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At least 19 recordsLinked to original sources

PubMed1991

Do biphasic uterine contractions imply poor uterine function?

In a retrospective study of 362 cardiotocographic recordings of primigravidae in labour we found 8% biphasic or coupled uterine contractions. In augmented labour, biphasic contractions occurred almost twice as often as in spontaneous and induced labour. The duration of labour complicated with biphasic contractions was increased significantly in all types of labour. Therefore biphasic contractions may reflect uneffective uterine function. Contrary to other studies, the appearance of biphasic contractions showed no correlation with epidural analgesia and the incidence of instrumental deliveries or caesarean sections was not increased.

Analgesia, Epidural↗

PubMed1976

A comparative study of uterine activity in labour induced with prostaglandin F2alpha or oxytocin and in spontaneous labour. I. Pattern of the uterine contractions.

The uterine contraction patterns and the changes in fetal heart rate (FHR) were studied in cardiotocographic recordings from 26 women in oxytocin-induced labour, 26 women in PGF2alpha-induced labour and 24 women during the later part of spontaneous labour. The contraction patterns and their effect on the FHR did not differ between the three groups. During the course of labour an increasing steepness of the upward slope of the contraction wave with increasing intensity of the contraction was found. High frequency of atypical contraction patterns, suggesting some degree of uterine incoordination was found during the active phase of labour in 10 patients, 8 of whom were primiparae. This incoordination could not be related to the effect of induction with either drug. Incoordinated contractions were associated with longer duration of labour and a tendency to more pronounced acidosis in the infant at birth, although mean values still fell in the normal range. Ominous FHR patterns were only seen in 2 cases of uterine hyperactivity during induction of labour.

Acidosis↗

PubMed1989

Patterns of uterine contractions and prolonged uterine activity using three methods of breast stimulation for contraction stress tests.

The contraction patterns in 378 breast-stimulated contraction stress tests administered to 213 women are described. The subjects were assigned sequentially to one of four intervention groups: bilateral manual breast massage, unilateral pump stimulation, heating pad stimulation, and placebo. There was a marked increase in the proportion of tests with three to four contractions in 5-minute intervals after the interventions occurred. Twenty-five percent of all tests showed prolonged uterine activity, occurring most frequently in women with postdate gestations using manual massage or breast pump stimulation. The duration of prolonged contractions ranged from 1.5-8 minutes, with 19% lasting from 4.5-8 minutes. There was no difference in the incidence of fetal heart rate abnormalities between tests with and without prolonged uterine activity, and no late decelerations occurred in tests with tachysystole.

Adolescent↗

PubMed1985

[Influence of arachidonic acid metabolic inhibitors upon uterine contractions].

The stimulating action of uterine contractions of cyclooxygenase products and 5-lipoxygenase products in an arachidonic acid cascade and the role of the inhibitors of both pathways have recently been the subject of much attention. We studied the influences of these drugs using the myometriums of pregnant rats. The inhibitory effects on pregnant uterine contractions (in vitro) were in the order beta 2-stimulants (procaterol, pirbuterol) greater than AA-861 greater than flurbiprofen greater than indomethacin greater than BW-755C. The inhibitory potency was reinforced by concurrent administration of AA-861 and flurbiprofen. Stimulation of the uterine contractions by Leukotriene (LT) was LTD4 greater than LTC4, and also the inhibition of the LT strain was AA-861 greater than flurbiprofen. The stimulation of PGE1 analog (ONO-802) revealed the reaction of LT + AA-861 (-) and LT + flurbiprofen (+/-). As to the changes in c-AMP and c-GMP in the bath medium before and after the administration of each drug, the change in the administration of the LT strain was slight, and an increase in c-AMP and a decrease of c-GMP were noted following the administration of contraction inhibitory substances. Its variation ratios were noted, in the order: increase in c-AMP of AA-861 + flurbiprofen greater than pirbuterol AA-861 greater than BW-755C, and decrease in c-GMP of pirbuterol greater than AA-861 + flurbiprofen greater than A-861 greater than BW-755C.

Adrenergic beta-Agonists↗

PubMedDate not supplied

Effects of physical activity and life-style factors on uterine contraction frequency.

In this cohort study, uterine contractions were recorded in 81 low-risk pregnant women who wore ambulatory tocodynamometers continuously during three 72-hour periods at advancing gestational ages. During these periods, they also recorded their daily activities in a diary. Examination of the data, in general, revealed no association between uterine contraction frequency and habits such as smoking, alcohol consumption, or drinking caffeinated beverages. Physical activities, such as prolonged standing, heavy housework, lifting, or organized exercise also did not appear to affect uterine contraction rates. Only climbing stairs and walking were associated with increased contraction frequencies, but this effect, although statistically significant, was relatively small in magnitude and was present only during the last gestational age period monitored (30 to 33 weeks).

Cohort Studies↗

PubMed1979

[Inhibition of premature uterine contractions].

Various drugs used to stop premature uterine contractions are discussed in the paper. Particular attention is paid to beta-mimetic drugs. The results of ming Partusisten, one of beta-mimetic drugs, is presented on the material of 104 patients with threatening immature and premature labour. Partusisten was administered in the form of intravenous drip infusion or tablets. During treatment monitoring of the uterine contractility and of foetal heart rate took place. Inhibition of the uterine contraction activity was successful in 100 per cent of cases. In 60,9 per cent in the group of threatening immature labour and in 38,1 per cent in the group threatening premature labour, the delay of delivery was more then 28 days. The delay of delivery by 48 hours was 87 per cent and 84 per cent in both groups respectively. Tachycardia was one of the first side effects observed in 15,2 per cent of cases. There is also presented an example of pregnancy when delivery was delayed by 21 days in spite of premature outflow of amniotic fluid (at a high rupture of membrane). The authors are of the opinion that Partusisten is very effective and gives little side effects, preventing premature uterine contractions. Dosage should be individualized according to the case and labour advancement, and should be based on topographic evaluation of uterine contraction. Negative influence of the drug on foetuses was not observed.

Abortion, Spontaneous↗

PubMed1986

Uterine contraction pressures with oxytocin induction/augmentation.

Uterine contraction pressures were quantified (in Montetevideo units) in 109 women at term gestation who received oxytocin for induction or augmentation of labor and whose labor resulted in a spontaneous vaginal delivery. Newborn five-minute Apgar scores were greater than or equal to 8 in 108 of the 109 neonates, and no immediate neonatal morbidity was attributable to the oxytocin stimulation of labor. Women undergoing oxytocin induction had significantly greater uterine contraction pressures than those with oxytocin augmentation. During oxytocin induction 91% of women achieved at least 200 to 224 Montevideo Units and 40% at least 300 Montevideo units versus 77 and 7.7%, respectively, during augmentation of labor. With concurrent fetal monitoring these levels of uterine activity should be sought before consideration of a cesarean delivery because of presumed cephalopelvic disproportion or failure to progress.

Drug Administration Schedule↗

PubMed1989

Controlled trial of hydration and bed rest versus bed rest alone in the evaluation of preterm uterine contractions.

Patients who are seen with uterine contractions but without documented change in cervical dilation or effacement are often treated with intravenous hydration before the initiation of intravenous tocolytic therapy. This is done with the intention of stopping uterine activity in patients with false preterm labor. A prospective randomized study was conducted to evaluate the effect of hydration on preterm uterine contractions in patients without proved preterm labor. A total of 28 patients were treated with bed rest and an intravenous bolus and subsequent continuous infusion of 5% dextrose in lactated Ringer's solution. A control group of 20 patients were treated with bed rest alone. Uterine activity and arrest of uterine contractions were compared between the two groups. Contractions stopped in 54% of the patients treated with hydration, whereas contractions stopped in 40% of the patients in the control group. This difference was not statistically significant. As a crossover study, those in the control group with contractions that continued after the initial observation period were subsequently treated with intravenous fluids. Only one patient in this group stopped contracting. Of all patients whose contractions with either therapy, 18% eventually were delivered of preterm infants. This included 20% of the hydration group and 14% of the control group. The use of hydration as a pretherapy indicator to differentiate true preterm labor from false preterm labor could not be supported by this study. In addition, patients whose contractions stopped with either hydration or bed rest are at increased risk of subsequent preterm delivery.

Bed Rest↗

PubMed1977

Evaluation of an impedance measurement technique for uterine contraction recording.

An electronic system for the detection of uterine contractions by impedance measurement was evaluated in 30 subjects during the first stage of labor. The advantage of the system was patient comfort and ease of application of the recording electrodes. Simultaneous recordings of uterine contraction activity with conventional extra- or intra-uterine recording systems were made. The available evidence from this study indicated that 82 to 84% of the uterine contractions were accurately detected and that the onset and end of each uterine contraction is a reliable parameter of impedance measurement.

Adolescent↗

PubMed1990

The effect of disopyramide on uterine contractions during pregnancy.

To evaluate the effect of disopyramide on uterine contractions during pregnancy, the drug was given for 48 hours to 10 women with indications for labor induction. Placebo was given to 10 other women with the same indications for induction. During the study period, regular uterine contractions occurred in 10 women in the study group, as compared with none in the control group (p less than 0.0001). Eight women in the study group were delivered of infants within 48 hours, as compared with none in the control group (p less than 0.0001). The mean time until the appearance of regular uterine contractions in the study group (4.15 +/- 1.76 hours) was significantly shorter (p less than 0.001) than that in the control group (56.13 +/- 5.28 hours). Patients who were not delivered of infants within 48 hours received other medications (prostaglandin E2, oxytocin). The mean maternal blood level of disopyramide at the time of appearance of uterine contractions was 1.52 +/- 0.9 mg/ml. The mean maternal level at delivery was 0.93 +/- 0.43 mg/ml and the cord blood level at the time of delivery was 0.33 mg/ml (cord blood/maternal level ratio = 0.36, r = 0.73, p less than 0.05). These results indicate that disopyramide should not be used in pregnancy for antiarrhythmic purposes because it may induce uterine contractions and delivery.

Adult↗

PubMed1991

Inhibition of oxytocin-induced uterine contractions by an oxytocin antagonist in the pregnant baboon.

Uterine contractions were induced with oxytocin in anesthetized pregnant baboons (Papio anubis) at three stages of pregnancy (days 140, 156, and 169; normal gestation length, 184 days). After the contractile activity was greater than two to three contractions every 10 minutes, beta-mercapto-beta, beta-cyclopentamethylenepropionic acid1-[D-Trp2,Phe3,Ile4,Arg8]-oxytocin, a novel oxytocin antagonist produced in our laboratories, was given simultaneously with the oxytocin for 90 minutes. Contractile force (frequency x mean amplitude) was determined for 30 minutes before and for three 30-minute intervals after the oxytocin antagonist was administered. Animals at 140 days' gestation showed a significant (p less than 0.05) decrease in contractile force in the first 30-minute interval after oxytocin antagonist infusion was initiated, whereas those at days 156 and 169 showed decreases (p less than 0.05) at the second 30-minute interval. In addition, in late gestation a higher dose of oxytocin antagonist per unit of oxytocin was required to prevent uterine contractions. In conclusion, these results suggest (1) that an oxytocin antagonist can inhibit oxytocin-induced uterine contractions in the pregnant baboon and (2) that the interval from oxytocin antagonist administration to significant inhibition of uterine contractions appears to increase with advancing gestational age.

Animals↗

PubMed1990

Changes in the response to adrenergic drugs on mouse uterine contractions during pregnancy.

The effect of isoproterenol (ISO), norepinephrine (NE) and phenylephrine (PHE) on electrically-induced contractions of mice uterine horns was studied during pregnancy. At the different times of gestation adrenergic agonists always inhibited uterine contractions in the following rank order of potency: ISO greater than NE greater than PHE. Cumulative dose-response curves constructed for the effect of these amines during diestrous, and at days 3-7, 10-15, 17-21 of gestation, showed that EC50 values increased gradually as term approached, which could imply a lower capacity of the uterus to respond to adrenergic drugs. Some likely explanations for this phenomenon are proposed. It is suggested that this lower response to catecholamines at the end of pregnancy could be a cause for the reduced success of beta 2-adrenergic drugs to stop premature labor.

Adrenergic Agonists↗

PubMed1990

Rat uterine contraction by kallikrein and its dependence on uterine kininogen.

Smooth muscle responses to kallikrein (EC 3.4.21.8) are generally considered to result from kinin formation. In the present study, this premise was reexamined with respect to the isolated rat uterus. Rat submandibular gland kallikrein produced contractions of the rat uterus but the contractions disappeared after successive additions of the same dose of the enzyme to the preparation. Kallikrein-induced rat uterine contractions as well as bradykinin-induced contractions were enhanced by rat submandibular gland bradykinin potentiating factor. The incubation of kallikrein with rat uterine extract in the presence of a kininogen-depleted rat uterus produced kinin which elicited the uterine contraction. An extract from uterine horns previously depleted of kininogen was prepared. Incubation of this extract with kallikrein in a bath containing a kininogen-depleted rat uterus did not evoke uterine contraction. The incubation of four rat uterine horns with kallikrein in the presence of a uterine horn previously depleted of kininogen elicited contractions of the depleted uterus. These results suggest that the contraction produced by kallikrein involves kinin release from the uterus.

Animals↗

PubMed1987

[Basic studies of the effects of various kinds of tocolytics on uterine contraction in pregnant rats].

The effects of various substances involved in the inhibition of uterine contraction on the uterine muscle of pregnant rats were studied in vitro in terms of uterine contraction and alterations in cyclic nucleotides. 1) The inhibitory effect of 4-aminoantipyrine (4AA) on uterine contraction showed a pattern of decline, being less potent that tranylcypromine. The effect of nifedipine was the most potent, followed by ritodrine, tranylcypromine, RU 486 and 4AA, in that order. The inhibitory effects were diminished by administration of ONO-802.PGF2 alpha. 2) Cyclic nucleotide levels changed according to the potency of each agent in the process of inhibition. Although the level of c-AMP tended to increase and that of c-GMP tended to decrease, there were no changes in their levels when nifedipine was administered. 3) Blood and uterine muscle levels of c-AMP were increased in pregnant rats that had been given ritodrine prior to hysterectomy, and there was no inhibitory effect of ritodrine in comparison with pregnant rats that had not been given the agent. The pregnant rats that had been given ritodrine prior to hysterectomy also showed no significant change in the level of c-AMP in the bath-medium.

Abortifacient Agents↗

PubMed1991

Parathyroid hormone-related protein inhibits stimulated uterine contraction in vitro.

The effect of parathyroid hormone-related protein (PTHrP) fragments 1-34, 38-64, and 67-86 on acetylcholine-stimulated rat uterine contraction was examined in vitro. In addition, the possibility that PTHrP-(38-64) or (67-86) influenced relaxation caused by PTHrP-(1-34) was also investigated. Contraction of uterine horns was stimulated with 10(-6) or 10(-5) M acetylcholine. PTHrP-(1-34) reduced the magnitude of acetylcholine-stimulated uterine contraction. This effect was dose related over a concentration range of 10(-9)-10(-6) M. Neither PTHrP-(38-64) or PTHrP-(67-86) at concentrations of 10(-8)-10(-6) M affected uterine contraction stimulated by 10(-6) M acetylcholine. These fragments did not affect the relaxation caused by 10(-7) M PTHrP-(1-34). These results demonstrate that (1) PTHrP-(1-34) at 10(-6) M influences contraction of the rat myometrium and (2) the muscle relaxant activity of PTHrP is associated with the first 34 N-terminal amino acids.

Acetylcholine↗

PubMed1989

Blockade of epidermal growth factor-induced uterine contractions by indomethacin or nordihydroguaritic acid.

Epidermal growth factor (EGF) induces uterine contractions in an in vitro system. As an initial approach to elucidating the cellular mechanism for this action of EGF, we have characterized this effect pharmacologically in uteri from castrate, estrogenprimed mature rats. EGF-induced contractions are observed in both intact tissue and isolated myometrium, are dependent on extracellular calcium and are inhibited by nifedipine and chlorpromazine. Both indomethacin and nordihydroguaritic acid (NGA) inhibit EGF-induced uterine contractions. At the maximum doses which do not affect contractile responses to prostaglandin E2 or carbachol, indomethacin (10 microM) alone or NGA (1 microM) alone only decrease the effect of EGF by 60 to 80%, but indomethacin and NGA in combination abolish totally the response to the growth factor. Arachidonic acid also causes uterine contractions in this system. EGF increases uterine contractions in the presence of a submaximal (1 microM) but not a maximal (10 microM) dose of arachidonic acid. These findings suggest that EGF-induced contractions result from a mobilization of myometrial arachidonic acid, production of intermediates via both lipoxygenase and cyclooxygenase catalyzed pathways and a resultant influx of extracellular calcium.

Animals↗

PubMed1992

Fetal viability and fetal growth after prolonged uterine contractions induced by progesterone withdrawal in late pregnancy in rats.

The hypothesis that sustained uterine contractile activity is the direct cause of fetal death after progesterone withdrawal in late pregnancy in rats was investigated. Pregnant rats were subjected to progesterone withdrawal on day 15 of pregnancy by injecting 2 mg mifepristone (RU 486) kg-1 or by ovariectomy with oestradiol replacement (200 ng day-1). Uterine contractile activity (force and frequency) at 4 h, but not at 2 h, in rats injected with mifepristone was significantly higher than in rats injected with vehicle. The contractile activity in mifepristone-treated rats remained higher than in control rats, at 12, 24 and 48 h. Fetal viability 36 h after mifepristone injection, when uterine contractions had lasted for 32 h, was not significantly different from fetal viability in rats injected with vehicle, but at 42 h after mifepristone injection, fetal viability was significantly reduced. In ovariectomized rats, uterine contractile activity at 12, 24, 36 and 48 h, but not at 8 h, was significantly greater than in ovariectomized rats with progesterone replacement (4 mg day-1). Fetal viability at 42 h after the operation, when uterine contractions had lasted for 30 h, was not significantly reduced, but it was significantly reduced at 48 h. When ovariectomized rats had been left to develop uterine contractions for a period before progesterone was injected, deprivation of progesterone and prolonged uterine contractions for about 30 h did not reduce fetal viability or fetal growth determined on day 18, but it did so 3 days later, on day 21. Administration of 5 mg isoxuprine kg-1 twice a day, which suppressed uterine contractions, improved fetal viability in ovariectomized rats at the earlier stage, but not at the later stage. Nevertheless, isoxuprine did improve fetal growth at the later stage in these ovariectomized rats. It is concluded that increased uterine contractile activity sustained for 32 h or less does not reduce fetal viability, but longer periods of contraction may be the cause of fetal death.

Animals↗

PubMed1988

Association between fetal movements and uterine contractions in the active phase of labor.

Fetal body movements were studied for 40 minutes during the active phase of labor in 15 parturients. The total duration of fetal movements constituted 8.2% of the recording period, with a frequency of 3.8 +/- 2.1 per ten minutes. Of all the movements, 57.3% were associated with uterine contractions, while 40.7% of all uterine contractions were associated with fetal movements. All the fetuses moved in the first 30 minutes of the study period. The fetal movements that were associated with uterine contractions were longer than those not associated with contractions. Similarly, uterine contractions associated with fetal movements were longer than other uterine contractions.

Female↗