Uterine activity during spontaneous labour after previous lower-segment caesarean section

Uterine activity was measured in three groups of labouring women who previously had a caesarean section (CS): group A included women with a previous elective CS before labour or in the early latent phase of labour and no previous vaginal delivery; group B included women with a CS in the active phase of labour and no previous vaginal delivery; group C included women with a CS and a vaginal delivery either before or after the abdominal delivery. The active contraction area profiles in the three groups were compared with those of matched control groups of nulliparae and multiparae without a uterine scar. Group A had a uterine activity profile similar to that in control nulliparae and significantly higher than that in control multiparae. The uterine activity in group B was less than that in matched nulliparae but was similar to that in matched multiparae. Group C had significantly less uterine activity than matched nulliparae but a similar profile to that in the matched multiparae. Progress of labour into the active phase in the previous pregnancy reduces the uterine activity profile in subsequent labour. Women who had had a vaginal delivery either before or after the CS (group C) exhibited uterine activity profiles similar to multiparae, suggesting that an intact scar did not affect the uterine function.     

A comparison of low-risk pregnant women booked for delivery in two systems of care: shared-care (consultant) and integrated general practice unit. II. Labour and delivery management and neonatal outcome

Summary. A random sample of low-risk pregnant women were equally divided into four groups of 63 nulliparae and multiparae each booked for care in a integrated general practice unit (GPU) and a shared-care (consultant) system. Selection criteria included only women who were admitted because they were in spontaneous labour or thought they were. Nulliparous women booked for shared-care came into hospital at a less advanced state of cervical dilatation than those booked for the GPU andspent longer (11 compared with 8 h) in hospital before delivery; the comparable durations in multiparae were 6 and 4 h. Both the first and second stages of labour were longer in the GPU-booked women but they received less pethidine and fewer had epidural analgesia; they received less electronic fetal monitoring, augmentation and forceps delivery, and fetal distress was diagnosed less often. The 1-min Apgar score was < 6 in 17.5% of infants of nulliparae booked for the shared-care system compared with 1.6% of those booked for the GPU. The intubation rate of infants of nulliparae was 11% in the shared-care system compared with no intubations in the GPU. These comparisons demonstrate the simplicity and safety of delivery of low-risk women in the GPU as compared with deliveries of similar women in a shared-care (consultant) unit.     

Oxytocin titration to achieve preset active contraction area values does not improve the outcome of induced labour

Summary. The value of controlling oxytocin titration in induction of labour by a preset uterine activity, assessed as active contraction area, was examined in a randomized study in 60 nulliparae and 54 multiparae. Each parity group was divided into two groups according to the cervical score (5 and >5) and within those four groups the women were randomly allocated to oxytocin titration against a preset frequency of 6–7 uterine contractions every 15 min, or to a preset uterine activity equivalent to the 75th centile for spontaneous labour. The length of labour was slightly, but not significantly, longer in the frequency group. The mode of delivery, Apgar scores at 1 and 5 min and cord artery blood pH values were similar with the two modes of oxytocin titration.The mean maximum dose rate of oxytocin infusion was not significantly different except in the nulliparous group with a poor cervical score. The given mean total dose of oxytocin was similar in the different groups when controlled for parity and cervical score. The results suggest that oxytocin titration to achieve uterine activity values equivalent to the 75th centile of those observed in spontaneous labour does not confer any advantage compared with the traditional practice of titrating the oxytocin infusion to achieve a preset frequency of uterine contractions.     

Oxytocin titration to achieve preset active contraction area values does not improve the outcome of induced labour

The value of controlling oxytocin titration in induction of labour by a present uterine activity, assessed as active contraction area, was examined in a randomized study in 60 nulliparae and 54 multiparae. Each parity group was divided into two groups according to the cervical score (less than or equal to 5 and greater than 5) and within those four groups the women were randomly allocated to oxytocin titration against a present frequency of 6-7 uterine contractions every 15 min, or to a preset uterine activity equivalent to the 75th centile for spontaneous labour. The length of labour was slightly, but not significantly, longer in the frequency group. The mode of delivery, Apgar scores at 1 and 5 min and cord artery blood pH values were similar with the two modes of oxytocin titration. The mean maximum dose rate of oxytocin infusion was not significantly different except in the nulliparous group with a poor cervical score. The given mean total dose of oxytocin was similar in the different groups when controlled for parity and cervical score. The results suggest that oxytocin titration to achieve uterine activity values equivalent to the 75th centile of those observed in spontaneous labour does not confer any advantage compared with the traditional practice of titrating the oxytocin infusion to achieve a preset frequency of uterine contractions.     

Intrauterine pressures in labours induced by amniotomy and oxytocin or vaginal prostaglandin gel compared with spontaneous labour

Summary. Uterine activity during the first stage of labour was measured by an intrauterine transducer in 22 women induced with intravaginal PGE2 gel, in 37 induced by amniotomy and intravenous oxytocin, and in nine women in spontaneous labour. The nulliparous women in the PGE2 gel group had a significantly longer pre-established phase of labour and a significantly shorter established phase than nulliparae induced by amniotomy and oxytocin. The mean levels of total uterine activity (kPas) during labour and the uterine activity integrals (kPas/15 min) were significantly lower in nulliparae induced with PGE2 gel than in those induced by amniotomy and oxytocin. These findings suggest that PGE2 gel has a positive, beneficial effect on cervical compliance during the pre-established phase, resulting in less myometrial effort during established labour. These effects were less evident in parous women, probably because of an innate lower cervical resistance due to their previous labours. Uterine activity patterns during the 4 h leading to full cervical dilatation in nulliparae were similar in labours induced with PGE2 gel and spontaneous labours, whereas labours induced by amniotomy and oxytocin exhibited a significantly different pattern. Expulsion of the fetus during normal labour is a function of both uterine contractions and a decrease in the cervical resistance and the data suggest that induction by PGE2 gel more closely mimics spontaneous labour, whereas the predominant effect of oxytocin is to stimulate myometrial activity.     

Optimising daytime deliveries when inducing labour using prostaglandin vaginal inserts

Objective: To determine induction start time(s) that would maximise daytime deliveries when using prostaglandin vaginal inserts.

Methods: Women enrolled into the Phase III trial, EXPEDITE (clinical trial registration: NCT01127581), had labour induced with either a misoprostol or dinoprostone vaginal insert (MVI or DVI). A secondary analysis was conducted to determine the optimal start times for induction by identifying the 12-h period with the highest proportion of deliveries by parity and treatment.

Results: Optimal start times for achieving daytime deliveries when using MVI appear to be 19:00 in nulliparae and 23:00 in multiparae. Applying these start times, the median time of onset of active labour would be approximately 08:30 for both parities and the median time of delivery would be the following day at approximately 16:30 for nulliparae and 12:00 (midday) for multiparae. Optimal start times when using DVI appear to be 07:00 for nulliparae and 23:00 for multiparae. Using these start times, the median time of onset of active labour would be the following day at approximately 04:00 and 11:50, and the median time of delivery would be approximately 13:40 and 16:10, respectively.

Conclusions: When optimising daytime deliveries, different times to initiate induction of labour may be appropriate depending on parity and the type of retrievable prostaglandin vaginal insert used.     

Intrauterine pressures in labours induced by amniotomy and oxytocin or vaginal prostaglandin gel compared with spontaneous labour

Uterine activity during the first stage of labour was measured by an intrauterine transducer in 22 women induced with intravaginal PGE2 gel, in 37 induced by amniotomy and intravenous oxytocin, and in nine women in spontaneous labour. The nulliparous women in the PGE2 gel group had a significantly longer pre-established phase of labour and a significantly shorter established phase than nulliparae induced by amniotomy and oxytocin. The mean levels of total uterine activity (kPas) during labour and the uterine activity integrals (kPas/15 min) were significantly lower in nulliparae induced with PGE2 gel than in those induced by amniotomy and oxytocin. These findings suggest that PGE2 gel has a positive, beneficial effect on cervical compliance during the pre-established phase, resulting in less myometrial effort during established labour. These effects were less evident in parous women, probably because of an innate lower cervical resistance due to their previous labours. Uterine activity patterns during the 4 h leading to full cervical dilatation in nulliparae were similar in labours induced with PGE2 gel and spontaneous labours, whereas labours induced by amniotomy and oxytocin exhibited a significantly different pattern. Expulsion of the fetus during normal labour is a function of both uterine contractions and a decrease in the cervical resistance and the data suggest that induction by PGE2 gel more closely mimics spontaneous labour, whereas the predominant effect of oxytocin is to stimulate myometrial activity.     

Intrauterine-pressure studies in African nulliparae: delay, delivery and disproportion

Summary. Uterine activity was measured in 43 African nulliparae who were in the active phase of spontaneous labour and in whom delay in cervical dilatation had occurred. Details of labour were recorded on a partogramme, on which an alert and an action line had been drawn, and which were 2 h apart. Delay was defined as a cervical dilatation rate of <1 cm/h. Uterine activity was measured with a fluid-filled intrauterine catheter, an external strain gauge and a pressure-curve integrator. The uterine activity levels which were observed in association with delay are considerably less than those associated with normal labour progress. The uterine activity levels that were associated with pitocin augmentation after the action line and which resulted in vaginal delivery have been analysed. They were similar to the levels observed in normal labour. The uterine activity levels which were associated with 'failure to progress in labour' beyond the action line have also been analysed. It is argued that a minimum uterine activity level of 1800 kPas/15min is required to fully test the cephalopelvic relation.     

Induction of Labour With Prostaglandin Gel in Grand Multipara with a Previous Caesarean Delivery

ObjectiveThis study sought to evaluate the safety of induction of labour with prostaglandin E₂ (PGE₂) gel in grand multiparous (GMP) women and to compare the labour outcome of GMP women who have undergone one previous Caesarean section (CS) with that of GMP women who never had a previous CS.MethodsThis prospective cohort study (Canadian Task Force Classification II-2) evaluated induction of labour with 1 mg of PGE₂ gel in 96 GMP women with one previous CS (study group) and in 104 GMP women without previous CS (control group).ResultsOne uterine rupture occurred in the study group (1%), and another occurred in the control group (0.9%). Additional oxytocin was used in seven patients (7.3%) in the study group and in 28 others (26.9%) in the control group (P = 0.002). Both uterine ruptures occurred with oxytocin augmentation. One case of uterine scar dehiscence was found in the study group. There was no significant difference between the study group and the control group regarding the rate of vaginal delivery (74 [77.1%] vs. 78 [75%]) or the rate of CS (21 [21.9%] vs. 24 [23.1%]), respectively. There was no significant difference between the groups in 5-minute Apgar scores ≤7. There was no neonatal death in either group.ConclusionA low dose (1.0 mg) of PGE₂ gel for induction of labour in GMP women with one previous CS is appropriate and appears to be safe for both mother and baby. Augmentation by oxytocin should be used judiciously.     

Prostaglandin induced cervical ripening under tocolytic cover in primiparae: results of a double blind placebo controlled trial

Summary. In a double blind trial, 60 nulliparae with a modified Bishop score of 5 requiring induction of labour, received either 8 mg of salbutamol or an identical placebo orally, 30 min before vaginal administration of 2 mg prostaglandin E₂ gel. Women in the salbutamol group experienced less uterine activity over the subsequent 12 h compared with those given placebo, and fewer (35%) commenced labour compared with the placebo group (62%). However, the change in cervical score was significantly less in the salbutamol group (mean 3.0, SD 3.1) than that in the placebo group (mean 5.8, SD 3.2), and the prostaglandin treatment to delivery time in the salbutamol group (mean 26.1 h, SD 6.49) was significantly longer than that in the placebo group (mean 19.3 h, SD 7.95). The first stage of labour lasted >10h in 11 women in the salbutamol group compared with five in the placebo group. Side effects attributable to salbutamol occurred in 10% > of the treated women but in none of their fetuses and fetal outcome was satisfactory and similar in both groups. Our findings show that salbutamol can suppress prostaglandin-induced uterine activity during cervical ripening, which could be an advantage in induction of labour where a planned delivery is preferred. However, the poorer outcome of labour in salbutamol-treated women mitigates against this approach.     

Prostaglandin induced cervical ripening under tocolytic cover in primiparae: results of a double blind placebo controlled trial

In a double blind trial, 60 nulliparae with a modified Bishop score of less than or equal to 5 requiring induction of labour, received either 8 mg of salbutamol or an identical placebo orally, 30 min before vaginal administration of 2 mg prostaglandin E2 gel. Women in the salbutamol group experienced less uterine activity over the subsequent 12 h compared with those given placebo, and fewer (35%) commenced labour compared with the placebo group (62%). However, the change in cervical score was significantly less in the salbutamol group (mean 3.0, SD 3.1) than that in the placebo group (mean 5.8, SD 3.2), and the prostaglandin treatment to delivery time in the salbutamol group (mean 26.1 h, SD 6.49) was significantly longer than that in the placebo group (mean 19.3 h, SD 7.95). The first stage of labour lasted greater than 10 h in 11 women in the salbutamol group compared with five in the placebo group. Side effects attributable to salbutamol occurred in 10% of the treated women but in none of their fetuses and fetal outcome was satisfactory and similar in both groups. Our findings show that salbutamol can suppress prostaglandin-induced uterine activity during cervical ripening, which could be an advantage in induction of labour where a planned delivery is preferred. However, the poorer outcome of labour in salbutamol-treated women mitigates against this approach.     

Induction of labour with prostaglandin E2 vaginal gel in women with one previous caesarean section

ObjectiveTo study the outcome of induction of labour with prostaglandin E2 (PGE2) vaginal gel in those with one previous caesarean section.DesignOne year prospective comparative study.SettingA tertiary care Armed Forces Hospital, Muscat.PopulationForty-six women with one previous caesarean section (CS) underwent PGE2 vaginal gel induction (study group). Hundred women with previous CS had gone into spontaneous onset of labour (control group).Main outcome measuresPrimary outcome measures are mode of delivery and uterine rupture. Others are neonatal outcome, indications for caesarean section, and complications like, postpartum haemorrhage and infectious morbidity.ResultsOverall rate of vaginal delivery after caesarean section (VBAC) was 65.21% and 79% in the study and control groups, respectively. There were 7 cases of neonatal intensive care unit (NICU) admissions (7%) in the control group; however, none in the study group. Caesarean section done for foetal distress was 5/16 CS in the study group (31.25%) and 10/21 CS in the control group (47.61%). There were no cases of uterine rupture in both control and study groups.ConclusionInduction of labour with prostaglandin E2 vaginal gel in women with one previous caesarean section does not significantly increase the risk of caesarean section rate or ruptured uterus and does not adversely affect immediate neonatal outcome.     

Evaluation of endocervical, first-void urine and self-administered vulval swabs for the detection of Chlamydia trachomatis in a miscarriage population

BACKGROUND: The issues related to safety of induction of labour in women with previous caesarean section remain controversial. The main adverse outcome fuelling this debate is a "small" risk of uterine rupture that is potentially devastating for both the mother and the fetus. OBJECTIVE: To estimate the risk of uterine rupture or dehiscence in women who require induction of labour with previous caesarean sections. DESIGN: Five year retrospective review of computerised hospital records and case note review of index cases. SETTING: Large inner city teaching hospital. POPULATION: Two hundred and five women who had their labour induced with history of one lower segment caesarean section. METHODS: This study was conducted at Liverpool Women's Hospital, a tertiary referral centre, with approximately 6000 births per annum. We searched the hospital's computerised records of deliveries from June 1997 to June 2002 and reviewed all indications and outcomes of induction of labour in women with one previous caesarean section. Women with singleton pregnancy and cephalic presentation were then divided into three groups: those with one previous caesarean section and no previous vaginal deliveries, those whose last delivery was a caesarean section but had delivered vaginally before and those whose last delivery was by vaginal route, but had had one caesarean section in the past. MAIN OUTCOME MEASURES: Uterine rupture or dehiscence, adverse neonatal outcome. RESULTS: Two hundred and five women were included. There were four cases of uterine rupture and one dehiscence (2.4%, 95% CI 0.8-5.6%). Two babies were profoundly acidotic at birth, but all five neonates were healthy when discharged from hospital with no long term morbidity. All five cases occurred in the group of women with no previous vaginal deliveries. The intrauterine pressure catheter recordings had contributed to the diagnosis of uterine rupture/dehiscence in three out of five cases. CONCLUSION: In women with previous caesarean section and no vaginal deliveries, induction of labour carries a relatively high risk of uterine rupture/dehiscence despite all precautions, including intrauterine pressure monitoring.     

Induction of labour after 1 previous Caesarean section

The aim of this study was, after induction of labour in women with a previous Caesarean section, to compare the outcome in women with a history of a previous vaginal delivery with women who had never delivered vaginally. A retrospective analysis was performed over a 2-year period, in a Dublin teaching hospital. One hundred and three women who had had 1 previous lower segment Caesarean section had labour induced. Particular attention was given to delivery outcome, history of a vaginal delivery, cervical effacement at induction, influence of epidural analgesia, indication for induction and incidence of uterine rupture. The repeat Caesarean section rate after induction was 20.4%. Of the 51 women who had never previously delivered vaginally, the repeat section rate was 37.3% compared with only 3.9% of the 52 women who had previously delivered vaginally (p < 0.01). Fourteen women who had never delivered vaginally had an uneffaced cervix at induction and the repeat Caesarean section rate in this group was 64.3%. The commonest indication for induction was a postdates pregnancy. The use of epidural analgesia was greater in women who had never delivered vaginally. There were 2 cases of uterine scar rupture. Induction of labour following Caesarean section is associated with a significantly higher incidence of repeat Caesarean section in women who have not had a previous vaginal delivery. If the cervix is not effaced at induction, the repeat Caesarean section rate is higher than if the cervix has started to efface.     

Factors associated with rapid labour in nulliparae.

The objective of this study was to assess the factors which may influence rapid labour in nulliparae. This is a cohort study of 991 consecutive nulliparae who were admitted in spontaneous labour with a singleton pregnancy and cephalic presentation. The setting was the National Maternity Hospital, Dublin where active management of labour is applied to all nulliparae fitting the above criteria. Rapid labour of 2 hours or less occurred in 82 patients (8.3%). Dilatation of 2 cm of the cervix on admission in labour, gestation of less than 37 weeks, and diminishing birthweight, were more common in rapid labours compared with other labours. Women in rapid labour were not surprisingly less likely to require oxytocin augmentation, or to need operative vaginal delivery or Caesarean section, receive epidural anaesthesia, or attend antenatal classes, compared with other women in labour. Rapid labour was not influenced by the finding that the membranes were already ruptured before admission, the time spent at home with contractions, or social background. Women with rapid labour were more likely to arrive in hospital within 4 hours compared with other women in labour. Rapid labour depends on the efficiency of uterine action which is reflected by the dilatation of the cervix on admission.     

The timing of amniotomy, oxytocin and neuraxial analgesia and its association with labour duration and mode of birth

Purpose

The objective was to study the association of different timings of intrapartum interventions with labour duration and mode of birth.

Methods

A longitudinal cohort study of 2,090 nulliparae and 1,873 multiparae with a singleton in cephalic presentation was conducted. We assessed the association between, on the one hand, the timing of augmentation with oxytocin, neuraxial analgesia and amniotomy, and, on the other hand, the time to complete dilatation, spontaneous or operative vaginal delivery or caesarean delivery, using a Cox regression model accounting for standard confounders.

Results

From amniotomy onwards labour was accelerated. In multiparae, amniotomy was associated with an initial 6.6-fold acceleration, decreasing first stage duration until the hazard ratio reached around 3.5, where the intervention was performed 5 h after labour onset; thereafter, acceleration continued with a hazard ratio of around 3. In nulliparae, neuraxial analgesia was associated with a shorter first stage when administered between 7 and 11 h after labour onset; the later it was performed, the less likely was spontaneous birth and the more likely an operative vaginal birth in nulliparae or a caesarean section in multiparae. The start of oxytocin augmentation was associated with acceleration towards both full dilatation and caesarean section during first stage and an increased risk of operative vaginal birth during second stage. The later oxytocin augmentation started, the more likely it was that spontaneous birth would be retarded in multiparous women.

Conclusions

Applying amniotomy, oxytocin and neuraxial analgesia at their optimal timing may improve the progress and outcome of labour.     

Prelabour rupture of membranes at term: early induction of labour versus expectant management

Objectives: To compare expectant management with early induction of labour in pregnant patients with prelabour rupture of membranes at term and unfavourable cervix. Study design: A prospective, randomised study of 154 women with prelabour rupture of membranes at term of whom 80 had been managed expectantly, and 74 had undergone oxytocin induction at a rate of 2.5 mU/min. Digital examination was not performed before oxytocin infusion, and the first was delayed until 4 h (nulliparae), or 2 h (multiparae) of regular uterine contractions. Results: The mean period from rupture of membranes to delivery was significantly shorter in the induction group. The mean duration of labour was significantly shorter in the expectant group. Operative vaginal deliveries were more common in the induction group, and fetal distress was the most common cause of operative vaginal deliveries. The caesarean rates were low and similar in both groups. Maternal and neonatal infectious morbidity was similar and no difference was found in the length of hospitalisation. Conclusions: Expectant management in patients with ruptured membranes at term is safe and reduces the frequency of operative vaginal deliveries.     

Effect of previous vaginal delivery on the risk of uterine rupture during a subsequent trial of labor

OBJECTIVE: We examined the effect of prior vaginal delivery on the risk of uterine rupture in pregnant women undergoing a trial of labor after prior cesarean delivery. STUDY DESIGN: The medical records of all pregnant women with a history of cesarean delivery who attempted a trial of labor during a 12-year period at a single center were reviewed. For the current analysis, the study population was limited to term pregnancies. The effect of previous vaginal delivery on the risk of uterine rupture during a subsequent trial of labor was evaluated. Separate analyses were performed for women with a single previous cesarean delivery and for those with >1 prior cesarean delivery. For each of these subgroups, the rate of uterine rupture among women who had > or =1 prior vaginal delivery was compared with the rate among women with no prior vaginal delivery. Logistic regression analysis was used to examine the associations with control for confounding factors. RESULTS: Of 3783 women with 1 prior scar, 1021 (27.0%) also had > or =1 prior vaginal delivery. During a subsequent trial of labor, the rate of uterine rupture was 1.1% among pregnant women without prior vaginal delivery and 0.2% among pregnant women with prior vaginal delivery (P =.01). Logistic regression analysis controlling for duration of labor, induction, birth weight, maternal age, year of birth, epidural analgesia, and oxytocin augmentation indicated that, among women with a single scar, those with a prior vaginal delivery had a risk of uterine rupture that was one fifth that of women without a previous vaginal delivery (odds ratio, 0.2; 95% confidence interval, 0.04-0.8). In the group of 143 pregnant women with >1 previous cesarean delivery, women with a prior vaginal delivery had a somewhat lower risk of uterine rupture (3.9% vs 2.5%; adjusted odds ratio, 0.6; 95% confidence interval, 0.01-6.7). This difference was not statistically significant. CONCLUSION: Among women with 1 prior cesarean delivery undergoing a subsequent trial of labor, those with a prior vaginal delivery were at substantially lower risk of uterine rupture than women without a previous vaginal delivery.     

PGE2 gel for enhancement of priming and induction of labour at term in patients with unfavorable cervix

Fifty women (25 nulliparae and 25 multiparae) with unfavourable cervix at term were enrolled in a clinical experiment to evaluate the safety and efficacy of the intracervical application of 0.5 mg PGE₂ gel for cervical softening and eventual induction of labour; duration of pregnancy (38–42 wk) was confirmed by ultrasonic records. Global analysis revealed 48 (96%) vaginal deliveries, 43 (86%) being spontaneous labour and 5 (10%) instrumentally assisted deliveries (forceps). Caesarean section was required in 2 cases (4%). Three patients, having registered no Bishop score (above 5) progress after the first treatment, went into labour upon the second application of PGE₂ gel. Mean induction-delivery time was 11 h 50 min for nulliparae and 7 h 50 min for multiparae. Mean ROM/amniotomy-delivery time was 5 h 59 min for nulliparae and 3 h 11 min for multiparae. Four neonates with initial Apgar scores below 7 registered immediately higher values after adequate reanimation manouvres.     

An Audit of Labour Following Caesarean Section at the Aga Khan Medical Centre

Summary: An audit of labour following Caesarean section was carried out over a 70-month-period to assess our management of labour following Caesarean section and to support the hospital quality assurance review progress for obstetric care: 419 patients with 1 previous Caesarean section were given a trial of labour: 314 (75%) women had a vaginal delivery and 105 (25%) had a repeat Caesarean section. The highest failure rate was observed in women whose previous indication for Caesarean section was cephalopelvic disproportion. There were 6 (1.4%) cases of scar dehiscence and 4 (1%) of uterine rupture. Vaginal delivery following Caesarean section is a viable cost-effective, safe procedure in a high quality labour and delivery unit in a developing country.