Endometrial expression of vasopressin, oxytocin and their receptors in patients with primary dysmenorrhoea and healthy volunteers at ovulation

Exploration of new models for primary dysmenorrhea treatment: low-power visible-light-activated photodynamic therapy and oral contraceptives

Background

Primary dysmenorrhea (PD) is one of the most common reasons that affect the life quality of women during childbearing age. This research aims to explore the efficacy and curative effect characteristics of oral contraceptives and low-power visible-light-activated photodynamic therapy (PDT). Besides investigating the possible mechanism of PDT, we expected to find a treatment model with better efficacy and fewer side effects.

Method

It was a multicenter, randomized, parallel-controlled study. Eligible participants were randomly assigned to three groups: placebo group, oral contraceptive (Marvelon) group, and the PDT group. They were treated continuously for three menstrual cycles and followed up for two cycles after treatment. The scores of the visual analog scale (VAS) and the concentration of pain-related small molecules in blood before and after treatment were recorded in each group, which can evaluate the therapeutic characteristics of different treatments.

Result

Both Marvelon and PDT were effective. The effect of Marvelon appears quickly which can significantly relieve symptoms at the beginning, while PDT shows a relatively slow role. There was no significant difference in the final efficacy two cycles after treatment. The therapeutic effect was achieved by reducing the concentrations of prostaglandin 2 (PGE2) and endothelin (ET) in the blood.

Conclusion

Marvelon and PDT are effective methods for the treatment of PD. The long-term efficacy of the two is similar, while the therapeutic characteristics and the side effects are different. Patients can choose the suitable way according to their individual needs.

Do contrasting socio-ecological conditions bring difference in premenstrual syndrome and its concomitants? A sedente-migrant comparative study from Eastern India

OBJECTIVES

We asked in our research whether the premenstrual syndrome (PMS) and its concomitants, differ between "sedente" and "migrant" populations hailing from the same ethnic group, owing to their living in contrasting socio-ecological conditions.

METHODS

A total of 501 Oraon adolescents (sedente: 200, migrant: 301) were studied. Data on PMS was reported retrospectively using a list of 29 standard symptoms. Principal component analysis (PCA) was applied on PMS. PCA, which resulted in six principal components (PC1 to PC6) were loaded with "behavioral and cognitive," "negative mood," "pain and fluid retention," "vestibular and breast tenderness," and "fatigue," and/or "gastrointestinal" symptoms. Step-wise hierarchical regression was applied using migration status (step 1), socio-demographic (step 2), menstrual (step 3), and nutritional and lifestyle variables (step 4) as concomitants for each principal component.

RESULTS

Significantly, a greater number of migrants reported PMS but of milder intensity, unlike the sedentes. Significant sedente-migrant differences were found in the concomitants for PMS. Multivariate analyses showed differential socio-demographic (occupational, educational and wealth status, religion), nutritional (dietary carbohydrate protein and fat, tea intake, body mass index, percent body fat, waist hip ratio, fat mass index), menstrual (age at menarche, cycle length, dysmenorrhoea) and anemic status of the sedentes and the migrants were significantly associated with PMS.

CONCLUSIONS

Sedente and migrant participants, despite hailing from the same ethnic group, sharply differed in the prevalence of PMS and its concomitants owing to their living in contrasting socio-ecological conditions.

The Association of Reproductive Hormones During the Menstrual Period with Primary Dysmenorrhea

Objective

This study aimed to investigate the association of reproductive hormones with primary dysmenorrhea in Chinese women.

Methods

A case-control study was conducted and patients with primary dysmenorrhea and non-dysmenorrhea participants were recruited. Oxytocin, PGF2α, vasopressin, estriol and estradiol were respectively measured in plasma collected three to five days after menstruation. Restricted cubic spline and multiple logistic regression models were adopted to analyze the association between hormones and primary dysmenorrhea.

Results

There were 604 participants enrolled in our study including 300 patients with primary dysmenorrhea. After adjustment for the potential confounders, oxytocin levels (Q3: OR (95% CI) = 0.50 (0.27~0.95) (p=0.035); Q4: 0.34 (0.17~0.66) (p=0.001)) and PGF2α levels (Q3: 0.45 (0.24~0.87) (p=0.017); Q4: 0.43 (0.22~0.84) (p=0.013)) were respectively associated with an decreased risk of primary dysmenorrhea, but estradiol (Q2: 2.18 (1.13~4.19) (p=0.020); Q3: 2.17 (1.12~4.19) (p=0.022)) and vasopressin (Q3: 2.88 (1.48~5.63) (p=0.002); Q4: 3.20 (1.65~6.22) (p<0.001)) with an increased risk of primary dysmenorrhea, respectively. Among patients with primary dysmenorrhea, the higher estriol level was associated with higher frequent dysmenorrhea (Q2: 3.12 (1.32~7.34) (p=0.009); Q3: 4.97 (2.08~11.85) (p<0.001)) and always dysmenorrhea (Q2: 2.51 (1.03~6.11) (p=0.041); Q3: 3.10 (1.25~7.73) (p=0.015)). Similarly, high estriol levels were associated with the higher degree of pain significantly only when hormone levels were at a high level (Q3: 2.06 (1.03~4.18) (p=0.043)).

Conclusion

Higher serum vasopressin and estradiol concentrations as well as lower oxytocin and PGF2α levels were associated with higher risk of primary dysmenorrhea. Estrogen showed a reverse U-shape association on the frequency and degree of pain among patients with primary dysmenorrhea.

Moxibustion for Primary Dysmenorrhea: An Adjuvant Therapy for Pain Relief

The latest spectrum of moxibustion disease shows that primary dysmenorrhea is a high-frequency symptom of moxibustion and that it is the dominant clinical disease. In the specific treatment methods, all types of moxibustion methods have been widely used, such as thermal, thunder fire, partitioned, and spreading moxibustion. Moxibustion plays a therapeutic role through its four mechanisms of action: heat, light, moxa smoke, and drug effects. The mechanism of moxibustion treatment for primary dysmenorrhea focuses on adjusting endocrine hormones, regulating immune function and neuro-related factors, and improving uterine microcirculation. In this study, based on the clinical evidence of different moxibustion methods for treating primary dysmenorrhea, the design model, intervention characteristics, and clinical outcomes were analyzed. Meanwhile, the brain effect mechanisms of different imaging methods were summarized from the perspective of neuroimaging. It was pointed out that the left anterior cingulate gyrus, left inferior parietal angular gyrus, and left superior gyrus may be the analgesic brain regions that regulate sensory, emotional, and cognitive aspects. Moreover, the neural circuits involved can be inferred: the frontal cortex-basal ganglia (the pea nucleus)-cerebral cortex, which mediates motivation and emotional drive, and the parietal lobe-basal ganglia-limbic lobe-frontal lobe, which is involved in neurotransmitter transport and emotional regulation and behavioral expression. There are still problems and deficiencies in studies on the mechanism of moxibustion treatment for primary dysmenorrhea. Studies should be strengthened on how moxibustion produces an effect. Attention should be paid to exploring how the spectrum range and peak in the light effect of moxibustion treat primary dysmenorrhea. Studies assessing the mechanisms of moxibustion treatment for primary dysmenorrhea should be conducted to provide an experimental basis and evidence-based medical evidence for clinical treatment.

A cohort study of dysmenorrhea and risk of low birth weight

OBJECTIVE

Little is known about the association between maternal history of dysmenorrhea and perinatal outcomes. The aim of this study was to investigate the association between maternal history of dysmenorrhea and low birth weight (LBW).

METHODS

A total of 6754 pregnant women were recruited from the ongoing prospective cohort study in Guangxi, China, in 2015-2018. Information on the maternal history of dysmenorrhea was obtained by questionnaires including visual analog scale (VAS) questions during the first antenatal care visit. The association of maternal history of dysmenorrhea and LBW was evaluated using logistic regression analyses adjusted for confounding factors (infant sex, maternal age, parity, pre-pregnancy body mass index (BMI) (kg/m²), gestational age, alcohol use during pregnancy, passive smoking, and occupational status).

RESULTS

Mothers with a history of dysmenorrhea were more likely to give birth to LBW infants (adjusted odds ratio (OR)=1.44; 95% confidence interval (CI): 1.12, 1.83). Among women with a history of dysmenorrhea, women ≥29 years old (adjusted OR 1.46; 95% CI 1.02, 2.10), multiparous (adjusted OR 1.59, 95% CI 1.12, 2.25), and women gave birth to female infant (adjusted OR = 1.53, 95% CI = 1.11, 2.11) had a higher risk of LBW.

CONCLUSIONS

As the first cohort study to investigate the association between maternal history of dysmenorrhea and LBW, our study shows that dysmenorrhea may increase the risk of LBW.

Primary Dysmenorrhea in Relation to Oxidative Stress and Antioxidant Status: A Systematic Review of Case-Control Studies

Primary dysmenorrhea is defined as painful menstrual cramps of uterine origin in the absence of pelvic pathology and is the most common gynecological disorder among women of reproductive age. The aim of this study was to systematically review case-control studies that have investigated the oxidative stress, antioxidant status, and inflammation markers among women with primary dysmenorrhea and controls. The study protocol was registered with PROSPERO (no. CRD42020183104). By searching PubMed and Scopus databases as well as reference lists, six case-control studies with fifteen eligible markers (seven oxidative stress, seven antioxidant status, one inflammation) were included in this review. The quality of the included studies was assessed as medium or high. The systematic review included 175 women with primary dysmenorrhea and 161 controls. The results indicate an elevated level of oxidative stress, especially of lipid peroxidation among dysmenorrheal women. For the antioxidant status, limited evidence was found for a lower status among primary dysmenorrhea women, and only one study examined one inflammation marker (hs-CRP), which makes it impossible for such a conclusion. To establish whether oxidative stress, antioxidant status or inflammation participate in the pathophysiology of primary dysmenorrhea, high-quality studies with larger study groups and clear case definitions are needed.

Inflammatory Markers in Dysmenorrhea and Therapeutic Options

Dysmenorrhea often significantly reduces the quality of women's life and is still an important public health problem. Despite numerous studies, the pathomechanism of dysmenorrhea is not fully understood. Previous research indicates the complexity of biochemical reactions between the endocrine, vascular, and immune systems. Prostaglandins play a major role in the pathomechanism of dysmenorrhea. In contrast, cytokines and other proinflammatory factors in primary dysmenorrhea are less studied. In addition to the applied pharmacotherapy, more and more studies proving the effectiveness of non-pharmacological methods appear. Therefore, the present work contains a review of the latest research concerning factors involved in dysmenorrhea, as well as therapeutic options. In the literature search, authors used online databases, PubMed, and clinitrials.gov and browsed through individual gynecology, physiotherapy journals and books.

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.

How to Understand the Complexity of Endometriosis-Related Pain

Pain is the most important symptom in patients with endometriosis, and its management is truly challenging. Due to the different localization of the endometriotic lesions in the pelvis, patients suffer from visceral and somatic pain or both at the same time. There are specific and unspecific symptoms characterized by endometriosis. Specific symptoms include dysmenorrhea, cyclic and acyclic pelvic pain, dyschezia, dysuria and dyspareunia. There is also a wide range of unspecific symptoms, such as unspecific bowel and bladder complaints, the emission of pain in the legs, vegetative concomitants like vomiting, emesis, gastric disorders, headaches, dizziness, painful ovulation, irregular pelvic pain, lower back pain, chronic fatigue. These symptoms can be both cyclic and acyclic, and in most cases, they are permanent.

Visceral and somatic pain are completely different pain subtypes and can therefore be an explanation for the wide variety of symptoms. The close interaction between visceral sensory nerve fibers and the autonomic ganglia explain the high rate of concomitant vegetative reactions, such as vomiting and orthostatic dysregulation. In general, pain generation is a complex interplay of peripheral and central sensitization mechanisms. Accordingly, the pain produced in endometriotic lesions is the result of mediating substances, nerve fibers, cytokine-releasing immune cells and macrophages synthesis. These interactions seem to stimulate the neurogenic inflammatory process and sensitization of the peripheral nerves.

Furthermore, the disruption of the input on the level of the spinal cord and the recognition of the pain in the brain may lead to exaggerated responses known as central hyperalgesia. Hormones and psychological factors influence the pain sensation and make the status of each patient very individual. Consequently, the involvement of professional pain management along with an implementation of pain-coping strategies in the patient's everyday life are obligatory in chronic pain situations. An additional osteopathic treatment with a manual resolve of muscle blockades to avoid secondary “pain intensifying” changes of the pelvic floor (tension) or malposition through relieving posture, is also recommended.

Pain management in patients with endometriosis is very complex and requires an individual treatment strategy for each patient to avoid unnecessary surgical procedures. This information proves that it is hard to break the cycle of pain when chronic pain syndrome is already apparent.

Serum heme oxygenase-1 levels in patients with primary dysmenorrhea

PURPOSE

Primary dysmenorrhea effects the life-quality of women negatively. The aim of this study was to evaluate heme oxygenase-1 (HO1) activity together with malondialdehyde (MDA) and nitric oxide (NO) levels in patients with primary dysmenorrhea.

METHODS

A total of 28 nulliparous women with the diagnosis of primary dysmenorrhea and 26 healthy controls were included in this study. On the first day of menstruation, all patients underwent ultrasound examination to exclude pelvic pathology and the visual analogue scale was applied to patients. Patient's visual analogue scale (VAS) scores, age, body mass index (BMI), menstrual cycle length (day), length of bleeding (day) were recorded. In the same day, fasting blood samples were taken from each patient for biochemical analysis.

RESULTS

Serum MDA, NO and HO1 levels were found to be higher in women with primary dysmenorrhea compared to healthy controls (p = 0.012, p = 0.009, p < 0.001, respectively). There were no correlation among serum levels of HO1, NO and MDA, age, BMI, cycle length, pain score and menses duration in both groups. In Pearson's correlation analysis, positive correlation was found between HO1 levels with the NO levels (r = 0.316, p < 0.05) and VAS scores (r = 0.520, p < 0.01). Also, positive correlation was found between MDA levels and VAS scores (r = 0.327, p < 0.05).

CONCLUSIONS

Serum HO1, NO and MDA levels increase in patients with primary dysmenorrhea. Antioxidant support might be helpful to reduce pain severity in primary dysmenorrhea.

Reference ranges for uterine artery pulsatility index during the menstrual cycle: a cross-sectional study

BACKGROUND

Cyclic endometrial neoangiogenesis contributes to changes in local vascular patterns and is amenable to non-invasive assessment with Doppler sonography. We hypothesize that the uterine artery (UtA) impedance, measured by its pulsatility index (PI), exhibits a regular pattern during the normal menstrual cycle. Therefore, the main study objective was to derive normative new day-cycle-based reference ranges for the UtA-PI during the entire cycle from days 1 to 34 according to the isolated time effect and potential confounders such as age and parity.

METHODS

From January 2009 to December 2012, a cross-sectional study of 1,821 healthy women undergoing routine gynaecological ultrasound was performed. The Doppler flow of the right and left UtA-PI was studied transvaginally by colour and pulsed Doppler imaging. The mean right and left values and the presence or absence of a bilateral protodiastolic notch were recorded. Reference intervals for the PI according to the cycle day were generated by classical linear regression.

RESULTS

The majority of patients (97.5%) presented unilateral or bilateral UtA notches. The crude 5th, 50th, and 95th reference percentile curves of the UtA-PI at 1-34 days of the normal menstrual cycle were derived. In all curves, a progressive significant decrease occurred during the first 13 days, followed by an increase and recovery in the UtA-PI. The adjusted 5th, 50th, and 95th reference percentile curves for the effects of age and parity were also obtained. These two conditions generated an approximately identical UtA-PI pattern during the cycle, except with small but significant reductions at the temporal extremes.

CONCLUSIONS

The median, 5th, and the 95th percentiles of the UtA-PI decrease during the first third of the menstrual cycle and recover to their initial values during the last two thirds of the cycle. The rates of decrease and recovery depend significantly on age and parity.

Biomarkers of primary dysmenorrhea and herbal formula intervention: an exploratory metabonomics study of blood plasma and urine

Primary dysmenorrhea (PDM), a common clinical endocrine disorder affecting young women, is associated with endocrinopathy and metabolic abnormalities. Although some physiological and pathological function parameters have been investigated, little information about the changes of small metabolites in biofluids has been reported, which may cause poor diagnosis and treatment for PDM. The Xiang-Fu-Si-Wu Formula (XFSWF) is a Chinese herbal formula used to treat PDM for hundreds of years. The aim of this study was to establish the metabolic profile of PDM and investigate the action mechanism of XFSWF effect. In this cross-sectional study of 25 patients with PDM and 12 healthy controls, contents of small molecular endogenous metabolites in blood plasma and urine samples were measured by ultra performance liquid chromatography (UPLC) coupled with quadrupole-time-of-flight mass spectrometry (QTOF/MS) and triple quadrupole mass spectrometry (QqQ/MS) based techniques and analyzed by multivariate statistical methods. The levels of LPCs including lypso (16 : 1), lysoPC(20 : 4), lysoPC(18 : 2), lysoPC(16 : 0), lysoPC(18 : 1), lysoPC(10 : 1), estrone, 17-hydroxyprogesterone, myristoylglycine and palmitoylglycine increased significantly (p < 0.05) in PDM, while the levels of phytosphingosine, dihydrocortisol and sphingosine decreased significantly (p < 0.05) compared with the healthy controls. These significant perturbations are involved in glycerophospholipid metabolism and sphingolipid metabolism, as well as steroid hormone biosynthesis. The metabolic deviations recovered to the normal level after XFSWF intervention. The results demonstrated that biofluids metabonomics was a powerful tool in clinical diagnosis and treatment of PDM for providing information on changes in metabolites and neural, endocrinal and immune pathways. XFSWF can be used for the treatment of PDM cases, especially for those adolescents who do not desire a contraceptive method, to reduce the risk of secondary dysmenorrhea.

A double-blind, randomised, crossover study of two doses of a single-tablet combination of ibuprofen/paracetamol and placebo for primary dysmenorrhoea

OBJECTIVES

Efficacy of pain relief may potentially be enhanced by combining two or more analgesics with different mechanisms of action. The objective of this study was to assess the efficacy and tolerability of a novel single-tablet combination of ibuprofen and paracetamol compared with placebo in females experiencing moderate-to-severe pain due to primary dysmenorrhoea, a prevalent, recurrent condition characterised by pain at the time of menses.

METHODS

This was a phase II/III, double-blind, randomised, cross-over, single-dose study in 94 women with moderate-to-severe dysmenorrhoea, examining the efficacy and tolerability of one or two tablets of a single-tablet combination of ibuprofen 200 mg/paracetamol 500 mg compared with placebo.

CLINICAL TRIAL REGISTRATION

ISRCTN42521357

RESULTS

Total pain relief over 6 hours post-dose (TOTPAR(0-6h)) was significantly greater following administration of two tablets of the single-tablet combination of ibuprofen 200 mg/paracetamol 500 mg compared with placebo (LS means: 2.35, 1.85, respectively; p = 0.0001) and approached significance for one tablet (LS mean: 2.10; p = 0.054). Statistically superior pain relief and reductions in pain intensity were achieved from 2 hours and 90 minutes post-dose, respectively, with the higher dose combination, and from 4 hours with the lower dose combination compared with placebo. Overall effectiveness (sum of pain intensity difference and pain relief score [SPRID] over 6 hours) were statistically superior to placebo for both one and two tablets of the ibuprofen/paracetamol combination (p = 0.0011 and p = 0.03, respectively). Both dose combinations were well-tolerated. Adverse events were minor and their frequency and nature did not differ with either treatment compared with placebo.

CONCLUSIONS

One or two tablets of a single-tablet combination of ibuprofen 200 mg/paracetamol 500 mg is well-tolerated and provides superior analgesic efficacy to placebo in patients with primary dysmenorrhoea.

Possible roles of oxytocin receptor and vasopressin-1α receptor in the pathomechanism of dysperistalsis and dysmenorrhea in patients with adenomyosis uteri

OBJECTIVE

To investigate the expression of oxytocin (OTR) and/or vasopressin (VP1αR) receptor in patients with and without adenomyosis uteri.

DESIGN

Retrospective nonrandomized study.

SETTING

University hospital endometriosis research center.

PATIENT(S)

Forty patients with histologically proven adenomyosis and 40 patients without adenomyosis who had undergone hysterectomy for dysmenorrhea, bleeding disorders, and fibroids.

INTERVENTION(S)

Immunohistochemical examination of both OTR and VP1αR expression in endometrium, myometrium, and adenomyotic lesions, and identification of smooth muscle cells using antibodies against OTR, VP1αR, and smooth muscle actin (sm-actin).

MAIN OUTCOME MEASURE(S)

The immunoreactive score (IRS) was used for expression of OTR, VP1αR, and sm-actin.

RESULT(S)

Expression of OTR in epithelial cells of adenomyotic lesions and surrounding myometrial cells was detectable. VP1αR was expressed only in myometrial cells and blood vessels. Using a specific anti-sm-actin antibody, another spindle cell population was characterized to represent smooth muscle cells which are in direct contact with the adenomyotic stroma. Compared with the unaffected myometrium, the surrounding adenomyosis-associated myometrium overexpressed OTR and showed changes in morphology. In the uteri of patients with adenomyosis, the junctional zone was often seen to be quite fissured.

CONCLUSION(S)

In addition to the specific expression of VP1αR, OTR expression and morphologic changes in the myometrial architecture of uteri having adenomyosis support the hypothesis that dysperistalsis plays an essential role in the development of endometriosis and dysmenorrhea. In the near future, specific inhibition of this receptor might yield a promising treatment for therapy.

Immunoreactivity of oxytocin receptor and transient receptor potential vanilloid type 1 and its correlation with dysmenorrhea in adenomyosis

OBJECTIVE

We sought to investigate the expression and localization of oxytocin receptor (OTR) and transient receptor potential vanilloid type 1 (TRPV1) in women with and without adenomyosis.

STUDY DESIGN

Ectopic and homologous eutopic endometrium from 50 women with adenomyosis and endometrium from 18 women without adenomyosis were used for immunohistochemical analysis of OTR and TRPV1. Microscopic evaluation assessed the presence and localization of OTR and TRPV1 throughout the menstrual cycle in both eutopic endometrial and endometriotic tissues of women with adenomyosis and compared them with normal endometrium.

RESULTS

Compared with normal endometrium, immunoreactivity of OTR and TRPV1 were significantly increased in ectopic endometrium. Both OTR and TRPV1 immunoreactivity were positively correlated with the severity of dysmenorrhea and found to be significant predicators for dysmenorrhea severity.

CONCLUSION

These findings suggest that OTR and TRPV1 may be involved in dysmenorrhea and its severity in adenomyosis and may be potential therapeutic targets.

Myometrial oxytocin receptor mRNA concentrations at preterm and term delivery - the influence of external oxytocin

The hormonal system for induction of term and preterm labour is not fully understood. Therefore, we investigated myometrial gene expressions for neurohypophyseal hormones and their receptors, prostaglandin F(2alpha) and ovarian steroid receptors in women delivered by Caesarean section. Myometrial tissue for real time PCR was collected from 39 women delivered at term before and after the onset of labour and preterm. Women delivered electively at term had significantly higher oxytocin receptor mRNA expressions (2.52 +/- 0.37 oxytocin receptor/actin; median +/- SEM) than those delivered with ongoing labour at term (1.01 +/- 0.34; p = 0.015) and those at preterm (1.08 +/- 0.25; p = 0.004). Sub-analyses revealed that the difference at term pregnancies solely was related to patients receiving oxytocin during labour (p = 0.007). These patients had higher oxytocin peptide mRNA levels than those without labour at term (p = 0.009). PGF(2alpha) receptor mRNA concentrations were 27.80 +/- 3.55, 11.46 +/- 2.87 and 19.54 +/- 5.52 PGF receptor/actin, respectively, for the groups. Women without labour at term had higher concentration than those with labour (p = 0.005). Our results suggest that oxytocin, its receptor and the PGF(2alpha) receptor are involved in the regulation of labour through a paracrine mechanism.

Reproductive hormones in plasma over the menstrual cycle in primary dysmenorrhea compared with healthy subjects

The pathogenesis of primary dysmenorrhea is still poorly understood. The objective of the present investigation was to study differences in plasma concentrations of reproductive hormones in women with primary dysmenorrhea vs. healthy controls. In a prospective, parallel-group study we determined the plasma concentrations of oxytocin, vasopressin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17beta-estradiol (17beta-E2), progesterone and prostaglandin F 2alpha metabolite (15-keto-13,14-dihydro-PGF 2alpha) over one menstrual cycle in eight women with primary dysmenorrhea and eight healthy volunteers. In dysmenorrheic women the plasma concentration of oxytocin was significantly higher at menstruation (p = 0.0084) and that of vasopressin significantly lower at ovulation (p = 0.0281) compared with healthy women. They had also higher FSH levels in the early follicular phase (p = 0.0087) and at menstruation (p = 0.0066) and the 17beta-E2 concentration was higher in the late follicular phase (p = 0.0449). No differences were seen for LH, progesterone and PGF 2alpha metabolite. The differences of oxytocin, vasopressin, FSH and 17beta-E2 concentrations found in plasma suggest an involvement of these hormones in mechanisms of primary dysmenorrhea. These mechanisms seem to be mainly regulated through the hypothalamus and pituitary. The influence of oxytocin on the non-pregnant uterus seems to be more important than earlier believed.