concern within the PIPPA items and between both the MDOT and PIPPA questionnaires were significantly correlated (P < .0001). The indicator "missing school" was highly associated (P < .0001) with pain and interference. Obesity (BMI ≥30) was associated with higher PIPPA scores, as was underweight (BMI≤18.4). Where 0 = no disturbance, 5 = high disturbance, aggregated PIPPA scores found 75% scoring 0-2 (out of 5) and 25% scoring 3-5 (257/1037). High scores of 4 or 5 (out of 5) were 7% (72/1037) and 3.7% (38/1037), respectively.

CONCLUSION

PIPPA is a valid screening tool for pain-related menstrual disturbance that affects functioning in young women. PIPPA subdomains of pain/interference have good validity relative to indicators of pain and interference and are responsive to age, BMI, and school absence differences.

Development and validation of a real-time method characterizing spontaneous pain in women with dysmenorrhea

AIM

Prior research has primarily focused on static pain assessment, largely ignoring the dynamic nature of pain over time. We used a novel assessment tool for characterizing pain duration, frequency, and amplitude in women with dysmenorrhea and evaluated how these metrics were affected by naproxen treatment.

METHODS

Dysmenorrheic women (n = 25) rated their menstrual pain by squeezing a pressure bulb proportional to the magnitude of their pain. To evaluate whether bulb squeezing was affected by naproxen, we compared parameters before and after naproxen. We also analyzed the correlation between pain relief on a numerical rating scale to changes in bulb squeezing parameters. Random bulb-squeezing activity in pain-free participants (n = 14) was used as a control for nonspecific effects or bias.

RESULTS

In dysmenorrheic women, naproxen reduced the duration of the squeezing during a painful bout, the number of painful bouts and bout intensity. Before naproxen, the correlation between these bulb squeeze parameters and self-reported pain on numeric rating scale was not significant (R² = 0.12, p = 0.304); however, there was a significant correlation between changes in bulb squeeze activity and self-reported pain relief after naproxen (R² = 0.55, p < 0.001).

CONCLUSION

Our study demonstrates a convenient technique for continuous pain assessment, capturing three different dimensions: duration, frequency, and magnitude. Naproxen may act by reducing the duration and frequency of episodic pain in addition to reducing the severity. After further validation, these methods could be used for other pain conditions for deeper phenotyping and assessing novel treatments.

Low Serum Naproxen Concentrations Are Associated with Minimal Pain Relief: A Preliminary Study in Women with Dysmenorrhea

OBJECTIVE

Incomplete pain relief after administration of nonsteroidal anti-inflammatory drugs (NSAIDs) is common, but it is unknown whether malabsorption or heightened metabolism contributes to NSAID resistance. To explain the etiology of NSAID resistance, we evaluated naproxen absorption and metabolism in relation to pain relief in a pilot study of women with dysmenorrhea.

METHODS

During menses, participants completed before and after naproxen ingestion pain assessments. Analgesic effectiveness was calculated as a percent change in pain rating before and after naproxen administration. To evaluate the impact of malabsorption, the correlation between analgesic effectiveness and serum naproxen was analyzed. To identify whether hypermetabolism contributes to NSAID resistance, we also analyzed the metabolite O-desmethylnaproxen.

RESULTS

Serum naproxen and O-desmethylnaproxen concentrations of the dysmenorrheic cohort (N = 23, 126 ± 10 µg/mL, 381 ± 56 ng/mL) and healthy controls (N = 12, 135 ± 8 µg/mL, 355 ± 58 ng/mL) were not significantly different (P > 0.05), suggesting that menstrual pain does not affect drug absorption and metabolism. However, nine dysmenorrhea participants had levels of analgesic effectiveness <30%. Among dysmenorrheic women, analgesic effectiveness was correlated with serum naproxen (r = 0.49, P = 0.019) and O-desmethylnaproxen (r = 0.45, P = 0.032) concentrations. After controlling for other gynecological diagnoses, a multivariate model analysis confirmed that lower serum naproxen concentrations were associated with reduced pain relief (P  = 0.038).

CONCLUSIONS

Our preliminary findings suggest that poor drug absorption contributes to ineffective pain relief in dysmenorrheic women. Future studies should explore whether malabsorption contributes to NSAID resistance for other pain conditions.

Ultrasound Assessment of the Abdominal Wall Muscles in Women with and without Primary Dysmenorrhea: A Cross-Sectional Study

Background: Primary dysmenorrhea (PD) is one of the most common gynecological disorders in women of reproductive age that may affect quality of life. It is believed that the underlying cause of PD may be the excessive production of prostaglandins (PGs), however, between 20%–25% of women with PD did not respond to pharmacological treatments, showing that nociceptive mechanisms underlying PD are still not understood. The purpose of this study was to measure and compare, through the use of ultrasound imaging, the thickness at rest of the abdominal wall, as well as the interrecti distance (IRD), in women with and without PD. Methods: A cross-sectional study has been performed using ultrasound imaging (USI) to measure the resting thickness of the external oblique (EO), internal oblique (IO), transversus abdominis (TrAb), rectus abdominis (RA), as well as the IRD in a sample of 39 women, 19 with PD and 20 without PD (median ± IR age: 20 ± 4 and 22.5 ± 7 years, respectively). Results: Findings of muscular thickness did not reveal statically significant differences (p < 0.05) in EO, IO, TrAb, RA, and the IRD between the PD group and control group. Conclusions: These findings suggest that the thickness of the abdominal wall is not associated with PD.

Low Serum Oxytocin Concentrations Are Associated with Painful Menstruation

Oxytocin-dependent mechanisms are hypothesized to contribute to painful menses, but clinical trials of oxytocin antagonists for dysmenorrhea have had divergent outcomes. In contrast, broader studies have shown that increased systemic oxytocin concentrations are associated with increased pain tolerance and improved psychosocial function. We sought to confirm whether increased serum oxytocin concentrations are associated with menstrual pain and other psychosocial factors. Women with a history of primary dysmenorrhea (n = 19), secondary dysmenorrhea (n = 12), and healthy controls (n = 15) completed pain and psychosocial questionnaires, provided a medical history, and rated their pain during the first 48 h of menses. Serum samples were collected during menses to measure oxytocin concentrations. Oxytocin was significantly lower in participants with a history of primary (704 ± 33 pg/mL; p < 0.001) or secondary (711 ± 66 pg/mL; p < 0.01) dysmenorrhea compared to healthy controls (967 ± 53 pg/mL). Menstrual pain over the past 3 months (r = -0.58; p < 0.001) and during the study visit (r = -0.45; p = 0.002) was negatively correlated with oxytocin concentrations. Pain catastrophizing (r = -0.39), pain behavior (r = -0.32), and pain interference (r = -0.31) were also negatively correlated with oxytocin levels (p's < 0.05). Oxytocin was not significantly correlated with psychosocial factors. Contrary to our hypothesis, women with a history of primary or secondary dysmenorrhea had lower oxytocin concentrations during menses when compared to healthy controls. Lower circulating oxytocin concentrations were also associated with worse menstrual pain and pain-related behavior. When considering the existing literature, low circulating oxytocin may be a sign of dysfunctional endogenous pain modulation.

Experimental evaluation of central pain processes in young women with primary dysmenorrhea

Primary dysmenorrhea (PD; menstrual pain without an underlying medical condition) is associated with enhanced pain sensitivity and temporal summation (TS) in adult women, which may reflect the presence of central pain processes. Research in this area has been limited by focusing on only adult populations and incomplete assessments of central sensitization. The current study explored both excitatory and inhibitory measures of pain processing in girls and young adult women with and without PD. Thirty-two young women with PD and 34 healthy controls underwent laboratory pain testing during each of 3 menstrual cycle phases (menstrual, ovulatory, and midluteal), which included measures of pain tolerance and threshold, TS, and conditioned pain modulation. Results indicated enhanced pain sensitivity in young women with PD as measured by heat pain tolerance and Average Pain50 (P50), compared with healthy controls. These group differences were evident at all phases of the menstrual cycle. No group differences in cold pain tolerance, TS, or conditioned pain modulation were evident at any phase of the menstrual cycle. These data suggest some evidence of central sensitization in young women with PD, although no evidence of enhanced excitatory or deficient inhibitory mechanisms were observed. Future research should focus on identifying other potential phenotypes for PD to determine those at risk of developing other pain problems.