The timing of hospital admission and progress of labour

We set out to study the relationship between the timing of hospital admission and the progress of labour. In all there were 591 healthy primiparous women with normal pregnancies and who anticipated normal deliveries; 436 of them had come because of contractions. When the intrinsic speed of labour (estimated from the status of the cervix at the time of admission in relation to the duration of regular contractions) was allowed for, women coming early (regular contractions for 4 h or less before admission) as compared to those coming late stayed longer in the hospital before delivery but had a shorter total length of labour. They had more interventions during labour, more caesarean sections, longer postpartum hospital stay, and their children had more diagnoses of difficult delivery. Women who came because of ruptured membranes without contractions had shorter labours, more interventions during labour, longer postpartum stay and their children had more discharge diagnoses and longer hospital stay than women coming late. This study suggests that too early admission to the hospital may negatively affect the progress of labour, and controlled trials are needed to confirm or to disprove this suggestion.     

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.     

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.     

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

Summary. 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 multiparac 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.     

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.     

Cervical ripening with dehydroepiandrosterone sulphate

Summary. Dehydroepiandrosterone sulphate (DHEA-S) was given intravenously twice a week after 38 weeks gestation to ripen the uterine cervix in 20 nulliparae and 24 parous women who subsequently went into labour at term. The condition of the uterine cervix was assessed by Bishop scoring. The increase in the score in nulliparous women given DHEA-S was significantly greater than that in the control group, who were given placebo injections, on the 7th, 14th and 21st days. The increase in the parous women was significant only on the 7th day. In nulliparous women the dilatation, effacement and consistency improved significantly, while in the parous women the effect of DHEA-S was apparent only in the consistency. The duration of labour was significantly shortened by treatment with DHEA-S in nulliparae but this effect was not found in parous women. The interval between the first administration of DHEA-S and the onset of labour in nulliparae was significantly shorter than that in the control group. There were no serious side effects or complications. Our results suggest that DHEA-S may be used safely and effectively to ripen the uterine cervix and to trigger the onset of labour in late pregnancy.     

Premature rupture of the membranes at term. Obstetric outcome with oxytocin stimulation in relation to parity and cervical dilatation at admission

The obstetric outcome in women with premature rupture of the membranes (PROM) at term (greater than 36 weeks gestation) without spontaneous onset of labor (within 2 h after admission) was evaluated prospectively in a joint study at the University Hospital of Lund, Sweden and Kandang Kerbau Hospital, National University of Singapore. After 2 h of observation without uterine contractions, labor was stimulated with oxytocin infusion. 303 patients participated and were classified according to parity (nulliparae-multiparae) and cervical dilatation at admission (less than 2 cm dilated; greater than or equal to 2 cm dilated). No significant race-related differences could be found, except for birthweight. Nulliparae with unfavorable cervix at admission had a high rate of ominous fetal heart rate findings in labor and a high cesarean section rate (19.4%), particularly for failed stimulation of labor. The high cesarean section rate after routine stimulation of labor in nulliparae with unfavorable cervix suggests that a non-intervention approach may be justified in this group. In contrast, the cesarean section rate after stimulation of labor was 3.6% in nulliparae with the cervix dilated 2 cm or more at admission and 4.2% in multiparae and ominous fetal heart rate changes were much less common.     

Factors associated with preterm labour and changes in the cervix before labour in twin pregnancy

Summary. A total of 132 twin pregnancies in black African women were studied prospectively after 30 weeks gestation. Delivery occurred before 37 weeks in 32%. There was a trend (0.1 > P > 0.05) towards a higher preterm delivery rate in nullipara (57%), in women under the age of 20 years (60%) and in those with a height/weight ratio of >2.5 (50%). The cervix was assessed with a score based on the length of the canal minus the dilatation of the internal os. In both term and preterm labour there was a significant relation between a cervical score of 0 or a decrease in cervical score and the onset of labour within the subsequent 14 days ( P < 0.001). By these criteria to predict impending labour, 60% of all labours that ensued within 14 days of the assessment would have been predicted with a 20% false positive rate. When nulliparae were excluded the predictive value of cervical assessment for preterm labour was 80% with a false positive rate of < 5%. Plasma oestriol levels were significanty higher in the preterm labour group but had no clinical prognostic value.     

Induction of labour with a favourable cervix and/or pre-labour rupture of membranes

Premature rupture of membranes (PROM) occurs in 8% of term deliveries. In this situation labour induction with prostaglandins, compared with expectant management, results in a reduced risk of chorioamnionitis, neonatal antibiotic therapy, neonatal intensive care (NICU) admission, and increased maternal satisfaction. The use of prostaglandin is associated with an increased rate of diarrhoea and use of analgesia/anaesthesia. Compared with oxytocin, prostaglandin induction results in a lower rate of epidural use and internal fetal heart rate monitoring but a greater risk of chorioamnionitis, nausea, vomiting, more vaginal examinations, neonatal antibiotic therapy, NICU admission and neonatal infection. Women should be informed of the risks and benefits of each method of induction.Misoprostol is gaining increasing interest as an alternative induction agent. It appears to be an effective method of labour induction with term PROM. Further research is needed to identify the preferred dosage, route and interval of administration, and to assess uncommon maternal and neonatal outcomes.There has been limited research on the use of prostaglandins, including misoprostol, for induction of labour with a favourable cervix and intact membranes. Compared with intravenous oxytocin (with and without amniotomy), labour induction using vaginal prostaglandins in women with a favourable cervix (with and without PROM) results in a higher rate of vaginal delivery within 24 hours and increased maternal satisfaction. In women with a favourable cervix, artificial rupture of membranes followed by oral misoprostol has similar time to vaginal delivery compared with artificial rupture of membranes followed by oxytocin. Further research with prostaglandins, including misoprostol, is needed to evaluate other maternal and neonatal outcomes in women being induced with a favourable cervix.No form of prostaglandin induction in women with PROM or favourable cervix has proven clearly superior to oxytocin infusion.     

Characteristics of normal labour in different racial groups.

The characteristics of normal labour in 1306 white, Asian and black parturients have been established following a prospective study of 3217 consecutive labours. Asian patients were found to be of significantly shorter stature than white or black women (p less than 0-001) and their infants significantly lighter than those of white (p less than 0-001) and of black (p less than 0-05) women, and a low positive correlation was found between maternal height and infant birth weight. The mean duration of the first stage of labour, taken from the time of admission to the labour ward, was 5-6 hours in primiparae and 3-7 hours in multiparae. The mean durations of the second stage of labour were 41-5 and 17-4 minutes respectively. The correlations between the duration of the first and second stages of labour were too low to be of value in patient management. Similar low correlations were found between the duration of the second stage of labour and both infant birth weight and the Apgar score at one minute. Cervical dilatation-time curves, constructed with reference to the cervical dilatation found on admission to the labour ward, revealed no significant differences in the progress of normal labour in the different racial groups.     

The benefits and risks of inducing labour in patients with prior caesarean delivery: a systematic review

OBJECTIVE: To evaluate the risks and benefits of inducing labour in women with a prior caesarean delivery. DESIGN: Systematic review. SAMPLE: Pregnant women with prior caesarean delivery. METHODS: Studies were identified using MEDLINE, EMBASE, HealthSTAR, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Abstracts of Reviews of Effectiveness, reference lists and experts. MAIN OUTCOME MEASURES: All studies reporting data for outcomes in women with induced labours and prior caesarean were eligible. Methodologic quality was evaluated using the criteria of the U.S. Preventive Services Task Force and the NHS Centre for Reviews and Dissemination. We assigned studies good, fair or poor rating. RESULTS: We reviewed 162 full text articles, identified 14 fair-quality studies, and found no good-quality studies. Compared with spontaneous labour, induction was more likely to result in caesarean delivery. Of women undergoing spontaneous labour, 20% had a caesarean (range 11-35%) compared with 32% receiving oxytocin (range 18-44%). In studies of PGE2, spontaneous labour resulted in caesarean delivery in 24% (range 18-51%) compared with 48% with PGE2 (range 28-51%). There was a non-significant increase in uterine ruptures among those induced compared with spontaneous labours. There were no maternal deaths; other maternal complications were infrequently reported. Only four studies reported on infant deaths; other infant outcomes were inadequately reported. CONCLUSION: Women with a history of caesarean attempting trial of labour who require induction have a higher rate of caesarean delivery and have a slightly elevated risk of rupture compared with similar women with spontaneous labour. More consideration is needed for potential confounders: dose, reasons for induction and appropriate comparison groups.     

The relation of time of day to childbirth

Abstract

Study 1 examined the case notes of 105 primiparous and 42 multiparous women in order to assess the relation of time of day to onset of labour, length of labour and epidural and augmentation administration. Results showed that primiparous mothers who consciously experienced their first contractions at night had shorter labours than those who began labour during daytime. In addition, the study revealed that the majority of epidural and augmentation administration occurred during daytime working hours. Study 2 aimed to replicate and expand on these results, and investigated whether shorter nocturnal labours were due to mothers sleeping through the mild contractions at the onset of labour, and whether the increase in epidural and augmentation administration was due to an increase in staffavailability during daytime working hours. The results showed that there was a longer latency between admission to labour ward and augmentation and/or epidural administration during night shift in comparison to day shifts, implying that midwives may employ stricter criteria at night before deciding that a labour should be augmented/anaesthetized. Measures failed to clarify why nocturnal labours were shorter than daytime labours, due to several confounding variables.     

Misoprostol versus dinoprostone for cervical priming prior to induction of labour in term pregnancy: a randomised controlled trial

A prospective randomised controlled trial was performed to compare the efficacy and safety of intravaginal misoprostol to that of intravaginal dinoprostone when used for cervical priming prior to the induction of labour; 126 women were recruited to the study and randomised to receive either intravaginal dinoprostone (n = 63) or misoprostol (n = 63) for cervical priming prior to induction of labour. The mean time from insertion of the priming agent to vaginal delivery was significantly shorter in the misoprostol group (925.8 versus 1577.6 minutes), the mean duration of the active length of labour was significantly shorter in the misoprostol group (353.7 versus 496.8 minutes) and more women in the misoprostol group delivered in less than 12 hours (92% versus 76.5%). Women in the misoprostol group were less likely to require a repeated dose of prostaglandin for cervical priming and less likely to require oxytocin for augmentation of labour. There was no difference in the number of women who were delivered vaginally or by Ceasarean section between the two groups. More women developed hyperstimulation during labour in the misoprostol group; however there was no difference between the groups in neonatal outcome in respect to low cord pH or Apgar score at delivery or admission to the neonatal special care nursery.     

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.     

Prelabour Rupture of the Membranes at Term-No Advantage of Delaying Induction for 24 Hours

We performed a prospective randomized study to compare maternal and fetal outcomes in pregnancies with prelabour rupture of the membranes (PROM) at term with early induction of labour or expectant management, 126 women with singleton pregnancy, cephalic presentation and gestational duration > or = 37 weeks, were randomized either to immediate induction of labour with oxytocin (Group 1) (n=52), or conservative management (Group 2) (n=74). Women who constituted Group 2 were divided into 2 groups. The first group (Group 2A) (n=25) included women in whom spontaneous labour did not begin after a waiting period of 24 hours, in which case labour was induced with oxytocin i.e. expectant management. The second group consisted of women (Group 2B) (n=49) in whom labour began spontaneously within 24 hours. The base Caesarean section rate was significantly higher in Group 2 (28.4%) (p<0.05). The rates of Caesarean section in the Groups 1-2A-2B were 19.2%, 60%, and 12.2%, respectively for nulliparous and parous women together. The rate of fetal distress was significantly higher in Group 2 (p<0.05). For determining maternal outcomes, the other parameters such as clinical chorioamnionitis, fever before or during labour, receiving antibiotics before or during labour, postpartum fever, analgesia, anaesthesia did not differ in Groups 1 and 2. Women in Group 1 went into active labour sooner, had fewer digital vaginal examinations, had a shorter interval between membrane rupture and delivery, and spent less time in the hospital before delivery than those in Group 2 (p<0.05). Babies in Group 2 were more likely to receive antibiotics, and more likely to stay in an intensive care nursery for more than 24 hours, and more likely to receive ventilation after initial resuscitation than those babies in Group 1. For developing apnoea and hypotonia, there was no significant difference between Groups 1 and 2. However, for babies in Group 2A there was a significant difference. We conclude that immediate induction of labour with oxytocin does not increase the risk of Caesarean section, compared with a practice of expectant management. Women at term with prelabour rupture of the membranes should therefore be reassured that immediate induction with oxytocin currently appears to be the best policy with respect to maternal and neonatal morbidity.     

Intrapartum pain management at the Royal Hospital for Women

AIMS: To explore use of, and women's satisfaction with, intrapartum pain management at Royal Hospital for Women (RHW), Sydney, Australia. METHODS: From October 2002 to January 2003 women aged over 16 who had been in labour at RHW were given a questionnaire to complete in the first week post-partum regarding their intrapartum pain management. Supplementary information was obtained from patient records. RESULTS: A total of 496 women participated (69% response rate), including 95 birth centre clients. The mean age was 32 years and 73% percent had a normal vaginal delivery. At least one form of pain management ('natural', nitrous oxide, pethidine, epidural, local infiltration of the perineum) was used by 463 (93%) women, with 74% using two or more methods. Labour pain was 'worse' or 'much worse' than expected for 55%. Seventy-two percent were 'very' or 'quite' satisfied with overall pain management. Epidural analgesia had the highest utility scores (89%'very useful') and likelihood of use in subsequent labours (67%), and pethidine the lowest. Factors affecting analgesic use included cervical dilation on admission, labour length, English-speaking background, delivery suite versus birth centre care, parity, and syntocinon use. CONCLUSIONS: Women at RHW use a variety of pain management methods in labour and most use multiple methods. Labour was rated more painful than expected by a majority; however, most were satisfied with their pain management. Labour length and cervical dilation on admission were most predictive of pain management use.     

The multigravid partogram--should it be customised?

Multigravid labour is conducted according to an alert line and an action line derived from primigravid spontaneous labour. Although it is widely recognised that multigravid labour is significantly faster than primigravid labour, the standard of care for both is the 'usual-care' partogram. A series of 1398 partograms of spontaneous multigravid labours resulting in vaginal delivery was audited. Retrospectively, the labours were graphed on a usual-care and on a customised partogram. The customised alert line was built to represent the rate of cervical dilataion of the lower 90 per cent. (after excluding the 10 per cent of very rapid labours.) The effect of putting the action line 2, 3 or 4 hours behind the alert line on the relative distribution of labours was tested. The results indicate that the norms of the usual-care partogram do not reflect the facts of multigravid labour.     

Duration of labour with spontaneous onset.

Among 2242 women with spontaneous onset of labour, the median duration of labour for those delivered vaginally was 8 1/4 hours in para 0, 5 1/2 hours in para 1 and 4 3/4 hours in para 2+ mothers. In the parity groups 0, 1 and 2+ 90% had delivered within 16 1/4 hours, 10 1/2 hours and 10 3/4 hours, respectively, while 10% of para 0 labours lasted less than 4 hours, 10% of para 1 labours less than 2 1/4 hours and finally 10% of para 2+ labours less than 2 hours. In the first stage of labour the latent phase (cervical dilatation less than 4 cm), was nearly 2.5 times as long as the active phase (cervical dilatation 4-10 cm). The second stage (cervical dilatation 10 cm-birth) had a median duration of 16 min in para 0 and approximately 10 min in para 1+ mothers. The length of the latent and active phases and the second stage for para 1+ mothers was 60-70% of that of para 0 mothers. In individual mothers there were weak correlations between the length of the phases and stages. For example, the length of the latent phase appeared to be a relatively poor predictor of the length of the active phase of labour. However, selection bias may have weakened these correlations somewhat.     

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.     

The outcome of pregnancy after cone biopsy of the cervix: a case-control study

We investigated the outcome of pregnancy after cone biopsy of the cervix. We found that preterm delivery and low birth weight were commoner and the mean duration of labour longer in women who had a cone biopsy than amongst matched controls. Rapid labour (under two hours) was not significantly more common after cone biopsy.