Experience with prostaglandin F2α (free acid) for the induction of labour

Labour was induced or augmented in 115 patients by amniotomy followed by intravenously administered prostaglandin F_2α (PGF_2α). The results were compared to those obtained retrospectively from a similar number of patients, matched for age, parity, induced and augmented labour, epidural anaesthesia and induction score; in whom labour had been induced by amniotomy followed by intravenous oxytocin titration. Both regimes were very effective, but there was a higher incidence of side effects in the patients receiving oxytocin. There was one maternal death associated with Prostaglandin infusion. Labour was also induced in a further group of 50 patients by amniotomy followed by oral PGF_2α (free acid). 42 patients (84%) were successfully induced. Vomiting and diarrhoea occurred in 22 patients (45%).     

Preinduction cervical priming in high risk pregnancy — experience with a new sustained release PGE2 vaginal film

Experience with a new sustained release PGE2 formulation is presented. 111 high risk primiparae with very poor cervical scores (<3) were studied. In 59 patients, labour was induced by forewater amniotomy and I.V. oxytocin. In the remaining 52 patients, film containing 850 ug of PGE₂ was inserted into the vagina to ripen the cervix 24 hours prior to induction of labour. Indications for elective delivery and maternal characteristics were similar in both groups. There were significant changes in the cervical state within 12 hours of vaginal insertion. By 24 hours, 19 patients receiving vaginal film (36.5%) had established labour of whom 13 proceeded to vaginal delivery. Significantly fewer patients in the priming group required Caesarean delivery. No untoward maternal or fetal side effects were observed.Safety, ease of administration and efficacy make this new PGE₂ formulation a useful agent for priming of the very poor primiparous cervix prior to induction of high risk labour.     

Selective induction of labour following administration of an oral prostaglandin E2 0.5 mg tablet hourly

Induction of labour was performed on 20 patients with favourable induction features by amniotomy and administration of a fixed dose of 0.5 mg of prostaglandin E₂ (PGE₂) hourly. Effective uterine action resulted in a mean time to delivery of 6 hrs 57 mins in primagravid patients and 4 hrs 40 mins in multigravid subjects. In two patients an intravenous oxytocin infusion was used to assist labour. There were no significant maternal or fetal side effects.     

Neonatal Jaundice and Maternal Oxytocin Infusion

A prospective study of 78 neonates provides evidence for an association between maternal oxytocin infusion and neonatal jaundice. On the second and fifth days infants of mothers whose labour had been induced by amniotomy followed immediately by intravenous oxytocin (group C) had mean total bilirubin levels significantly higher (P <0·05) than did infants whose mothers had had a spontaneous onset of labour and did not require oxytocin (group A). Bilirubin levels in infants of mothers whose onset of labour was spontaneous but required oxytocin to accelerate progress (group B) did not differ significantly from group A.Though these findings suggest a dose dependent effect of oxytocin, other possible explanations are suggested which take into account other drugs administered to the mother and also differences in the corticosteroid status of the groups of infants.     

The PGE2 vaginal film: An alternative to conventional induction in multiparae with poor cervical scores

In a study involving 50 multiparous subjects with poor cervical scores (⪕3), induction of labour by conventional amniotomy and oxytocin was compared with preinduction cervical ripening using a single administration of prostaglandin E₂ (850ug) in a new vaginal film formulation. Indications for elective delivery, maternal characteristics and distribution of cervical scores in the two groups were similar. Significant changes in mean cervical score were achieved within 12 hours of film insertion. In this group, 11 subjects (45.8%) established labour within 12 hours and a further 8(33.3%) did so before 24 hours so that only 5 cases required amniotomy and oxytocin. Instrumental delivery was less in this group and none of these subjects required Caesarean section for a failure of induction. No adverse maternal or fetal side effects were observed. Convenience, ease of administration and stability of this new prostaglandin formulation make it a useful alternative to conventional induction of labour in the multiparous patient with a poor cervical score.     

COOK双球囊导管在足月妊娠引产中的临床研究

目的:探讨宫颈双球囊导管在足月妊娠促宫颈成熟及引产中的有效性和安全性。方法:回顾性选择符合有引产指征、单胎头位、宫颈评分6分的100例足月妊娠孕妇进行分析,其中51例采用COOK双球囊导管引产者为COOK组,49例采用小剂量缩宫素引产者为对照组,比较分析两组宫颈成熟度、引产效果、分娩方式、分娩结局、产后出血、新生儿窒息等情况。结果:100例孕妇引产指征主要是延期(过期)妊娠、羊水过少、妊娠期高血压、妊娠期糖尿病、妊娠合并甲减等。COOK组51例促宫颈成熟有效49例(96.08%),对照组有效16例(32.65%),COOK组促宫颈成熟有效率显著高于对照组,差异有统计学意义(P0.05)。COOK组诱发临产时间明显少于对照组,两组差异有统计学意义(P0.05)。COOK组阴道分娩41例(80.39%),剖宫产10例(19.61%);对照组阴道分娩20例(40.82%),剖宫产29例(59.18%),COOK组阴道分娩率明显高于对照组,剖宫产率明显低于对照组,两组差异均有统计学意义(P0.05)。两组之间的总产程、羊水污染率、新生儿窒息率、产后出血率等围产结局无显著差异(P0.05);COOK组引产过程中出现不良反应6例(11.76%),对照组5例(10.20%),两组无显著差异(P0.05)。结论:COOK双球囊导管促宫颈成熟及引产效果明显优于缩宫素,且不增加不良反应的发生,由于操作简单,有效性和安全性高,值得国内临床推广。     

Absence of Antidiuresis during Administration of Prostaglandin F2α

Water diuresis was induced in six patients in mid-pregnancy. Three were then given oxytocin and the remainder prostaglandin F₂α (PGF₂α), both drugs being infused intravenously in doses used to induce labour at term. Pronounced antidiuresis occurred with oxytocin, whereas PGF₂α showed no such effect. The probable absence of any risk of water intoxication when using PGF₂α in inducing labour may be of particular value when maternal pre-eclampsia or renal disease is present.     

Delivery after caesarean section: review of 2176 consecutive cases.

A total of 2176 consecutive patients who had had one previous caesarean section were studied retrospectively. A repeat elective caesarean section was performed in 395 (18.2%). Labour started spontaneously in 1363 patients, 301 of whom were given oxytocin to accelerate inert labour, and was induced by amniotomy and infusion of oxytocin in 418 women; 1618 of these 1781 patients (90.8%) delivered vaginally. Patients who had had a previous vaginal delivery were more likely to deliver vaginally again. Those women in whom the initial caesarean section had been performed during labour before the cervix was 4 cm dilated were less likely to deliver vaginally than those who had progressed further in labour or those who had had an elective caesarean section. Similarly, those who received oxytocin to stimulate inert labour were more likely to require a repeat caesarean section than those who did not. The uterine scar ruptured in only eight (0.45%) of the 1781 patients allowed into labour. The risk of rupture of the scar was not increased by the use of oxytocin alone either to induce or to accelerate labour. The combination of oxytocin to accelerate labour and epidural analgesia to provide pain relief, however, was associated with an increased incidence of scar rupture. Labour may be safely allowed in women who have had a previous caesarean section, most of whom will deliver vaginally. Induction of labour does not increase the risk of either a repeat caesarean section or rupture of a uterine scar.     

The induction of labour by the intravenous infusion of prostaglandin F2α

labour was induced by the intravenous infusion of prostaglandin F_2α in 106 patients at 36–44 weeks of pregnancy. The induction was successful in 80% of the women. The total dose needed ranged from 0.1 to 14.2 mg of PGF_2α. The uterine activity and fetal heart rate were recorded by cardiotocography. The contraction pattern and induction-delivery time were the same as reported for induction with oxytocin. In one case uterine hyperactivity occurred after rupture of the membranes. No serious adverse effects were seen, but in a few cases local irritation was noted at the site of infusion. The condition of the infants was generally good.It might be concluded that PGF_2α seems valuable for the induction of labour, but due to the risk for overstimulation careful supervision is needed.     

Loss of myometrial oxytocin receptors during oxytocin-induced and oxytocin-augmented labour

Oxytocin is used widely for the induction and augmentation of labour, but there is little information about the dynamics of oxytocin receptors in human myometrium during parturition, and the possible effect of oxytocin infusion. This information is important because G protein-coupled receptors, such as the oxytocin receptor, undergo desensitization after prolonged or repeated stimulation. The concentration of myometrial oxytocin receptors and the steady state of its mRNA were measured in patients undergoing Caesarean sections before or during spontaneous or induced labour. The concentration of receptors before labour was 477 (175-641) fmol mg(-1) protein (median, quartile range), and decreased to 140 (72-206; P < 0.05) and 118 (69-75; P < 0.01) fmol mg(-1) protein during prolonged oxytocin-augmented and oxytocin-induced labour, respectively. The corresponding oxytocin receptor mRNA concentrations decreased by 60- and 300-fold, respectively. The decrease in receptor binding and mRNA in women receiving oxytocin infusion indicates that homologous receptor desensitization occurs in vivo.     

Induction of human labor at term: uterine activity, inducibility, duration and neonatal jaundice

A total of 821 patients, 39-40 weeks pregnant, was obstetrically normal at admission. In 212 of them intra-uterine pressure (IUP) was monitored before and during inducing labor by oxytocin, in 212 patients delivery was also induced by oxytocin but not monitored, in 197 by combining oxytocin and amniotomy, and 200 had spontaneous delivery. Inducibility could be predicted by uterine baseline activity and a 50 mu i.v. shot of oxytocin, together with determination of cervical status and placental location. The duration of labour induction was affected by parity, placental location and cervical status, but was predicted only to a minor degree by baseline activity and uterine oxytocin sensitivity. Amniotomy did not affect caesarean, section rate. The newborn child benefited from IUP monitoring: fewer transfers to pediatrics were necessary, there was less neonatal jaundice and fewer blood exchanges. It is assumed that if labor is not monitored through IUP, oxytocin may cause neonatal hyperbilirubinaemia through episodes of increased uterine resting pressure.     

Clinical evaluation of endocervical prostaglandin E2-triacetin-gel for preinduction cervical softening in pregnant women at term

In an open randomized clinical trial 100 pregnant women with low Bishop Scores at term were treated either with intracervical Prostaglandin (PG) E₂ (0.5 mg in 2.5 ml triacetin-gel) 12 hours before labor induction with intravenous oxytocin or with oxytocin infusion alone. In 46 of the 50 pretreated patients (92 %) the Bishop Score progressed at least 3 points, in four cases only 2 points. The mean Bishop score in the untreated patients increased insignificantly. After PGE₂-gel administration 16 patients delivered during the 12 hour interval compared to 3 in the group without pretreatment. The first induction attempt was successful in 14 (64 %) of the 22 patients that were left to be induced after cervical softening and in 26 (57 %) of the 47 women without cervical priming. The Cesarean section rate was 10% (n=5) in the PGE₂-gel group and 12% (_n=6) in the control group. Dosage of oxytocin required for labor induction was significantly lower after cervical softening. No serious fetal or maternal side effects were observed after PGE₂ pretreatment.     

Review: significance of the inhibition by prostaglandins and cyclic GMP of oxytocinase activity in human pregnancy and labour

The uterotonic action of oxytocin has been known for many decades. This neurohypophysial hormone is thought to play a functional role in human parturition. Since 1968, prostaglandins have also been implicated in parturition. These two groups of uterotonic agents have now a recognized therapeutic role, and are widely used in the induction of labour and in fertility control. However, the mechanism of action and the interrelationship between these endogenous compounds in pregnancy are poorly understood. In this article, the role and interaction of oxytocin, oxytocinase and prostaglandins in human pregnancy and labour have been reviewed. Inhibition of oxytocinase activity by prostaglandins has been suggested as a mechanism in parturition. Possible involvement of cyclic GMP in the initiation of labour has also been discussed.     

Renal prostaglandins for induction of labour — A dual clinical advantage in toxemia of pregnancy

Prostaglandin A₁ is known to be an antihypertensive vasodepressor agent produced by the kidney and has the basic potentialities of a hormone. No information is available at present concerning its effect on the human pregnant uterus and whether it can be used as an oxytocic compound to induce labour. The uterine stimulating and labour inducing ability of PGA₁ was evaluated in 10 cases ; seven patients were suffering from pregnancy toxemia while three were normal pregnancies near full term. Cardiotocographic tracings showed that uterine activity was markedly stimulated to a degree sufficient to induce labour. Continuous i.v. infusions at a rate of 0.25–1.0 μg/Kgm/min given over a fixed period of only 6 hours resulted in delivery in all cases except one following the discontinuation of administration. Beneficial effects on blood pressure were observed in toxemic subjects. Potentially serious FHR patterns and occasional hypertonus during therapy were seen and stress the need for more information to evaluate the safety, optimum dosage and duration of infusion as well as the place of this approach in clinical practice for the management of pregnancy toxemia. The absence of antidiuretic effect, the hypotensive response and uterine stimulating property of PGA₁ indicate a possible advantage in toxemia of pregnancy as compared to oxytocin infusions.     

Inducing labour with vaginally administered prostaglandin E2.

In 50 consecutive pregnant women at a 125-bed community hospital with 1000 deliveries annually, labour was induced with prostaglandin E2 administered intravaginally. There were no stillbirths or neonatal deaths, and complications in the mothers were few. In nine women (18%) oxytocin was subsequently administered because of a failure of labour to progress; in spite of this, cesarean section was required in two (4%) of the patients. The overall cesarean section rate was 6%. Prostaglandins have been used routinely to induce labour in the United Kingdom for several years. This noninvasive method is safe, effective and well received by women in a community hospital setting, including those wanting "natural childbirth".     

Influence of simultaneous low amniotomy and oxytocin infusion and other maternal factors on neonatal jaundice: a prospective study.

In a prospective study of 196 consecutive single births a significant increase in serum bilirubin concentrations was found in infants born after low amniotomy induction and oxytocin infusion compared with those born spontaneously. This relationship was not dose-dependent and may have been associated with artificial interruption of pregnancy rather than the oxytocin itself. Infants delivered after spontaneous labour accelerated by oxytocin showed no such increase. The hormonal surge at the spontaneous onset of labour may affect fetal enzyme induction, but other factors, such as methods of infant feeding and oral contraceptive use, were found not to be significant.     

Effects of oxytocin outside pregnancy

For a long time, oxytocin was regarded as a pregnancy hormone released by the hypophysis to stimulate labour and milk ejection. In the present survey, data have been collected from the literature to show the spectrum of the hitherto known functions of oxytocin outside pregnancy. It is now known that oxytocin receptors can occur almost ubiquitously in the organism, that oxytocin is also formed outside of the brain and that oxytocin has functions in a number of organs. In the first part of the survey, stimuli that contribute to an increase in oxytocin release are compiled. In the second part, details are given on the individual oxytocin targets. Although the majority of findings are based on the results of animal experiments, there are already a number of studies that indicate similar effects of oxytocin in humans. According to the current state of knowledge, oxytocin appears to be involved in functions in the following organs: male and non-pregnant female reproductive tract, pancreas, cardiovascular system, kidney, brain and breast. There are indications that oxytocin may also have actions in other organs. There continues to be a considerable need for research into oxytocin in order to better understand the physiological and pathophysiological actions and to be able to derive possible therapeutic uses. Further light on the spectrum of functions of oxytocin may be cast by the possibility of the use of oxytocin antagonists.     

Effects of labour and medication on major lymphocyte subsets in cord

It is envisaged that flow cytometric analysis of lymphocyte subsets in cord blood may be used as a biomarker for effects on the immune system of exposure to environmental factors. In order to investigate the possible application of this parameter, we first studied the effects of other factors that may influence the outcome of subset analysis in cord blood. FACS analysis was performed in 112 pairs of umbilical cord blood and of peripheral maternal blood sampled at labour. Whereas in maternal blood no statistically significant effects of medication during labour on T lymphocyte numbers and NK cells were found, in oxytocin and in oxytocin and prostaglandin treated mothers B cell numbers showed a statistically significant increase. In cord blood, the course of labour and or medication during labour were identified as the most important factors determining distribution of major lymphocyte subsets. In cord blood after deliveries without medication or after neuroplegic analgesia NPA, the mean percentage of cord blood T lymphocytes CD3 was highest 59 and that of NK lymphocytes CD3- CD16 56 lowest 20 . The mean percentage of T lymphocytes was significantly lower 52 and that of NK lymphocytes higher 28 in cord blood where deliveries were done under NPA in combination with infusion of oxytocin. The combination of NPA with oxytocin and induction of labour by prostaglandin E2 led to a further reduction of T lymphocytes and an increase of NK cells 39 and 38 respectively. The changes in ratio of T and NK lymphocytes were due both to decreasing absolute counts of T lymphocytes and increasing counts of NK lymphocytes. Thus, the effects of labour and or medication during labour must be taken into account when this parameter is applied as a potential biomarker of effects of environmental factors on the immune system.     

Local and systemic control of myometrial contractile activity during labour in the sheep

The relative contribution of systemic versus local (intrauterine) factors in the activation and stimulation of the sheep myometrium during labour was examined using an in-vivo myometrial explant preparation. Myometrial tissue alone (MYO) or with attached endometrium (ENDO/MYO) was removed from the pregnant uterine horn, sutured to a stainless-steel frame and placed into the omental fat. After 7-10 days the explants developed a pattern of electromyographic activity qualitatively similar to that of the uterine myometrium. Induction of preterm labour by infusion of ACTH (66.6 ng/min for 15 min every 2 h) to the fetus resulted in a reduction in plasma progesterone concentrations and increases in values of oestradiol-17 beta and 13,14-dihydro 15-keto PGF-2 alpha in maternal plasma. The onset of labour, which followed these endocrine changes, was characterized by an increase in EMG burst frequency and reduction in burst duration occurring simultaneously in both the uterine myometrium and in the explants. The response of the uterine and explant myometrium to oxytocin also exhibited a parallel significant increase over the 24-h period leading to delivery. No differences were apparent between the explants containing myometrial tissue alone or those comprising endometrial and myometrial tissue. There was no significant change in uterine or explant EMG activity, or oxytocin responsiveness, after saline administration to the fetus. The pattern of EMG activity changes during spontaneous labour were not distinguishable from those during ACTH-induced labour. As with oxytocin, the responsiveness of the explants to electrical stimulation increased significantly at labour compared to pre-labour. These data suggest that factors within the systemic circulation play a major role in both the onset of labour contractions and the increased response to electrical or hormonal (oxytocin) stimulation during parturition in sheep.     

Effects of labour and medication on major lymphocyte subsets in cord

It is envisaged that flow cytometric analysis of lymphocyte subsets in cord blood may be used as a biomarker for effects on the immune system of exposure to environmental factors. In order to investigate the possible application of this parameter, we first studied the effects of other factors that may influence the outcome of subset analysis in cord blood. FACS analysis was performed in 112 pairs of umbilical cord blood and of peripheral maternal blood sampled at labour. Whereas in maternal blood no statistically significant effects of medication during labour on T lymphocyte numbers and NK cells were found, in oxytocin and in oxytocin and prostaglandin treated mothers B cell numbers showed a statistically significant increase. In cord blood, the course of labour and or medication during labour were identified as the most important factors determining distribution of major lymphocyte subsets. In cord blood after deliveries without medication or after neuroplegic analgesia NPA , the mean percentage of cord blood T lymphocytes CD3 was highest 59 and that of NK lymphocytes CD3- CD16 56 lowest 20 . The mean percentage of T lymphocytes was significantly lower 52 and that of NK lymphocytes higher 28 in cord blood where deliveries were done under NPA in combination with infusion of oxytocin. The combination of NPA with oxytocin and induction of labour by prostaglandin E2 led to a further reduction of T lymphocytes and an increase of NK cells 39 and 38 respectively . The changes in ratio of T and NK lymphocytes were due both to decreasing absolute counts of T lymphocytes and increasing counts of NK lymphocytes. Thus, the effects of labour and or medication during labour must be taken into account when this parameter is applied as a potential biomarker of effects of environmental factors on the immune system.