Initiation Of Uterine Contractions Research Articles

Outcomes and Associated Factors of Induction of Labor in East Gojjam Zone, Northwest Ethiopia: A Multicenter Cross-Sectional Study.

Induction of labor is the initiation of uterine contractions by artificial methods once the fetus has reached viability and prior to spontaneous onset of labor with the aim of achieving vaginal delivery. Although induction of labor is a critical life-saving intervention that potentially reduces adverse pregnancy outcomes, sometimes it has undesirable consequences for the health of the mother and/or the fetus. Hence, this study aimed to evaluate the outcomes and associated factors of labor induction. An institution-based cross-sectional study was conducted from February 25 to May 25, 2020, among women undergoing induction at East Gojjam zone public hospitals in northwest Ethiopia. A structured interviewer-administered questionnaire was used to collect data from a sample of 411 mothers who were selected using a systematic random sampling technique. Stata/se™ Version 14 statistical software was used to analyze the data. Multivariable binary logistic regression was used to determine the potential factors affecting successful labor induction. Adjusted odds ratios with their 95% CI intervals were used to declare the strength of the association, and a variable with p value <0.05 was considered to have statistical significance. The prevalence of successful induction of labor was 70.3% (65.6, 74.7). The favorable Bishop score ((CI 3.90, 1.63-9.29); p value = 0.002), the intermediate Bishop score ((CI 3.53, 2.15-5.82); p value = 0.001), labor induction using oxytocin with cervical ripening ((CI 2.60, 1.21-5.63); p value = 0.015), and urban residence ((CI 0.48, 0.30-0.78); p value = 0.003) were associated with successful induction of labor. These findings strongly suggest that cervical conditions are important determinants for the success of labor induction. Therefore, healthcare providers should confirm the favorability of the cervical status (using Bishop score) as a strict prerequisite before actual labor induction, and special consideration should be given to those pregnant women who reside in urban areas.

Comparison of Efficacy of Trans-Cervical Foleys Catheter and PGE2 Gel for Induction of Labour

Background: Induction of labour is initiation of uterine contractions before the onset in order to vaginally deliver the fetoplacental unit. Common reasons for induction of labour (IOL) are post-term and hypertensive disorders of pregnancy. Many women who undergo induction do not have a favourable cervix, so some methods of cervical ripening either pharmaceutical or mechanical are used. Aim &amp; Objective: To compare the effectiveness of the transcervical Foley catheter and the prostaglandin E2 (PGE2) gel for the induction of labour. Methodology: The clinical trial was conducted for a period of two years OBGY department of Bharati Vidyapeeth University, Pune. 196 pregnant women which included and randomly via block randomization divided into two groups. Group A had 98 women in whom the transcervical Foley catheter was inserted and Group B included 98 women in whom the PGE2 gel was inserted vaginally for IOL. Bishop’s score and duration from induction to onset of labour was calculated. Data analysis was done and appropriate statistical tests were used. Results: In Group A (37.8%) as well as in Group B (41.8%) most of the pregnancies were primigravida. The most common indication for induction in both groups was postdatism. The adjuvant therapy was required in 66.3% and 54.1% of women in Group A &amp; B respectively. Significant higher median values were observed in Bishop’s score at 12 hours as compared to 0 hour in both the groups. No significant association was observed between mode of induction and need of adjuvant therapy and induction to onset hours in both groups. Conclusion: The study shows that both Foley's catheter and PGE2 gel are equally effective in pre induction cervical ripening.

Towards an evidence-based approach to optimize the success of labour induction.

Induction of labour is a two-step process involving cervical ripening and the initiation of uterine contractions, with the goal of achieving vaginal birth. To optimize the chance of a safe and timely vaginal birth, the process of induction of labour should be evidence based and individualized to the given person and situation. In this study, we lay out a framework for how this should be done, emphasizing on careful clinical assessment and planning, flexibility in the strategy of induction, patience during the ripening and latent phases of labour, and thoughtful consideration regarding changing the strategy if active labour is not initially achieved. The goal of this review is to present the current evidence on this topic in the form of a user-friendly protocol that can be easily adapted to institutional practice.

Maternal serum cytokine levels in pregnancies complicated with threatened preterm labour

Objective: To investigate serum inflammatory markers in singleton gestations complicated with threatened preterm labour (TPL).Methods: Pregnant women complicated with TPL (n = 61) were recruited to measure maternal serum levels of a panel of cytokines and C-reactive protein and then compared to controls without TPL, matched for gestational age (n = 64) and term pregnancies in the prodromal phase of labour (PPL) (n = 31). In addition, baseline cytokine levels were compared among cases and controls according to the outcome.Results: Women with TPL displayed higher CRP and white blood counts levels together with lower granulocyte macrophage colony-stimulating factor (GMC-SF) compared to both controls without TPL and to term gestations in the PPL. Also, interleukin 10 (IL-10), IL-6, IL-7, IL-8 and tumour necrosis alpha (TNF-α) levels were found significantly higher in TPL cases as compared to controls without TPL and term women in the PLL. Baseline cytokine levels (except IL-10) were higher among TPL cases who later delivered preterm. TPL cases delivering preterm displayed lower GMC-SF levels as compared to those delivering at term. Multivariate analysis found that gestational age at birth positively correlated with cervical length and inversely with CRP, IL-6 and TNF-α levels (p < 0.0001).Conclusions: TPL and preterm birth were related to inflammatory changes in the maternal side that correlate with cervical shortening and the initiation of uterine contractions.

Intrauterine infection as a possible trigger for labor: the role of toll-like receptors and proinflammatory cytokines

Background: The mechanisms underlying the initiation of premature uterine contractions during pregnancy are not fully understood. It is now widely accepted that proinflammatory cytokines are key mediators of the inflammatory signaling pathways in term or preterm labor. However, the exact triggers for inflammationinduced labor remain to be identified. Method: We review the published literature and summarize the possible pathophysiological mechanisms underlying the initiation of uterine contractions with a particular emphasis on intrauterine infection. Result: Term and preterm labor are associated with inflammation-induced infiltration of leukocytes into the myometrium, cervix, decidua, and fetal membranes. During labor, peripheral leukocytes invade uterine tissues and secrete bactericidal mediators such as proinflammatory cytokines, resulting in initiation of uterine activity and labor. When these pathophysiological mechanisms occur too early in pregnancy, they may lead to preterm labor. The initiation of inflammatory cascades within the myometrium or intrauterine compartments must be tightly regulated to prevent premature activation of the inflammatory signals and to prevent premature uterine activation. Conclusion: Labor in humans and rodents is associated with inflammation and the increased uterine contractions during labor are regulated by a complex of signaling pathways between pro- and antiinflammatory cytokines and between mother and fetus. Labor can be triggered from different sources including maternal, fetal and general infection. Therefore it is vital for pregnant women to avoid infection-related pathology and seek medical advice immediately to avoid premature uterine contractions or perhaps abortion. Keywords: Cytokines, infection, intrauterine, labor, myometrium, TLRs, uterus

Advances in the role of oxytocin receptors in human parturition

Oxytocin (OT) is a neurohypophysial hormone which has been found to play a central role in the regulation of human parturition. The most established role of oxytocin/oxytocin receptor (OT/OTR) system in human parturition is the initiation of uterine contractions, however, recent evidence have demonstrated that it may have a more complex role including initiation of inflammation, regulation of miRNA expression, as well as mediation of other non-classical oxytocin actions via receptor crosstalk with other G protein-coupled receptors (GPCRs). In this review we highlight both established and newly emerging roles of OT/OTR system in human parturition and discuss the expanding potential for OTRs as pharmacological targets in the management of preterm labour.

Differential activity of the gelatinases (matrix metalloproteinases 2 and 9) in the fetal membranes and decidua, associated with labour.

Degradation of the extracellular matrix in fetal membranes has been implicated in the rupture of fetal membranes, the process of parturition and placental detachment from the decidua after parturition. In this study we assessed labour-associated changes in gelatinase activity in cultured human amnion, chorion and decidua, as well as in amniotic fluid. We found that in media conditioned by decidua, following the establishment of uterine contractions, matrix metalloproteinase-2 (MMP-2) activity is increased while the protein tissue inhibitors of matrix metalloproteinase-1 (TIMP-1) level is decreased. The formation of a 130 kDa gelatinase band was also significantly increased after contractions began. In media conditioned by chorion, the initiation of uterine contractions did not change MMP activity or TIMP-1 levels. However, an increase in MMP-9 activity and a decrease in TIMP-1 protein levels were observed following the establishment of uterine contractions in media conditioned by amnion. We suggest that this differential spatial regulation provides a form for modulatory hieratical activity of the MMPs in the onset of labour allowing rupture of the membranes while avoiding premature placental separation.

Amnion cell biosynthesis of interleukin-8: regulation by inflammatory cytokines.

The cellular constituents of the placenta are important participants in the recruitment and trafficking of inflammatory cells within the placenta. In infection-induced labor, gestational tissues synthesize and release a variety of inflammatory cytokines whose effects include increased prostaglandin biosynthesis and the initiation of uterine contractions. Interleukin-8 (IL-8), a potent neutrophil chemoattractant, has been recently described as being elevated in the amniotic fluid of mothers with chorioamnionitis. We investigated the biosynthesis of IL-8 by human amnion cells and its regulation by other inflammatory cytokines. Cultured amnion cells obtained from normal term placentae were found to produce IL-8 in response to pathophysiologic concentrations of interleukin 1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF-alpha). Treatment of amnion cells stimulated by IL-1 beta with cycloheximide resulted in increased IL-8 production, while incubation of IL-1 beta treated amnion cells with actinomycin D resulted in a concentration-dependent decrease in detectable amounts of IL-8. Northern blot analysis of cultured amnion cells stimulated with IL-1 beta demonstrated a rapid increase in IL-8 mRNA which peaked at 2-4 hr. These in vitro results suggest inflammation of gestational tissues in vivo may result in locally produced IL-8 and, in association with other inflammatory mediators, may be important in the pathophysiology of infection-induced labor.

Increased prostaglandin concentrations in the cervical mucus of pregnant women with bacterial vaginosis

Microorganisms associated with bacterial vaginosis are commonly recovered from the amniotic fluid and chorion-amnion of patients who deliver prematurely. Bacteria closely related to those causing bacterial vaginosis may play a role in the initiation of uterine contractions, ripening of the cervix and weakening of the fetal membranes by stimulating prostaglandin synthesis. In the present investigation, cervical mucus was collected by brush from early pregnant women with and without bacterial vaginosis. The concentrations of PGE 2, PGF 2 α and 6-keto- PGF 1 α were determined in the mucus samples by methyl oximation and then radioimmunoassay, utilizing antibodies raised against oximated prostaglandins. It was found that the concentration of PGE 2 and PGF 2 α was significantly higher in the mucus of women with bacterial vaginosis compared with healthy women. The concentration of 6-keto- PGF 1 α was similar in both study groups. All patients had been instructed to abstain from sexual intercourse for 24 hours before sampling. However, it may be that women with high concentrations in their mucus may have had intercourse anyway. However, it is fairly well possible that the significant differences in the PGE 2 and PGF 2 α values are causally related to the higher rate of preterm labor in women with the commonplace infection of bacterial vaginosis.

The role of bacterial vaginosis as a cause of amniotic fluid infection, chorioamnionitis and prematurity — a review

Antepartum bacterial vaginosis in pregnancy has been related to premature delivery, the recovery of microorganisms from amniotic fluid of women in premature labor with intact membranes, to histologic chorioamnionitis and to the recovery of microorganisms from the placenta or membranes. Microorganisms associated with bacterial vaginosis are commonly recovered from the amniotic fluid and chorioamnion of patients who deliver prematurely. In addition, bacterial vaginosis is associated with maternal infectious morbidity during labor and in the postpartum period. Very little is known of the pathophysiologic mechanisms by which bacterial vaginosis may cause preterm labor and/or premature rupture of the membranes. However, it is of interest to speculate on possible mechanisms. The high concentration of potentially pathogenic microorganisms in the vagina and cervix of pregnant women with bacterial vaginosis may increase the possibility of an ascending infection via the cervix, decidua, fetal membranes, maternal placenta, and amniotic fluid. Some of the bacteria associated with bacterial vaginosis such as Bacteroides sp. are particularly virulent. Certain bacteria produce enzymes that potentially could affect the fetal membranes or maternal deciduae. Bacteroides sp. and group B streptococcus produce proteases. Protease enzymes reduce the chorioamniotic membrane strength in vitro. It is even possible that a high concentration of bacteria in the lower genital tract could produce enough proteases to weaken the fetal membrane strength causing premature rupture of the membranes. Bacterial lipases could also produce tissue injury. Schwarz et al. demonstrated that lysosomes within fetal membrane cells contain phospholipase A2 in high concentrations. Phospholipase A2 is a precursor of prostaglandin synthesis and the destruction of lysosomes within deciduae or chorioamnion cells may induce prostaglandin synthesis resulting in uterine contractions. Bejar et al. found a high rate of phospholipase A2 production by Bacteroides sp., anaerobic streptococci, Fusobacterium sp., and G. vaginalis. Benett et al. demonstrated that bacterial products of group B streptococci, viridans streptococci, Escherichia coli and Bacteroides fragilis but not of Lactobacillus sp. increase the synthesis of prostaglandins in the membranes. Thus, selected bacteria, including some closely related to bacterial vaginosis may play a role in the initiation of uterine contractions by stimulating prostaglandin synthesis. In an alternative mechanism, either the release of prostaglandin in the membrane or uterine contraction could cause microbreaks of the membrane that allow bacterial colonization of the membrane.(ABSTRACT TRUNCATED AT 400 WORDS)

Plasma prostaglandin F2 alpha and plasma 13,14-dihydro-15-keto-prostaglandin F2 alpha levels in women during induction of labor with i.v. infusion of prostaglandin F2 alpha in relation to uterine contractions.

The concentrations of plasma PGF2 alpha and its main metabolite, 13,14-dihydro-15-keto-PGF2 alpha (PGFM) were measured in serial samples of blood collected in 10 pregnant women at term who were given iv infusions of low doses of PGF2 alpha for induction of labor. Six other women served as controls and were given saline infusions. Uterine contractions began with a mean latency of 62 min in the PGF2 alpha infused women, in controls uterine activity remained unchanged. Plasma PGFM levels had increased significantly 30 min after PGF2 alpha infusion began, rising thereafter in a dose dependent manner. Plasma PGF2 alpha also rose reaching a steady state at 2 hours. No significant changes were observed in the controls. The 6-h infusion resulted in delivery in 5 of the 10 women, in the 5 others the cervical scores increased only by 1.25 points on the average and further treatment was needed to achieve delivery, although prostanoid levels rose to similar levels in all. The data show that when uterine contractions are induced by systemic PGF2 alpha, the levels of PGFM are significantly raised. In spontaneous labor uterine contractions begin long before plasma PGFM rises. Thus, if endogenous PGF2 alpha generation is involved in the initiation of uterine contractions during spontaneous labor, it must be synthetized in the myometrium at quantities too low to raise the levels of circulating PGFM.

Initiation of uterine contractions by disopyramide during pregnancy.

DISOPYRAMIDE (Norpace), a new antiarrhythmic agent with electrophysiologic properties similar to quinidine and possessing anticholinergic activity,1 is effective in the suppression of ventricular a...

Plasma prostaglandin metabolites in human labor

To elucidate the role of prostaglandins in initiating uterine contractions we studied the concentrations of 13,14-dihydro- 15-keto-PGE2 (PGE2-M) and 13,14-dihydro- 15-keto-PGF2α (PGF2α-M) in peripheral plasma of pregnant patients. The concentrations of PGE2-M and PGF2α-M in pregnant patients at term not in labor were not significantly different from those at midpregnancy. Induction of labor at term pregnancy caused a significant rise of both PGE2-M and PGF2α-M. During spontaneous labor there were no significant minute-to-minute fluctuations of plasma PGE2-M and PGF2α-M and their concentrations were not different from those at oxytocin-induced labor. Initiation of uterine contractions and abortion at midpregnancy by the intra-amniotic infusion of hypertonic saline was not associated with any change in PGE2-M concentration and a rise in PGF2α-M was noted in only one of five patients. The vaginal administration of PGE2 and the intra-amniotic infusion of PGF2α were associated in each case with a significant rise of both prostaglandin metabolites. It is concluded that the rise of prostaglandin metabolites in peripheral plasma is secondary to the initiation of uterine contractions at term pregnancy. Such a rise is not usually observed after the initiation of uterine contractions by hypertonic saline at midpregnancy.

The Effect of Intra‐Amniotic Injection of Hypertonic Urea on Human Placental Lactogen (HPL) Secretion

Segal, S., Ben‐David, M., Anteby, S. O. and Polishuk, W. Z. (Depts. of Obstetrics &amp; Gynecology and Pharmacology, Hadassah Medical Center, Jerusalem, Israel). The effect of intra‐amniotic injection of hypertonic urea on human placental lactogen (HPL) secretion.Int J Gynaecol Obstet 13: 193–196, 1975.Serum human placental lactogen (HPL) levels were studied in 27 women with normal pregnancies in their second trimester in whom abortion was induced by intra‐amniotic (IA) hypertonic urea. The levels of HPL remained stable during the procedure and up to the delivery of the placenta. The condition of the fetus (dead or alive) or the injection‐abortion interval did not affect HPL levels. It is thus concluded that HPL secretion is not impaired by the hypertonic urea, that it plays no role in initiation of uterine contractions, and whatever damage induced by the hypertonic urea solution does not affect HPL activity.