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Background: Low-lying placentas are positioned close to the internal os of the cervix. The preferred way of delivery within this group is unclear. Objectives: To review the literature on the success of a vaginal delivery with a low-lying placenta. Search strategy: We searched OVID EMBASE and MEDLINE for studies on vaginal delivery with a low-lying placenta. Data collection and analyses: Data was extracted on successful vaginal delivery and emergency caesarean section due to haemorrhage. We distinguished between different distances between the cervical os and the placenta (internal os distance, IOD); 0–10, 11–20, and >20 mm. A meta-analysis of proportions was made for successful vaginal delivery and emergency caesarean section at every cut-off value. Maternal morbidity (i.e. antepartum blood loss, postpartum haemorrhage and blood transfusion) at different cut-off values was evaluated. Main results: Of the 999 articles retrieved, 10 articles met our inclusion criteria. A vaginal delivery was successful at an IOD of 0–10 mm in 43%, at an IOD of 11–20 mm in 85%, and at an IOD of >20 mm in 82%. A shorter IOD had a higher chance of antepartum haemorrhage, whereas a larger IOD needed postpartum blood transfusion more often. Postpartum haemorrhage did not depend on IOD. Conclusion: A low-lying placenta is not a contraindication for a trial of labour, and the morbidity in these women is not increased. However, women with a low-lying placenta have a higher chance of an emergency caesarean section compared with women with a placenta outside the lower uterine segment. Therefore, shared decision-making is mandatory in case of a trial of labour. Tweetable abstract: This systematic review demonstrates the possibility of a vaginal delivery in women with a low-lying placenta within 20 mm of the cervix.

Objective To investigate the association of chorioamnionitis and its duration with adverse maternal outcomes by mode of delivery. Design A retrospective cohort study. Setting Data from the Consortium on Safe Labor Study in the USA (2002-2008). Population Singleton deliveries at ≥23 weeks of gestation (221 274 assessed deliveries, 62 331 by caesarean section). Methods The association of chorioamnionitis, and secondarily the duration of chorioamnionitis estimated from intrapartum antibiotic use, with adverse maternal outcomes was analysed using logistic regression with generalised estimating equations, adjusting for age, parity, race, pregestational diabetes, chronic hypertension, gestational age at delivery, study site and delivery year. Analyses were stratified by vaginal versus caesarean delivery. Main outcome measures The composite adverse maternal outcome included: postpartum transfusion, endometritis, wound/perineal infection/separation, venous thromboembolism, hysterectomy, admission to intensive care unit and/or death. Results Chorioamnionitis was associated with higher odds of the composite adverse maternal outcome with caesarean delivery (adjusted odds ratio 2.31; 95% CI 1.97-2.71); and the association persisted regardless of whether a woman had a trial of labour, preterm delivery or maternal group B streptococcus colonisation. The most common adverse outcomes after caesarean section were postpartum transfusion (56.0%) and wound/perineal infection or endometritis (38.6%). Chorioamnionitis was not associated with adverse maternal outcomes after vaginal delivery. The duration of chorioamnionitis as the exposure did not alter the association between chorioamnionitis and adverse maternal outcomes. Conclusions Chorioamnionitis, but not the estimated duration, was associated with increased odds of adverse maternal outcomes with caesarean delivery. This finding has implications for care programmes to prevent maternal morbidity after a caesarean section complicated by chorioamnionitis. Tweetable abstract Chorioamnionitis, but not its duration, increases the risk of adverse maternal outcomes with caesarean delivery.

In this issue, Hautakangas et al report that "we found significantly lower intrauterine pressure (IUP) in failed Trial Of Labour After Caesarean (TOLAC), compared with Vaginal Birth After Caesarean", although "the dosages of oxytocin tended to be higher among failed TOLACs". They commented that "it seems that raising the oxytocin dosage does not necessarily improve uterine contractile activity in this group". Why is this?

Few studies have focused specifically on the intrapartum management of patients following a prior caesarean delivery. Contemporary assessments and recommendations on attempting vaginal birth after caesarean delivery (VBAC) vary. The actual conduct of labour and delivery of the infant in an uncomplicated trial of labour after caesarean (TOLAC) is similar to the management of a patient without a previous caesarean. Intrapartum management of TOLAC differs primarily in the need for caution with induction of labour in women with an unfavourable cervix, the avoidance of overstimulation with oxytocin augmentation, and surveillance for prompt recognition of the rare case of uterine rupture.

OBJECTIVE: To study perinatal mortality rates in a cohort of 465 monochorionic (MC) twins without twin-twin transfusion syndrome (TTS) born at 32 weeks of gestation or later since reported interauterine fetal death (IUFD) rates >32 weeks of gestations in the literature vary, leading to varying recommendations on the optimal timing of delivery, and to investigate the relation between perinatal mortality and mode of delivery. DESIGN: Multicentre retrospective cohort study. SETTING: Ten perinatal referral centres in the Netherlands. POPULATION: All MC twin pregnancies without TTTS delivered at >/= 32 weeks of gestation between January 2000 and December 2005. METHODS: The medical records of all MC twin pregnancies without TTTS delivered at the ten perinatal referral centres in the Netherlands between January 2000 and December 2005 were reviewed. MAIN OUTCOME MEASURES: Perinatal mortality in relation to gestational age and mode of delivery at >/= 32 weeks of gestation. RESULTS: After 32 weeks of gestation, five out of 930 fetuses died in utero and there were six neonatal deaths (6 per 1000 infants). In women who delivered >/= 37 weeks, perinatal mortality was 7 per 1000 infants. Trial of labour was attempted in 376 women and was successful in 77%. There were three deaths in deliveries with a trial of labour (8 per 1000 deliveries), of which two were related to mode of delivery. Infants born by caesarean section without labour had an increased risk of neonatal morbidity and respiratory distress syndrome. CONCLUSIONS: In MC twin pregnancies the incidence of intrauterine fetal death is low >/= 32 weeks of gestation. Therefore, planned preterm delivery before 36 weeks does not seem to be justified. The risk of intrapartum death is also low, at least in tertiary centres.

Objective In many developing countries, most women deliver at home or in facilities without operative capability. Identification before labour of women at risk of dystocia and timely referral to a district hospital for delivery is one strategy to reduce maternal and perinatal mortality and morbidity. Our objective was to assess the prediction of dystocia by the combination of maternal height with external pelvimetry, and with foot length and symphysis-fundus height. Design A prospective cohort study. Setting Three maternity units in Yaounde, Cameroon. Population A total of 807 consecutive nulliparous women at term who completed a trial of labour and delivered a single fetus in vertex presentation. Methods Anthropometric measurements were recorded at the antenatal visit by a researcher and concealed from the staff managing labour. After delivery, the accuracy of individual and combined measurements in the prediction of dystocia was analysed. Main outcome measures Dystocia, defined as caesarean section for dystocia; vacuum or forceps delivery after a prolonged labour (>12 hours); or spontaneous delivery after a prolonged labour associated with intrapartum death. Results Ninety-eight women (12.1%) had dystocia. The combination of a maternal height less than or equal to the 5th percentile or a transverse diagonal of the Michaelis sacral rhomboid area less than or equal to the 10th percentile resulted in a sensitivity of 53.1% (95% CI 42.7–63.2), a specificity of 92.0% (95% CI 89.7–93.9), a positive predictive value of 47.7% (95% CI 38.0–57.5) and a positive likelihood ratio of 6.6 (95% CI 4.8–9.0), with 13.5% of all women presumed to be at risk. Other combinations resulted in inferior prediction. Conclusion The combination of the maternal height with the transverse diagonal of the Michaelis sacral rhomboid area could identify, before labour, more than half of the cases of dystocia in nulliparous women.

Objective To compare the maternal implications of strategies of vaginal birth after caesarean section (VBAC) attempt versus elective repeat caesarean section in women with one previous lower segment caesarean section. Design Decision model. Population Women with one prior low transverse caesarean section who are eligible for trial of labour. Methods Two decision models were built: the first one applying to women planning only one more pregnancy, the second one applying to women planning two more pregnancies. Probability estimates for VBAC success rate and risks of uterine rupture, placenta praevia, placenta accreta and hysterectomy were extracted from the available literature. Main outcome measures Hysterectomy for uterine rupture, placenta accreta or other indications. Results In the first model VBAC attempt led to a higher hysterectomy rate (267/100,000) compared with repeat caesarean section (187/100,000). However, in the second model a policy of elective repeat caesarean section led to higher cumulative hysterectomy rate: 1465/100,000 versus 907/100,000 for VBAC. The first model was robust to all but one variable in sensitivity analyses. The second model was robust to all variables in sensitivity analyses. Conclusions These results indicate that long term reproductive consequences of multiple caesarean sections should be considered when making policy decisions regarding the risk–benefit ratio of VBAC.

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.

Objective To determine the outcome of trial of labour after two caesarean sections. Design Prospective observational study. Setting Maternity and Children's Hospital, Riyadh, Saudi Arabia. Subjects Women with two previous caesarean sections considered suitable for a trial of vaginal delivery. Main outcome measures The rates of vaginal delivery, scar dehiscence, uterine rupture and associated complications among 115 women with two previous sections who underwent trial of labour were compared with 1006 women with two previous sections who did not have a trial of labour. Results Trial of vaginal delivery was requested by 230 out of 1136 women (20%) who had two previous caesarean sections. Of the 115 women accepted for the trial, 103 (89%) were delivered vaginally. Labour started spontaneously in 78 (68%) of the 115 women and was induced with prostaglandin (PGE2) in the remaining 37. Augmentation of labour with oxytocin was required in 32 (28%) of the trial labour group. There were no scar dehiscences among the women delivered vaginally. There was one scar dehiscence and one woman required hysterectomy after failed trial of labour, a frequency comparable to the occurrence of these complications in women who did not have a trial of labour. Conclusion A trial of labour in selected patients with two previous caesarean sections appears a reasonable option.

OBJECTIVE To investigate the impact of uterine contractile activity on the outcome of trial of labour after caesarean section (TOLAC). DESIGN Secondary, blinded analyses of a prospective TOLAC cohort. SETTING Two labour wards, one in a university tertiary hospital and the other in a central hospital. POPULATION A total of 194 TOLAC parturients with intrauterine tocodynamometry during labour. METHODS Analysis of intrauterine pressure, frequency of contractions and baseline tonus of uterine muscle in 30-minute periods for 4 hours before birth. MAIN OUTCOME MEASURES Primary outcome: uterine contractile activity during TOLAC. Secondary aims: contributors associated with failed TOLAC and uterine rupture. RESULTS TOLAC succeeded in 74% of cases. Uterine contractile activity, expressed as intrauterine pressure, was significantly higher in successful TOLAC compared with failed TOLAC (210 versus 170 Montevideo units). The statistically significant risk factors of failed TOLAC, after multivariate regression analysis, were prolonged gestational age, reduced cervical dilatation at admission and lower mean intrauterine pressure. In cases of uterine rupture, contractile activity did not differ from that in failed TOLAC. Cervical ripening with a Foley catheter appeared to be a risk factor for uterine rupture, as well as cervical dilatation