Inhibition of Uterine Contractions of Premature Labour with an Oxytocin Analogue (original) (raw)
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BJOG: An International Journal of Obstetrics and Gynaecology, 1987
A competitive inhibitor of the action of oxytocin on the uterus, 1 -deamino-2-D-Tyr-(OEt)-4-Thr-8-Orn-oxytocin, was studied for the first time in 13 patients with established, uncomplicated premature labour. Intravenous infusion of 1C100 ygimin of the analogue was given for 1-10 h and the effect was monitored by external cardiotocography. In all women an inhibition of uterine activity was observed. and in the majority of patients infused with 25 pggimin and a total dose of about 5 mg or more of the drug total inhibition of uterine contractions was achieved. There were no effects on the maternal and fetal pulse rates, nor were there any other side-effects. The results of this preliminary study support the concept of an increased concentration of uterine oxytocin receptors being aetiologically important in uncomplicated premature labour. They also suggest that the present oxytocin antagonist could be an interesting therapeutic alternative in the condition, primarily because of the marked selectivity of its effect.
Efficacy of low dose vs. high dose oxytocin regimen for induction of labour
International journal of clinical obstetrics and gynaecology, 2022
Background and Aim: Synthetic oxytocin is one of the most frequently used medications in obstetric care and the common routine for augmentation of labour. High dose oxytocin has high risk of excessive uterine contraction or tachysystole. Present research is an attempt to evaluate effectiveness of low dose versus high dose regimen for induction of labour. Material and Methods: A total of 200 antenatal patients who were admitted for induction of labour were enrolled in the study. All patients were randomised by block randomisation into two groups i.e. Group I and Group II, each consisting of 100 patients. A detailed history, thorough clinical examination and relevant investigations were done for all the women. Per vaginal examination was done to know the cervical status and the bishop score. High dose regimen was started with 4mu/min with increment of 4mu/min up to a maximum of 32mu/min and low dose regimen was started with 2mu/min with increment of 2mu/min up to a maximum of 32mu/min. Induction to delivery interval was the primary outcome. Secondary outcomes noted were rate of caesarean section, tachysytole with or without fetal distress, failed induction, maternal outcomes like need for instrumental vaginal delivery, PPH and choriamnionitis, neonatal outcomes like NICU admission, umbilical cord pH and apgar score. Results: Women induced with high dose oxytocin regimen had shorter induction delivery interval as compared to low dose oxytocin interval by 2 hours 9 minutes. The incidence of various maternal outcomes in the high dose and low dose oxytocin regimen were similar. The most common indications for LSCS in the two groups were fetal distress and failed induction. A special consideration is required for the incidence of tachysystole, which was more in high dose regimen as compared to low dose oxytocin regimen but the difference was not statistically significant. Conclusion: High dose oxytocin regimen can be considered for induction of labour as it has same effects as that of low dose regimen with lesser induction to delivery interval.
The pharmacokinetics of oxytocin as they apply to labor induction
American Journal of Obstetrics and Gynecology, 1996
Our purpose was to determine the relationship among plasma oxytocin levels, metabolic clearance rate of oxytocin, and uterine activity in gravid women undergoing labor induction. Ten women receiving oxytocin for labor induction and agreeing to participate had blood sampled before initiation of oxytocin and at different levels of uterine pressure. Samples were analyzed with 200 microliter extracts from 1 ml of plasma with an oxytocin radioimmunoassay. The intraassay coefficient of variation was < 3%. Sensitivity of the assay was 1.5 pg/ml. Pharmacokinetic parameters including plasma levels and metabolic clearance rates were calculated. Data were analyzed with the paired t test and linear and logistic regression. Mean oxytocin levels and metabolic clearance rates were 26.6 pg/ml and 7.97 ml/min. There was no correlation between changes in oxytocin level and metabolic clearance rate. Increases in infusion rates were correlated with increases in oxytocin levels (r = 0.71, p < 0.001). Cervical dilatation and uterine contraction pressures did not correlate with oxytocin levels. Peripheral plasma levels of oxytocin may not accurately reflect uterine activity or progress in labor. Plasma levels of oxytocin may merely reflect the rate of oxytocin infusion.
International Journal of Women's Health, 2020
Background: Oxytocin is used for initiating uterine contraction and preventing postpartum hemorrhage during caesarean delivery. Using a lower dosage of oxytocin may lower the risk of adverse effects while still being effective in stimulating initial uterine contraction. We aimed to compare the effectiveness and side effects of the standard 10 IU bolus of oxytocin with those of a 5 IU bolus during caesarean delivery. Patients and Methods: We enrolled women in a randomized, double-blind, study comparing intravenous injections of high-dose (10 IU) and low-dose (5 IU) oxytocin administered after clamping of the umbilical cord. The primary outcome was adequate uterine contraction within the first 3 mins after administration. Secondary outcomes included uterine tone, use of additional uterotonic agents, additional obstetrics procedures, and oxytocin-related adverse events. Results: A total of 155 women underwent randomization, with 78 in the low-dose group and 77 in the high-dose group. The proportion of women with adequate uterine contraction during the first 3 mins was 84.6% in the low-dose group and 77.9% in the high-dose group (relative risk, 1.09; 95% CI, 0.93 to 1.26). Methylergonovine maleate was used in 14.1% of cases in the low-dose group and 36.4% in the high-dose group (relative risk, 0.40; 95% CI, 0.22 to 0.73). The necessity for additional obstetric procedures, estimated blood loss >500 mL, neonatal outcomes, and oxytocinrelated adverse effects did not differ significantly between the two groups. Conclusion: The 5 IU bolus of oxytocin was noninferior to the standard 10 IU bolus of oxytocin for initiating adequate uterine contraction, required fewer additional uterotonic agents, and led to fewer oxytocin-related adverse events.
BMC Pregnancy and Childbirth
Background: Oxytocin is an effective drug for induction of labour, but is associated with serious adverse effects of which uterine tachysystole, fetal distress and the need of immediate delivery are the most common. Discontinuation of oxytocin once the active phase of labour is established could reduce the adverse effects. The objective is to investigate how the caesarean section rate is affected when oxytocin stimulation is discontinued in the active phase of labour compared to labours where oxytocin is continued. Methods: CONDISOX is a double-blind multicentre randomised controlled trial conducted at Danish and Dutch Departments of Obstetrics and Gynaecology. The first participant was recruited on April 8 2016. Based on a clinically relevant relative reduction in caesarean section rate of 7%, an alpha of 0.05, a beta of 80%, we aim for 1200 participating women (600 in each arm). The CONDISOX trial includes women at a gestational age of 37-42 complete weeks of pregnancy, who have uterine activity stimulated with oxytocin infusion for the induction of labour. Women are randomised when the active phase of labour becomes established, to study medication containing either oxytocin (continuous group) or placebo (discontinued group) infusion. Women are stratified by birth site, indication for oxytocin stimulation (induction of labour, prelabour rupture of membranes) and parity (nulliparous, parous +/− previous caesarean section). We will compare the primary outcome, caesarean section rate, in the two groups using a chi-square test with a p-value of 0.05. If superiority is not demonstrated, we have a pre-defined post hoc non-inferiority boundary (margin, delta) at 1.09. Secondary outcomes include duration of the active phase of labour, incidence of uterine tachysystole, postpartum haemorrhage, admission to the neonatal intensive care unit, Apgar score, umbilical arterial blood pH, and birth experience. Discussion: The high frequency of oxytocin use and the potential risks of both maternal and fetal adverse effects of oxytocin emphasise the need to determine the optimal oxytocin regime for induction of labour.
Iranian Journal of Nursing and Midwifery Research, 2011
BACKGROUND: Oxytocin is the most consumed medication in modern midwifery. The consumption of oxytocin in inducing and strengthening delivery in delivery wards requires an efficient method for making use of this medication with maximum effect and minimum side effects. In this regard, this study has been conducted aiming at comparing the effect of two methods of prescribing oxytocin in inducing delivery on the duration of stages. METHODS: The present study is of a clinical trial kind with three-blinded parties which was conducted in 2010 on 120 research volunteers who had the inclusion criteria. The samples were randomly assigned into two groups of control and experiment. The data collection means consisted of a questionnaire and a checklist. In order to analyze the data, the SPSS software, version 17, Student T-test and Chi-square test were used. RESULTS: There was no statistically significant difference between two groups regarding the duration of the first and the first stages and the active phase. The duration of the third stage of delivery was shorter than the group which had stopped using oxytocin at the active phase. There has been no significant difference between the mean of oxytocin dosage from the initiation of the delivery induction till the active phase. The mean of oxytocin dosage has been significantly different between two groups during all stages of delivery so much so that this rate has been lower in the experiment group CONCLUSIONS: The results of the data analysis show that the continuation of oxytocin after the active phase not only does not have any advantage regarding the shortening of duration of stages and its cutting but also it leads to a decrease in the consumption dosage of oxytocin in the active phase and the second stage of delivery and on the other hand leads to a decrease in the side effects of the medication on mother and infant.