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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Retrospective data collected from the medical records of 1040 low-risk nulliparous obstetric patients presenting for delivery in a general community hospital in Ireland and a comparable one in the United States showed a significantly higher rate of caesarean section for dystocia or abnormal labour in the American hospital--a discrepancy which was not easily explained by differences in patient characteristics (eg, maternal age, known risk factors, birthweight). Acceleration of labour with oxytocin was significantly more common in the Irish group, and average duration of labour was shorter. No advantage to the infant, as measured by the Apgar score, resulted from the greater use of caesarean section for dystocia.
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PMID:Caesarean section for dystocia: a comparison of practices in two countries. 288 Oct 91

Cephalopelvic disproportion has been identified as making an important contribution to the rising cesarean birth rate. O'Driscoll and colleagues in Dublin, Ireland, have suggested replacement of cephalopelvic disproportion by the term dystocia for failure of labor to progress and have defined two major subcategories: (1) true cephalopelvic disproportion, and (2) inefficient uterine action. A chart audit of reported indications for cesarean birth in a family practice residency population was done, and patients were classified using the O'Driscoll et al diagnostic criteria for dystocia. When reclassified, the percentage of cesarean births in this population for true cephalopelvic disproportion did not differ significantly from that reported from Dublin (6.1 as compared with 8.8), while the percentage done for inefficient uterine action was significantly greater (35.4 as compared with 4.2). This finding suggests there is a set of labors amenable to a management strategy that could result in a decrease in the cesarean birth rates if efficient uterine action is assured with adequate use of oxytocin.
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PMID:Diagnostic criteria and the management of dystocia. 319 87

Concentrations of plasma progesterone were similar to values reported in the literature except that a significant decrease in progesterone during the last day, but before parturition, was detected by systematic, high-intensity blood sampling. Mean concentrations of oestradiol-17 beta increased sharply and significantly, plateaued for 132.8 +/- 1.5 days (mean +/- s.e.m., N = 9), then declined sharply in each mare. There was obvious variation between the mares in when these increases and decreases in oestradiol-17 beta occurred, with the events being related closely to ambient photoperiod conditions rather than to the stage of pregnancy. Concentration of 13,14-dihydro-15-keto-prostaglandin F-2 alpha (PGFM) remained at low levels (less than 400 pg/ml) until Day 200 then increased to peak pregnancy levels (greater than 2000 pg/ml) by Day 300 and remained at this value until parturition. The concentrations of oxytocin remained basal (less than 15 microU/ml) throughout pregnancy and increased only at the beginning of the expulsive stage of labour. There was an increase, although not statistically significant, in the relative concentrations of oestradiol-17 beta to progesterone beginning 3 days before parturition, with the highest value of the ratio occurring at fetal delivery. Far more striking were acute changes in PGFM and oxytocin during parturition. Maximal concentrations of PGFM (approximately 30 ng/ml) and oxytocin (greater than 200 microU/ml) were measured between rupture of the chorioallantois and the completion of delivery. Closely timed samples from one animal showed that oxytocin increased (more than 10 standard deviations of the mean levels during late pregnancy for this animal) before any change in PGFM. In another dystocic mare, both oxytocin and PGFM peaked in the initial stages of delivery but only oxytocin remained elevated until the dystocia was remedied. The results suggest that an abrupt increase in oxytocin secretion precipitates the expulsive phase of parturition in mares.
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PMID:Variation in plasma concentrations of oestradiol-17 beta and their relationship to those of progesterone, 13,14-dihydro-15-keto-prostaglandin F-2 alpha and oxytocin across pregnancy and at parturition in pony mares. 319 83

There has been a fourfold increase in cesarean births in Canada in the last 20 years. The two main indications are dystocia and repeat cesarean section. Of all primary cesarean sections, about half are due to dystocia. This is largely confined to nulliparous women. Work from Ireland suggests that a policy of active management of labor may reduce dystocia. This involves a uniform policy of amniotomy once a diagnosis of labor is established, followed by oxytocin augmentation if labor is nonprogressive (less than 1 cm/hr). From October 1, 1985, to December 31, 1986, this policy was carried out on 552 consecutive normal nulliparous women in spontaneous labor at greater than or equal to 37 weeks' gestation with a single fetus in vertex presentation with no fetal distress. These results were compared with a control group of 533 similar nulliparous women delivered between January 1, 1984 and March 31, 1985. The cesarean section rate dropped to 4.3% from 13% (p less than 0.005) and the forceps delivery rate dropped to 19.4% from 29% (p less than 0.005). The duration of labor greater than 12 hours dropped to 7% from 20% (p less than 0.005). There was no increase in fetal morbidity or mortality.
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PMID:Active management of labor and operative delivery in nulliparous women. 334 3

This study was designed to investigate the possible benefits, in terms of obstetric and neonatal outcome, of a prolonged augmentation period with oxytocin in patients with dysfunctional first stage of labour. The majority of patients (65.5% of nulliparas and 83.8% of multiparas) responded with satisfactory progress within the first 4 hours of augmentation and the Caesarean section rate was low in this group (1.3%). In those with unsatisfactory progress during the first 4 hours of augmentation a further 4 hour period of augmentation resulted in vaginal delivery for 50.7% of nulliparas with primary dysfunctional labour and 33.3% of those with secondary arrest in labour. Corresponding figures for multiparas were 41.7% and 25.0%, respectively. The neonatal outcome was uniformly good. It is concluded that the management protocol presented for augmentation of labour seems to be a safe procedure and might reduce the rising Caesarean section rate for dystocia.
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PMID:Augmentation of labour--mode of delivery related to cervimetric progress. 345 67

This article has considered the subject of bony pelvic dystocia and soft tissue dystocia. Dystocia most often results from a combination of fetal and pelvic factors. However, on many occasions the size and shape of the pelvis is the initial problem, which encourages the fetus to take up a malposition such as occiput-posterior, and this in turn results in a dysfunctional contraction pattern that may or may not be corrected by oxytocin augmentation--a vicious circle that can only be broken by performance of a cesarean section. With minor degrees of pelvic dystocia, asynclitism and molding of the fetal head can often make a safe vaginal delivery possible. Clinically all pelvises can be categorized into adequate, questionable, and too small. The latter group is the least common and generally includes the congenitally or developmentally abnormal pelvises, and in most cases primary cesarean section should be the mode of delivery. In all other pelvises with a vertex presentation, a trial of labor is indicated because the fetal head is an excellent pelvimeter. With proper fetal monitoring with an intrauterine pressure catheter, with the use of a partograph to assist in the diagnosis of an active-phase arrest, followed by a cesarean section at the appropriate time, there is no increase in fetal or maternal morbidity. If the breech is the presenting part, then there are only two types of pelvis--very adequate and inadequate--and x-ray pelvimetry should be used to help in the classification.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Soft tissue and pelvic dystocia. 355 19

To clarify the origin of dystocia in bilaterally pelvic neurectomized (BPN) rats, the uterine activity during the periparturient period, and reflex straining movements in response to vaginal stimulation and cervical extensibility were monitored. The BPN rat displayed "stretching" movements and the regular continuous uterine activity with a similar onset and intensity to that in control rats (intact, sham-operated or unilateral pelvic neurectomized rats) on days 22 or 23 of gestation, but lacked the "straining" movements which precede each delivery of pups in controls so that parturition was prolonged. Dissection of rats revealed that an unborn fetus was retained in the expanded upper portion of the vaginal cavity. Vaginal distension induced contraction of the abdominal muscles and diaphragm and an inhibition of respiratory movements, resulting in an increase in intraabdominal pressure in urethane-anesthetized control rats. This reflex muscular contraction which reflects the straining movements in normal delivery may be called the fetus-expulsion reflex and does not occur in BPN rats. It differs from the fetus-ejection reflex (Ferguson reflex) which initiates oxytocin release. There was no difference in weight and distensibility of the uterine cervix between sham-operated and operated rats on day 22 of pregnancy. The results suggest that the main abnormality of delivery in BPN rats, a prolongation of the process of delivery, may be due to a lack of the fetus-expulsion reflex which plays a physiologic role in removing a fetus from the upper vaginal cavity against the resistance of the pelvic outlet.
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PMID:Pelvic neurectomy abolishes the fetus-expulsion reflex and induces dystocia in the rat. 356 66

We examined the risk of maternal obesity in 588 pregnant women weighing at least 113.6 kilograms (250 pounds) during pregnancy. Compared with a control group matched for age and parity, we found a significantly increased risk in the obese patient for gestational diabetes, hypertension, therapeutic induction, prolonged second stage of labor, oxytocin stimulation of labor, shoulder dystocia, infants weighing more than 4,000 grams and delivery after 42 weeks gestation. Certain operative complications were also more common in obese women undergoing cesarean section including estimated blood loss of more than 1,000 milliliters, operating time of more than two hours and wound infection postoperatively. These differences remained significant after controlling for appropriate confounding variables. We conclude that maternal obesity should be considered a high risk factor.
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PMID:Maternal obesity and pregnancy. 357 19

To summarize: Functional dystocia is easily diagnosed in laboring patients by lack of cervical dilatation for 2 hours in association with weak uterine contractions. If the membranes are intact, amniotomy should be performed. If cervical dilatation at a rate of at least 1 cm/h does not occur promptly, oxytocin should be begun. Efficient and safe use of oxytocin requires knowledge of its clinical pharmacologic characteristics: that the maximum level of a dose is not reached for approximately 40 minutes, that the blood level needed is a reflection of the sensitivity of the myometrium, and the blood level produced by a specific dose is a manifestation of the plasma clearance rate. While it has never been demonstrated that continuous electronic monitoring of the uterus and fetus with intermittent visits from professional personnel is better than palpation and auscultation performed by an educated attendant present continuously, the former practice is more common in the United States than the latter. If maximum use is to be made of the information provided by the uterine monitor, the data must be quantitated. When the patient's inadequate contractility fails to improve in response to the initial dose of 1 mU/m, the dose must be increased until some improvement is noted. Geometric incrementation should be limited to nulliparas in whom each dose of oxytocin is evaluated after a 40-minute infusion period.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The management of functional dystocia in the first stage of labor. 358 58

Experiments were carried out to investigate the effects of porcine relaxin on the course of gestation and delivery in the rat. Plasma relaxin was maintained at approximately 600 nmol/l from day 19 to day 23 of gestation by i.v. infusion from chronically implanted minipumps. Relaxin significantly (P less than 0.001) prolonged the length of gestation in 17 rats compared with controls, without causing dystocia or affecting the number of live births. Six rats gave birth during relaxin infusion. In these animals there was a significant (P less than 0.001) increase in the interval between successive deliveries compared with control animals, resulting in prolonged labour. The remaining 11 rats gave birth after the infusion was completed, when the interval between successive deliveries was significantly (P less than 0.025) shorter than controls. The results are consistent with the hypothesis that relaxin has a central action suppressing the release of oxytocin as well as a peripheral action on the myometrium and cervix.
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PMID:Effects of porcine relaxin on the length of gestation and duration of parturition in the rat. 370 Dec 47


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