The phenomenon of reversible myometrial dysfunction and delayed rehabilitation of uterine contractive ability

The author introduces the conception o f potentially reversible myometrial dysfunction with unaffected main physiological function o f myometrium (viability o f myometrium). This dysfunction is connected with the disturbances o f uterine haemodynamics. The phenomenon o f reversible myometrial dysfunction reflects the process o f prolonged decreased contractile ability o f the uterus.The therapy o f reversible myometrial dysfunction phenomenon should be directed to blood flow restoration under the conditions o f uterine hypoperfusion.The special treatment is not required fo r myometrium with reserved main physiological functions (tonus, excitability) because restoration o f myometrial contractile ability improves spontaneously in case o f blood flow restoration.With the aim o f prophylaxis o f myometrial dysfunction and delayed rehabilitation o f the uterine contractile function administration o f Ca antagonists, beta-adrenomymetics, antioxidants and preparations, which improve myometrial metabolic processes, is recommended before the expected delivery.

Preterm Labor and Treatment Efficacy-Safety

With medical sciences on the verge of advancement, preterm labor still remains a bothersome issue in modern obstetrics. A few therapeutic agents that suppress uterine contractile activity have gained success up to some extent. Tocolytics are medications used to suppress premature labor. These drugs can decrease the strength and frequency of uterine contractions and help in delay the onset of labor but are not able to prolong pregnancy to full-term. Presently, the choice of a best tocolytic drug remains debatable. This review discusses efficacy and safety of various useful agents which have been used so far. Further clinical trials are required to select an effective, and most importantly, safe therapy for the threatened preterm labor.

Abnormal labor as a medical and social issue

Abnormal labor is a main cause of obstetric and perinatal complications. Impaired uterine contraction during childbirth is accompanied by an increase in the risk of fetal asphyxia, obstetric bleeding and postpartum inflammatory diseases. The frequency of diagnosed abnormal uterine contractile activity is 10-25%, which, along with the high need for operative delivery, allows for considering abnormal labor as one of the main medical and social issues of the present time. The aim of this study was to consider abnormal labor as a medical and social problem. This was achieved by using an analytical method including carrying out a detailed systematic analysis of modern domestic and foreign literature on abnormal labor. The study used databases such as eLIBRARY.RU, Scopus, PubMed, MEDLINE, ScienceDirect, and Cochrane Library from the creation until July 2021. Abnormal labor is an important medical and social issue that requires the active development of methods to predict and prevent not only violations of uterine contractility, but also their complications.

Impact of Dorsal Root Ganglia Cryoextract on Histological Steatures in Dices and Contractility of Uterus in Differently Aged Rats

To date, the number of women giving birth to their first child in late reproductive age is increasing around the world. This stipulates a need in designing the new approaches to restore the uterine contractile activity. In this paper, the histological features of uterus and its contractile activity have been experimentally studied in differently aged rats after the dorsal root ganglia cryoextract (DRGCE) administration. The cryoextract was derived from dorsal root ganglia of neonatal piglets by three-fold freezing down to –196°C in saline, followed by thawing at room temperature, homogenization and centrifugation. Here, we used the female rats of reproductive age (RA, 6-month-old) and those of late reproductive age (LRA, 14-month-old). Animals of both age groups received intraperitoneally either DRGCE (experimental groups) or saline (control groups) for 9 days by 0.2 ml. To days 28–29 after administration beginning the animals were sacrificed and the uterine fragments were taken for histological examination and study of oxytocin (OT)-induced uterine contractile activity (UCA). The strength of OT-induced uterine isometric contraction was found to decrease by 28.6% in LRA rats vs. the RA ones. The DRGCE administration to LRA rats increased the UCA indices, namely the contractile frequency, contractile amplitude and strength of isometric contraction augmented by 25, 9.8 and 30% respectively, as compared with the group of the same age without DRGCE introduction. This effect was observed on the background normal uterine histological structure and unchanged myometrial thickness.

Uterine contractile activity and fetal outcome in rats treated with vitamin C during late gestational variable stress exposure

Objectives Stress responses vary throughout pregnancy and impact of late gestational variable stress (LGVS) with vitamin C supplementation on uterine contractility is barely explored. This study investigates fetal weight outcome and in-vitro uterine contractile responses to pharmacological agents during LGVS exposure. Methods Twenty four nulliparous pregnant rats were divided into four groups of six. During gestation days 10–19, groups 1 & 2 received normal saline and vitamin C (10 mg/kg) respectively. Groups 3 and 4 were exposed to stress (sleep deprivation, predator exposure, immobility, rapid cage changes, noise, and foreign object) with group 4 concurrently supplemented with vitamin C (10 mg/kg). Serum cortisol, oxidative bio-markers, fetal weights and in-vitro contractile responses of excised uterine tissue to acetylcholine (Ach), oxytocin, calcium chloride (CaCl2), potassium chloride (KCl), diclofenac, and magnesium ions were determined. Results Malondialdehyde activity and cortisol were significantly increased in variable stress only exposed group when compared with control and vitamin C supplemented groups. Fetal body weights, superoxide dismutase and catalase activity were significantly reduced in variable stress only exposed group. Significantly impaired contractile responses to Ach, CaCl2 & KCl in variable stress only exposed group were modulated in vitamin C supplemented groups. Impaired contractile response to oxytocin was however not reversed. Relaxation responses to diclofenac and magnesium ions were statistically unaltered across groups. Conclusions Impaired fetal weights and uterine contractile activity to Ach, CaCl2 and KCl during LGVS was modulated by vitamin C supplementation. Impaired oxytocin contractile activity was however unreversed.

Critical role of V1a vasopressin receptor in murine parturition

The precise mechanisms of the reproductive physiological processes, such as labor initiation, are poorly understood. Oxytocin (OT) is one of the well-known uterotonics and is clinically adopted as a medication to facilitate childbirth. Vasopressin (VP), a posterior pituitary hormone similar to OT, has also been proposed to be involved in the reproductive physiology. In this study, we found that a total deficiency of V1a receptor subtype (V1aR) in mice resulted in a reduced number of pups, delayed labor initiation, and increased post-delivery hemorrhage compared with those in wild-type mice. Among the VP receptor subtypes, only V1aR was found to be expressed in the murine uterus and its distribution pattern was different from that of the oxytocin receptor (OTR); V1aR expression was mainly distributed in the circular myometrium, whereas OTR was strongly expressed in both the circular and longitudinal myometrium. The maximum contractile force of the circular myometrium, induced by VP or OT, was attenuated in the pregnant uterus of Avpr1a-deficient mice. Contrarily, while OT expression was decreased in the Avpr1a-deficient uterus, OTR expression was significantly increased. These results suggest that V1aR deficiency not only reduces the uterine contractile force but also perturbs the expression of genes responsible for the reproductive physiology. Therefore, V1aR is necessary to exert the maximum contraction of the circular myometrium to deliver pups. This study revealed an important role of V1aR in physiological contraction and term parturition in mice.

Possibilities for predicting abnormal labor at the present stage

Hypothesis/aims of study. Labor abnormalities can lead to dangerous complications for both the mother and the fetus. There are currently no effective ways to prevent abnormal uterine contractile activity. Therefore, the timeliness of diagnosis, which largely determines labor outcome, depends on the effectiveness of assessing the likelihood of the development of abnormal labor. The aim of this study was to examine the possibilities for predicting abnormal labor progression at the present stage of the development of science. Study design, materials and methods. A systematic analysis and synthesis of the literature data presented by domestic and foreign authors in the period from 1985 to 2020. Conclusion. A comprehensive approach to assessing the likelihood of the development of abnormal labor will optimize the tactics of labor management, which in the long-term will reduce the frequency of surgical delivery.

Экспериментальные модели сократительной активности миометрия

Сократительная деятельность матки до настоящего времени остается актуальным вопросом фундаментальных исследований, поскольку отсутствуют единые представления о биомеханике маточного сокращения, необходимые для профилактики родового и акушерского травматизма. Цель работы - оценка ограничений и возможностей экспериментальных моделей, предназначенных для изучения сократительной активности миометрия. Методика. Основными экспериментальными подходами к изучению сократительной активности матки являлись исследования in vitro, in situ, in vivo, in silico, а также их сочетание. Результаты. В статье рассмотрены исследования, в которых использованы различные сочетания экспериментальных подходов, обсуждаются результаты, полученные при моделировании в экспериментах, обсуждаются результаты изучения синхронизации сокращения отделов матки на различных моделях, а также результаты исследования пейсмейкерной активности миометрия и возможность экстраполяции полученных данных на человека. В связи с активным развитием компьютерных технологий в статье поднимается вопрос об их использовании в моделировании сократительной активности матки человека. Заключение. Делается заключение, что комплексный подход, включающий электромиографические, биохимические и морфологические исследования в хроническом эксперименте, является наиболее адекватным для изучения сократительной активности миометрия и функционального состояния нормально развитых и отставших в развитии плодов, что позволит разработать комплексные методы профилактики родового и акушерского травматизма.Uterine contractile activity remains an important issue of fundamental research as there is no single view of the biomechanics of uterine contraction necessary for the prevention of parturition and obstetric trauma until now. The aim of the review was to assess advantages and limitations of experimental models described in the literature for study uterine contractile activity. At the present time main experimental approaches for study myometrium contractile activity are research in vitro, in situ, in vivo, in silico and the their combinations. The literature presents experimental approaches, different models of uterine contractions synchronization and study of myometrium pacemaker activity. Due to active development of computer technologies there is a need to model human uterine contractile activity with a simplified anatomy. The authors propose that combination of electromyographic, biochemical and morphological methods in chronic experiment is the most correct and appropriate direction for the assessment of the myometrium contractile activity and functional state of normally developed and growth restricted fetuses.