Premature labour

Adrenergic receptor agonists are also used to treat premature labour by causing uterine relaxation. Fenoterol and ritodrine are frequently used. The effectiveness of long-term tocolysis is controversial, since both desensitization of the receptors and the symptomatic nature of this treatment may limit their effects to 1-2 days according to one large study. 

The possibility still exists that selective COX-2 inhibitors may be used to treat cancer if the beneficial effect outweighs the side effects. They may also have a therapeutic role in treating premature labour, since labour is induced partly through the uterotonic effect of PGs synthesised by COX-2. Non-selective NSABDs such as indomethacin will also delay premature labour but they are contraindicated for this condition since they also cause early closure of the ductus arteriosus through inhibition of COX-1, which synthesises PGs maintaining patency of the ductus [5]. 

From a therapeutic point of view, it is essential to confirm the presence of bacteriuria (a condition in which there are bacteria in the urine) since symptoms alone are not a reliable method of documenting infection. This applies particularly to bladder infection where the symptoms of burning micturition (dysuria) and frequency can be associated with a variety of non-bacteriuric conditions. Patients with symptomatic bacteriuria should always be treated. However, the necessity to treat asymptomatic bacteriuric patients varies with age and the presence or absence of underlying urinary tract abnormalities. In the pre-school child it is essential to treat all urinary tract infections and maintain the urine in a sterile state so that normal kidney maturation can proceed. Likewise in pregnancy there is a risk of infection ascending from the bladder to involve the kidney. This is a serious complication and may result in premature labour. Other indications for treating asymptomatic bacteriuria include the presence of underlying renal abnormalities such as stones which may be associated with repeated infections caused by Proteus spp. 

Blaustein Why is that gravid uterus in labour unless something happened prematurely and something else has gone wrong to make that uterus different from a typical gravid uterus ... 

Ritodrine relaxes the uterine muscle and is therefore indicated to prevent premature labour. Ergometrine, oxytocin and carboprost are all indicated to induce or augment labour by inducing uterine contractions and hence can be used to cause the uterus to contract after delivery. Dinoprostone is mostly used for the induction of labour. 

Isoxsuprine has a potent inhibitory effect on vascular and uterine smooth muscle and has been used in the treatment of dysmenorrhoea, threatened abortion, premature labour and peripheral vascular diseases. Adverse effects include nausea, tachycardia, flushing and dizziness. 

It is P2 selective agonist with uterine relaxant property and preferred to suppress premature labour and delay delivery of fetus. But, use of ritodrine in suppressing labour has been found to increase maternal morbidity and neonate may develop hyperglycemia. So it... 

It is indicated in habitual abortion, failure of nidation, threatened abortion, premenstrual tension, metrorrhagia and threatened premature labour. 

Salbutamol inhibits uterine contractions and may be administered by intravenous infusion as a means of preventing premature labour. 

Surprise is at the heart of the matter. If one word can express the antidote for premature satiation, that which cannot be generated by the self but must be obtained from outside, it is surprise. Surprise, not gold, or land or labour, should be the epigrammatic font of value. 

Kullander, S., and L. Svanberg. 1985. On resorption and the effects of vaginally administered terbutaline in women with premature labour. Acta Obstet Hynaecol Scand 64 613. 

Atosiban, an oxytocin receptor antagonist, is also licensed for treatment of premature labour. This drug has fewer side effects than the / -agonists and is particularly useful if the mother has cardiac disease, because intravenous 2-agonists can cause adverse cardiac actions in the mother. 

If labour begins prematurely, before 33 weeks gestation, myometrial relax-ants (tocolytic agents) can delay it for 48 hours. Beta-2-agonists, such as ritodrine hydrochloride, are given for up to 48 hours to elicit relaxation. Longer treatment is not recommended, because of risk of adverse effects on the mother. Nifedipine and the oxytocin receptor antagonist atosiban are also used to reduce premature uterine contractile activity. 

Pj-selective agonists such as prenalterol (Figure 10.5) or dobutamine are used to stimulate heart contractility and heart rate in patients that exhibit too low blood pressure. P2-Selective agents such as terbutaline find application for relaxation and dilatation of the bronchi in the treatment of asthma or chronic obstmctive lung disease, and in the suppression of premature labour. The mechanism of P-receptor-induced relaxation of smooth muscle - cAMP-mediated phosphorylation and inhibition of myosin light chain kinase - has been described before. 

The effect of the sympathomimetic drugs on the pregnant uterus is Vciriable and difficult to predict, but serious fetal distress can occur, due to reduced placental blood flow as a result both of contraction of the uterine muscle (a) and arterial constriction (a). Pj-agonists are used to relax the uterus in premature labour, but unwanted cardiovascular actions can be troublesome. Sympathomimetics were particularly likely to cause cardiac arrhythmias (p, effect) in patients who received halothane anaesthesia (now much less used). 

Salbutamol, fenoterol, rimiterol, reproterol, pir-buterol, salmeterol, ritodrine and terbutaline are P-adrenoceptor agonists that are relatively selective for p2-receptors, so that cardiac (chiefly p -receptor) effects are less prominent. Tachycardia still occurs because of atrial (sinus node) p -receptor stimulation the P2-adrenoceptors are less numerous in the ventricle and there is probably less risk of serious ventricular arrhythmias than with the use of nonselective catecholamines. The synthetic agonists are also longer-acting than isoprenaline because they are not substrates for catechol-O-methyltransferase, which methylates catecholamines in the liver. They are used principally in asthma, and to reduce uterine contractions in premature labour. 

Premature labour use of P -adrenoceptor agonists and of dexamethasone (to prevent respiratory distress syndrome in the prematurely newborn) causes hyperglycaemia and increased insulin (and potassium) need. 

Pj-adrenoceptor agonists relax the uterus and are given by i.v. infusion by obstetricians to inhibit premature labour, e.g. isoxsuprine, terbutaline, ritodrine, salbutamol. Their use is complicated by the expected cardiovascular effects, including tachycardia, hypotension. Less easy to explain, but more devastating on occasion to the patient, is severe left ventricular failure. Possibly the combination of fluid overload (due to the vehicle) and increased oxygen demand by the heart are factors. 

Pincus R. Salbutamol infusion for premature labour—the Australian trials experience. Aust NZ J Obstet Gynaecol 1981 21(1) 1. ... 

Gromadzinska J, Wasowicz W, Krasomski G, et al. 1998. Selenium levels, thiobarbituric acid-reactive substance concentrations and glutathione peroxidase activity in the blood of women with gestosis and imminent premature labour. Analyst 123 35-40. 

It was recognized that speeding up could only be done at the cost of extra plant and a relatively uneconomical increase in the labour force, and that the provision of premature storage must result in such a dislocation of the works programme as to seriously delay completion. TTiis dislocation had to be faced at Tunnel and Eastlays, but to reduce the... 

It is used for treating premature labour. It in indicated parenterally for the emergency treatment of... 

It decreases uterine contractions and is often employed to arrest premature labour... 

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