Characterizing the utilization of doula support services among birthing people of color in the United States: a scoping review.

BACKGROUND: Birthing people of color experience disproportionately higher rates of infant and maternal mortality during pregnancy and birth compared to their white counterparts. The utilization of doula support services may lead to improvements in the birthing experiences of birthing people of color. Yet, the research in this area is sparse. Thus, the purpose of this review is to characterize the research on doula utilization among birthing people of color, identify gaps in the field, and provide recommendations for future research. METHODS: Utilizing PRISMA guidelines, we conducted a scoping review, searching PubMed, PsycINFO, CINAHL, and Google Scholar for peer-reviewed articles published between January 1, 2016, to July 3, 2022. RESULTS: Twenty-five articles met inclusion criteria. We identified the three themes characterizing included studies: (1) how doulas support (HDS) their clients, (2) doula support outcomes (DSO), and (3) considerations for implementing doula support services (CIDS). Despite doulas being described as agents of empowerment, and providing social support, education, and advocacy, birthing people of color reported low utilization of doula support services and findings regarding their effectiveness in improving birthing outcomes were mixed. CONCLUSIONS: While some studies suggest that doulas may offer important services to birthing people of color, doulas are largely under-utilized, with many birthing people reporting low knowledge of their potential roles during the pre- and post-partum periods. Moreover, few studies were designed to assess intervention effects, limiting our ability to draw firm conclusions. Birthing people of color are at elevated risk for maternal mortality. As such, interventions are needed to support this population and improve outcomes. Our review suggests that, while doulas have the potential to make important contributions to the birthing support team, they are underutilized, and intervention studies are needed to enable estimates of their true effectiveness.

[Behavior of the mare during parturition - a literature review]. / Verhalten der Stute in der Geburt ­ eine Literaturübersicht.

In horses, parturition is characterized by the fact that any delays may rapidly result in the death of the foal. Therefore, birth monitoring and the rapid detection of dystocia are of great importance. For this purpose, the differentiation between behavior associated with physiological parturition and activities related to difficult parturition is important. The aim of this publication is to present the physiological behavior of mares during parturition on the basis of a literature review. The behavior of mares in the opening phase of parturition is highly individual. In general, it is characterized by an increase in movement activity. In this phase of parturition, 13 different behaviors have been described (e. g. lying down and standing up, cessation of feed intake, local sweating, frequent defecation and urination). Mares show a more uniform pattern of behavior in the expulsion phase and the following phase of expulsion of the fetal membranes and placenta. More than 95% of mares give birth in the lateral position. A mare usually remains in recumbency for several minutes following the expulsion of the fetus. Immediately after standing up, the mare begins to intensely interact with the foal. The expulsion of the fetal membranes and the placenta usually takes place in a standing position. From a clinical point of view, it is important to give consideration to the difficulty in recognizing the opening phase of parturition due to the mares' individual behavior patterns.

In the Murine and Bovine Maternal Mammary Gland Signal Transducer and Activator of Transcription 3 is Activated in Clusters of Epithelial Cells around the Day of Birth.

Signal transducers and activators of transcription (STAT) proteins regulate mammary development. Here we investigate the expression of phosphorylated STAT3 (pSTAT3) in the mouse and cow around the day of birth. We present localised colocation analysis, applicable to other mammary studies requiring identification of spatially congregated events. We demonstrate that pSTAT3-positive events are multifocally clustered in a non-random and statistically significant fashion. Arginase-1 expressing cells, consistent with macrophages, exhibit distinct clustering within the periparturient mammary gland. These findings represent a new facet of mammary STAT3 biology, and point to the presence of mammary sub-microenvironments.

Impact of parity on prepartum activities and behaviour in dromedary camels under farm conditions.

This study was conducted to assess the disparities in camel activities such as eating, drinking, sitting, standing, and sleeping between primiparous and multiparous females before parturition using computer vision. Also, any extraordinary behaviours during the final 2 h before parturition and the necessary manual interventions were meticulously recorded. Five primiparous (age: 4.5-7 years) and 7 multiparous (age: 8-14 years; parity: 2.1 ± 1.5) dromedary camels, were included in this study. Pre-partum females were housed double in a parturition pen provided with two Reolink RLC-810A cameras and the data were collected and recorded for each female. Two primiparous and 1 multiparous female required assistance in pulling the calf from both forelimbs to complete their parturition (27.3%). The drinking and sleeping activities were similar in primiparous and multiparous females during the recorded 32 h leading up to calving. Only eating activity exhibited a longer period in primiparous females compared to multiparous females specifically during the 12-h before calving. Sitting activity was longer, and standing activity was shorter in multiparous than in primiparous females during the 24, 12, and 6 h before calving. All parturient camels, whether primiparous or multiparous, exhibited signs of distress. Some extraordinary behaviours were observed, such as two multiparous females attempting to deter their primiparous counterparts from eating. Additionally, three females displayed a distinctive standing position on their knees while their hind limbs were in a complete standing position for 3-5 min before transitioning to sitting or standing positions. Furthermore, one primiparous female stood while the head and forelimbs of the calf partially protruded from her vulva. In conclusion, the application of computer vision and deep learning technology proves valuable for observing prepartum camels under farm conditions, potentially reducing economic losses stemming from delayed human intervention in dystocia cases.

Comparison of behavioral and physiological changes in postpartum healthy and inflammatory diseased cows.

During parturition, cows often experience intense pain and stress, which increases the risk of inflammatory diseases. This study aimed to compare the postpartum health status between healthy cows and those diagnoses with inflammatory diseases by examining behavioral and heart rate (HR) variability (HRV) changes, to provide information before the onset of disease. Eight Holstein cows were used in this study. HR, parameters of HRV (low-frequency power: LF; high-frequency power: HF; LF/HF ratio, and total power) and time budget of individual maintenance behaviors (standing, recumbency, feeding, rumination while standing and lying, and sleep) were continuously recorded from 0 to 168 h postpartum. Milk and blood samples were collected daily. Cows were categorized as diseases based on the positive result of California mastitis test and/or serum haptoglobin concentration that exceeded 50 µg/ml after all blood samples have been collected. Compared to healthy individuals (n = 3), diseased cows (n = 5) exhibited higher HR, LF/HF, and lower total power (p < 0.05), suggesting the dominance of the sympathetic nervous system in cows with inflammatory diseases. Additionally, diseased cows showed an increased standing time budget and reduced recumbency (p < 0.05), which may be a behavioral strategy in response to discomfort from inflammation.

Exercise FITT-V during pregnancy: Association with birth outcomes.

BACKGROUND: Prenatal exercise improves birth outcomes, but research into exercise dose-response effects is limited. METHODS: This study is a retrospective, secondary analysis of pooled data from three blinded, prospective, randomized controlled trials. Prenatal exercise frequency, intensity, type, time, and volume (FITT-V) were assessed in supervised sessions throughout pregnancy. Gestational age (GA), neonatal resting heart rate (rHR), morphometrics (body circumferences, weight-to-length and ponderal index) Apgar and reflex scores, and placental measures were obtained at birth. Stepwise regressions and Pearson correlations determined associations between FITT-V and birth outcomes. RESULTS: Prenatal exercise frequency reduces ponderal index (R2 = 0.15, F = 2.76, p = .05) and increased total number of reflexes present at birth (R2 = 0.24, F = 7.89, p < .001), while exercise intensity was related to greater gestational age and birth length (R2 = 0.08, F = 3.14; R2 = 0.12, F = 3.86, respectively; both p = .04); exercise weekly volume was associated with shorter hospital stay (R2 = 0.24, F = 4.73, p = .01). Furthermore, exercise type was associated with placenta size (R2 = 0.47, F = 3.51, p = .01). CONCLUSIONS: Prenatal exercise is positively related to birth and placental outcomes in a dose-dependent manner.

Does the pregnancy-related adaptation of gait biomechanics after childbirth recover to its pre-pregnancy state?: A systematic review.

BACKGROUND: Although changes in the gait biomechanics during pregnancy are known to occur, it is unclear whether they return to their original state after childbirth. RESEARCH QUESTION: The objective of the current systematic review is to summarize existing literature reporting the biomechanical characteristics of gait in postpartum women and to identify knowledge gaps that calls for future investigations in this population. METHODS: Relevant articles were selected using MEDLINE (PubMed), Scopus (Elsevier), Embase (Elsevier), and Web of Science (Clarivate Analytics). Articles were included if they met the following criteria: They must (1) include postpartum women, (2) report measures related to three-dimensional (3D) kinematics and/or kinetics, (3) have been published after 1990, and (4) have been published in English. RESULTS AND SIGNIFICANCE: The current systematic review included a total of 14 articles, five of which compare the data from postpartum women with nulliparous women or pre-pregnancy data. We observed that gait biomechanics changes of postpartum women could persist for more than 5 years after the childbirth. This review provides novel viewpoints on the biomechanics of postpartum women's gait and recommendations for future studies to fully understand these changes and improve postpartum women's physical and mental wellbeing.

Sow serenity: automatic long-term measurement of lying behavior in crates and free-farrowing pens using 3D accelerometers.

Accelerometers are useful in analyzing lying behavior in farm animals. The effect of the farrowing system on sow lying behavior has been studied around parturition, but not long-term. In a natural environment, sows increase activity 14 d post parturition, which we expected to be also evident in housed sows when they can move freely. The objective of this study was (1) to validate the methodology to automatically measure sow lying bouts and duration with accelerometers and (2) to apply it to crated and free-farrowing sows 24-h pre-parturition until weaning. We used videos with manual behavior coding as the gold standard for validation and calculated the agreement with an intraclass correlation coefficient (ICC), which was 0.30 (95% CI: -0.10 to 0.64) for the number of lying bouts. When transitional sitting bouts were excluded from the video dataset, the ICC for lying bouts increased to 0.86 (95% CI: 0.40 to 0.95). For lying duration, the ICC was 0.93 (95% CI: 0.26 to 0.98). We evaluated the effects of housing, day relative to parturition, and time of day on lying using the accelerometer data and linear mixed models. In crated sows, the number of lying bouts increased toward parturition, peaking at about five bouts per 6 h, and decreased to almost zero bouts after parturition. Then, it increased again (P = 0.001). In free-farrowing sows, the number of lying bouts gradually decreased from a high level towards parturition and was lowest after parturition. It remained constant, as in the crated sows, until day 15, when the number of bouts increased to eight bouts on day 20 (P = 0.001). Sows in both systems were lying almost all of the time between 18:00 and 00:00 hours and on all days (P = 0.001). The crated sows showed a very similar pattern in the other three-quarters of the day with a reduced lying time before parturition, a peak after parturition, reduced lying time from days 5 to 20, and an increase again towards weaning (P = 0.001). Free-farrowing sows had a similar pattern to the crated sows from 00:00 to 06:00 hours, but without the reduction in lying time from days 5 to 20. They showed an increase in lying time toward parturition, which remained constant with a final decrease toward weaning, especially during the day (P = 0.001). This study proves the accuracy of accelerometer-based sow lying behavior classification and shows that free-farrowing systems benefit lactating sows around parturition but also towards weaning in the nest-leaving phase by facilitating activity.

We analyzed lying behavior of sows using sensors, focusing on crated versus free-farrowing sows from pre-parturition to weaning. Lying behavior varies in this time following the needs of the sow and her litter. In a natural environment, sows increase activity 14 d post parturition, which we expected to be also evident in housed sows when they are allowed to move freely. Validation with video data showed excellent agreement for duration and frequency of lying. In crated sows, the number of lying bouts peaked around parturition, decreased after parturition, and then gradually increased. In free-farrowing sows, lying down occurred less often before parturition, but increased by day 20 compared to crated sows. Both housing systems showed prolonged lying periods from 18:00 to 00:00 hours. Crated sows had reduced lying times before parturition and lied longest post-parturition, which decreased until day 5 and then increased toward weaning. Free-farrowing sows had similar nocturnal patterns but persistent lying times that increased prior to parturition and decreased prior to weaning. Overall, the study highlighted the accuracy of accelerometer-based lying behavior classification and showed that free-farrowing systems benefit lactating sows not only around parturition but also toward weaning, facilitating activity during the nest-leaving phase.

The hormonal control of parturition.

Parturition is a complex physiological process that must occur in a reliable manner and at an appropriate gestation stage to ensure a healthy newborn and mother. To this end, hormones that affect the function of the gravid uterus, especially progesterone (P4), 17ß-estradiol (E2), oxytocin (OT), and prostaglandins (PGs), play pivotal roles. P4 via the nuclear P4 receptor (PR) promotes uterine quiescence and for most of pregnancy exerts a dominant block to labor. Loss of the P4 block to parturition in association with a gain in prolabor actions of E2 are key transitions in the hormonal cascade leading to parturition. P4 withdrawal can occur through various mechanisms depending on species and physiological context. Parturition in most species involves inflammation within the uterine tissues and especially at the maternal-fetal interface. Local PGs and other inflammatory mediators may initiate parturition by inducing P4 withdrawal. Withdrawal of the P4 block is coordinated with increased E2 actions to enhance uterotonic signals mediated by OT and PGs to promote uterine contractions, cervix softening, and membrane rupture, i.e., labor. This review examines recent advances in research to understand the hormonal control of parturition, with focus on the roles of P4, E2, PGs, OT, inflammatory cytokines, and placental peptide hormones together with evolutionary biology of and implications for clinical management of human parturition.

Conductivity of mammary gland secretions is a sensitive and specific predictor of parturition in mares.

BACKGROUND: Accurate prediction of parturition is paramount to ensuring monitoring of delivery and preventing complications. Assessing the pH and electrolytes of the mammary gland secretions (MGS) helps detect impending parturition. As conductivity is related to electrolyte concentrations and pH, it could be a useful alternative for predicting impending parturition; however, this hypothesis warrants a critical assessment. OBJECTIVES: To assess the ability of conductivity, pH, and Brix in the MGS to predict parturition and to investigate their associations. STUDY DESIGN: Field study. METHODS: The MGS of periparturient mares (n = 241) was assessed daily for conductivity, pH, and Brix index from 320d until parturition. Receiving operating curve cut-off values for conductivity (≤4.8 mS/cm), pH (≤6.4), and Brix index (>23.6%) were used to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for predicting parturition in ≤24 h. RESULTS: Impending parturition was associated with a reduction in conductivity and pH (p < 0.05), and conductivity was strongly correlated with pH (r = 0.88) and Brix (r = -0.80) (p < 0.05). Sensitivity, specificity, PPV, and NPV for parturition in ≤24 h for conductivity (82%, 91%, 77%, and 92%, respectively), pH (79%, 84%, 81%, and 71%, respectively), and Brix (72%, 79%, 66%, and 83%, respectively) were determined separated and pairwise. Of interest, the sensitivity, specificity, PPV, and NPV, of combining conductivity and pH, were 80%, 95%, 90%, and 88%, respectively. Conductivity (≤4.8 mS/cm) presented the greatest odds ratio for predicting parturition in ≤24 h, and coupling it with pH (≤6.4 pH units) doubled its odds ratio (i.e., 25.4-62.3). MAIN LIMITATIONS: Field study. CONCLUSION: The conductivity of MGS is a sensitive and specific method to predict parturition. This is the first large-scale study showing that a combination of conductivity and pH is useful for predicting parturition in mares. The methods employed can likely apply to other settings with similar results.

Simulation of the Childbirth Process in LS-DYNA.

Childbirth or labor, as the final phase of a pregnancy, is a biomechanical process that delivers the fetus from the uterus. It mainly involves two important biological structures in the mother, the uterus-generating the pushing force on the fetus-and the pelvis (bony pelvis and pelvic floor muscles)-resisting the movement of the fetus. The existing computational models developed in this field that simulate the childbirth process have focused on either the uterine expulsion force or the resistive structures of the pelvis, not both. An FEM model including both structures as a system was developed in this paper to simulate the fetus delivery process in LS-DYNA. Uterine active contraction was driven by contractile fiber elements using the Hill material model. The passive portion of the uterus and pelvic floor muscles were modeled with Neo Hookean and Mooney-Rivlin materials, respectively. The bony pelvis was modeled as a rigid body. The fetus was divided into three components: the head, neck, and body. Three uterine active contraction cycles were modeled. The model system was validated based on multiple outputs from the model, including the stress distribution within the uterus, the maximum Von Mises and principal stress on the pelvic floor muscles, the duration of the second stage of the labor, and the movement of the fetus. The developed model system can be applied to investigate the effects of pathomechanics related to labor, such as pelvic floor disorders and brachial plexus injury.

Morphological examination of pelvic floor muscles in a rat model of vaginal delivery.

OBJECTIVE: This study investigated morphological changes in the composition of the pelvic floor muscles, degree of atrophy, and urethral function in a rat of simulated birth trauma induced by vaginal distension (VD) model. METHODS: Female Sprague-Dawley rats were classified into four groups: a sham group, and 1, 2, and 4 weeks post-VD (1 W, 2 W, and 4 W, respectively) groups. We measured the amplitude of urethral response to electrical stimulation (A-URE) to evaluate urethral function. After measuring the muscle wet weight of the pubococcygeus (Pcm) and iliococcygeus (Icm) muscles, histochemical staining was used to classify muscle fibers into Types I, IIa, and IIb, and the occupancy and cross-sectional area of each muscle fiber were determined. RESULTS: There were 24 Sprague-Dawley rats used. A-URE was significantly lower in the 1 W group versus the other groups. Muscle wet weight was significantly lower in the VD groups versus the sham group for Pcm. The cross-sectional area of Type I Pcm and Icm was significantly lower in the VD groups versus the sham group. Type I muscle fiber composition in Pcm was significantly lower in the VD groups versus the sham groupand lowest in the 2 W group. Type I muscle fiber composition in Icm was significantly lower in the 2 and 4 W groups versus the sham group. CONCLUSION: Muscle atrophy and changes in muscle composition in the pelvic floor muscles were observed even after improvements in urethral function. These results may provide insight into the pathogenesis of stress urinary incontinence after VD.

Identification of genetic variants and individual genes associated with postpartum hypocalcemia in Holstein cows.

Periparturient hypocalcemia is a complex metabolic disorder that occurs at the onset of lactation because of a sudden irreversible loss of Ca incorporated into colostrum and milk. Some cows are unable to quickly adapt to this demand and succumb to clinical hypocalcemia, commonly known as milk fever, whereas a larger proportion of cows develop subclinical hypocalcemia. The main goal of this study was to identify causative mutations and candidate genes affecting postpartum blood calcium concentration in Holstein cows. Data consisted of blood calcium concentration measured in 2513 Holstein cows on the first three days after parturition. All cows had genotypic information for 79 k SNP markers. Two consecutive rounds of imputation were performed: first, the 2513 Holstein cows were imputed from 79 k to 312 k SNP markers. This imputation was performed using a reference set of 17,131 proven Holstein bulls with 312 k SNP markers. Then, the 2513 Holstein cows were imputed from 312 k markers to whole-genome sequence data. This second round of imputation used 179 Holstein animals from the 1000 Bulls Genome Project as a reference set. Three alternative phenotypes were evaluated: (1) total calcium concentration in the first 24 h postpartum, (2) total calcium concentration in the first 72 h postpartum calculated as the area under the curve; and (3) the recovery of total calcium concentration calculated as the difference in total calcium concentration between 72 and 24 h. The identification of genetic variants associated with these traits was performed using a two-step mixed model-based approach implemented in the R package MixABEL. The most significant variants were located within or near genes involved in calcium homeostasis and vitamin D transport (GC), calcium and potassium channels (JPH3 and KCNK13), energy and lipid metabolism (CA5A, PRORP, and SREBP1), and immune response (IL12RB2 and CXCL8), among other functions. This work provides the foundation for the development of novel breeding and management tools for reducing the incidence of periparturient hypocalcemia in dairy cattle.

[Induction and endocrine control of parturition in domestic mammals - Part 2 - Species-specific aspects and their relevance to the applicability of birth induction procedures]. / Initiierung und endokrine Kontrolle der Geburt bei Haussäugetieren ­ Teil 2.

The endocrine regulation of birth is based on an intensive exchange of signals between fetus, placenta and mother. Apart from sheep, our knowledge of the underlying processes is still very incomplete. However, current observations suggest substantial species differences. Of critical importance for the onset of the final steps of the signaling cascade leading to active labor is "prepartum progesterone withdrawal," which is based on luteolysis (e. g., cattle, goat, buffalo, camelids, pig) or a breakdown in placental progestogen production (sheep, horse), depending on the relevant progestogen source in late pregnancy. Knowledge of birth-associated regulatory processes allows species-specific regulatory mechanisms to be mimicked for drug-based induction of labor. Furthermore, species-independent mechanisms such as the inhibition of progesterone receptors are available. In addition to efficacy, other aspects such as tolerability for dams and offspring as well as drug regulations must be taken into account when selecting active ingredients under practical conditions.

In silico prediction of maximum perineal muscle strain during vaginal delivery by design of experiment.

BACKGROUND AND OBJECTIVE: The prevalence of pelvic floor muscle injuries induced by childbirth is higher than 23 % in the general women population. Such injuries can lead to prolapses and other pathologies in future female life. Leveraging computational biomechanics, the study implements an advanced female pelvic floor model for computing the maximum pelvic muscle strain, which serves as an injury risk indicator. The design of experiment method, abbreviated as DoE, is used to compute the maximum strain for boundary values of bony pelvis dimensions, namely the anterior-posterior diameter (abbreviated as APD) and the transverse diameter (abbreviated as TD). This is done in combination with small, medium and large percentiles of fetal head circumference (abbreviated as HC). METHODS: We utilized a previously developed finite element model of a female pelvic floor, as a reference, and enhanced it with new features, including a more detailed tissue geometry and advanced constitutive material models. The APD and TD dimensions were sourced from the set of MRI of 64 nulliparous women. This data was used to estimate the boundary dimensions of the female bony pelvis, combining both small and large values of APD and TD. Together with the 10th and the 95th percentiles for HC, a three-dimensional domain was constructed to assess the maximum pelvic muscle strain. In boundary cases, the maximum pelvic muscle strain was computed across 8 full-factorial design models (each situated at one corner of the domain, thereby combining the minimum and the maximum values of APD, TD and HC). This was done to define a response surface that predicts the maximum pelvic muscle strain within the domain. The accuracy of this response surface prediction was validated using 15 additional intermediate design models. These models were placed at the center of the domain (1 point), the centres of the domain boundary surfaces (6 points), and midway along each domain boundary edge (8 points). RESULTS: The maximum strain results for 8 combinations of APD, TD, and HC were employed to construct a linear response surface as a function of APD, TD, and HC. Tests at an additional 19 domain points served to evaluate the efficiency of the response surface prediction. The response surface demonstrated strong predictability, with an absolute average error of 1.52 %, an absolute median error of 1.52 %, and an absolute maximum error of 11.11 %. HC emerged as the most influencing dimension, accounting for 16 % of influence. CONCLUSIONS: The reference finite element pelvic floor model was scaled to 8 full-factorial female-specific pelvic floor models, which represent the combination of boundary values for APD, TD, and HC. The maximum pelvic floor muscle strain from these 8 models was used to design a response surface. When implementing the DoE approach to construct the response, there was consistent predictability for the maximum perineal muscle strain, as validated by the additional 19 intermediate design models. As a result, the response surface methodology can serve as an initial predictor for potential childbirth-induced pelvic floor muscle injury.

[Initiation and endocrine control of parturition in domestic mammals - Part 1]. / Initiierung und endokrine Kontrolle der Geburt bei Haussäugetieren ­ Teil 1.

Endocrine regulation of parturition is based on an intense exchange of signals between the fetus, placenta and mother. Apart from sheep, our knowledge of the endocrine control of parturition is still very incomplete. However, current observations suggest significant differences between the species. For the maintenance of pregnancy, progesterone (P4) is the crucial superordinate regulatory factor, although in some species, such as the horse, functions of P4 are at least partially fulfilled by other progestogens. In general, prepartum P4 withdrawal is considered a prerequisite for the onset of physiological birth. In species with exclusive (dog) or predominant (e. g., cattle, goat, pig) luteal P4 at the end of gestation, luteolysis is the crucial event. In sheep, where P4 is of placental origin prior to parturition, the prepartum P4 decline is due to a switch in placental steroid metabolism. The mechanism of prepartum progestogen withdrawal in the mare is still largely unclear. In sheep, initiation of parturition proceeds from maturation of the fetal hypothalamic-pituitary-adrenal (HPA) axis, which leads to a steep prepartum rise in fetal cortisol concentrations stimulating the collapse of placental P4 production. In cattle, fetal cortisol probably triggers luteolysis via stimulation of placental prostaglandin secretion. In several other domestic mammalian species, there is also evidence that the initiation of parturition proceeds from maturation of the fetal HPA axis. However, the functional relationships between fetal cortisol and prepartum P4 withdrawal are largely unknown in nonruminant species.

Progesterone control of myometrial contractility.

During pregnancy, the primary function of the uterus is to be quiescent and not contract, which allows the growing fetus to develop and mature. A uterine muscle layer, myometrium, is composed of smooth muscle cells (SMCs). Before the onset of labor contractions, the uterine SMCs experience a complex biochemical and molecular transformation involving the expression of contraction-associated proteins. Labor is initiated when genes in SMCs are activated in response to a combination of hormonal, inflammatory and mechanical signals. In this review, we provide an overview of molecular mechanisms regulating the process of parturition in humans, focusing on the hormonal control of the myometrium, particularly the steroid hormone progesterone. The primary reason for discussing the regulation of myometrial contractility by progesterone is the importance of the clinical problem of preterm birth. It is thought that the hormonal mechanisms regulating premature uterine contractions represent an untimely triggering of the normal events occurring during term parturition. Yet, our knowledge of the complex and redundant hormonal pathways controlling uterine contractile activity leading to delivery of the neonate remains incomplete. Finally, we introduce recent animal studies using a novel class of drugs, Selective Progesterone Receptor Modulators, targeting progesterone signaling to prevent premature myometrial contractions.

Autonomic nervous system balance in parturient mares: Spontaneous vs induced delivery.

Delivery is not easily predictable in horses and the consequences of dystocia can be serious for both the mare and foal. An induction protocol with low doses of oxytocin has been reported as a safe procedure. This study investigates the effect of induced delivery on at-term mares' sympathetic-vagal balance. Fourteen mares were included and divided into two groups, one subjected to spontaneous delivery (SD), and one to induced delivery (ID). In both groups, an ECG was recorded using an elastic belt with integrated smart textile electrodes. The recording started before the delivery (Basal), continued close to delivery (Pre-delivery) and during delivery (Delivery), and ended after parturition (Placental expulsion). From the ECGs, Heart Rate Variability (HRV) parameters relating to time and frequency domains and non-linear analysis were extrapolated. The HRV analysis was performed both within the same group (IntraGA) and between the two groups (InterGA). In the present study, spontaneous and induced delivery did not appear to differ in autonomic nervous system functioning. In IntraGA analysis, both for SD and ID mares, delivery and placental expulsion periods were parasympathetic dominated since vagal-related HRV parameters increased. Moreover, no differences were found in InterGA comparison between SD and ID mares, except for the pre-delivery period of ID mares, during which both branches of the autonomic nervous system were activated. These results are in line with the literature on parasympathetic dominance during parturition and no change in Heart Rate Variability following exogenous oxytocin administration in parturient mares.

[Definition, incidence and causes of dystocia in horses - a review of the literature]. / Definition, Häufigkeit und Ursachen der Dystokie beim Pferd ­ eine Literaturübersicht.

In horses, birth is classified as dystocia when the process of parturition threatens to inflict damage onto the mare or the foal, when assistance is required to complete the process of parturition, or when there are temporal deviations in the physiological duration of the first and/or second parturition stages. In this, the duration of the second stage is an important indicator in identifying dystocia, as this phase is easily discernible by the mare's behavior. Equine dystocia is classified as an emergency with life-threatening consequences for mare and foal. A large degree of variation has been found in the reported incidence of dystocia. Stud farm surveys reported dystocia in 2-13% of all births, regardless of breed. Fetal malpositioning of the limbs and neck during parturition is described as the most common cause of dystocia in horses. The species-specific length of limbs and neck is considered to be the reason for this finding.