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Early amniotomy and early oxytocin for prevention of, or therapy for, delay in first stage spontaneous labour compared with routine care

RHL Commentary by Amorim M

1. INTRODUCTION

Caesarean section rates are rising worldwide and there is growing concern that in many cases caesarean section is performed simply because labour is deemed not to be progressing quickly enough. In Latin America, between 15% and 32% of all caesarean deliveries are attributed to dystocia (1). High rates of caesarean section do not necessarily indicate better maternal or perinatal care and can be associated with harm (2, 3).

Active management of first stage of labour, which involves early amniotomy and oxytocin augmentation, aims to reduce both the duration of labour as well as the incidence of prolonged labour. It has been suggested that active management of first stage of labour may help to reduce the caesarean section indication for dystocia and prolonged labour and could be employed as a strategy for reducing caesarean section rates, especially in countries where diagnoses of dystocia and prolonged labour are associated with high caesarean rates in nulliparous women.

The present review (4) assesses the effects of early amniotomy with early oxytocin administration "for the prevention of, or the therapy for, delay in labour progress on the caesarean birth rate and on indicator of maternal and neonatal morbidity".

2. METHODS OF THE REVIEW

The authors carried out a comprehensive search, without any language restriction, to identify trials from the Cochrane Pregnancy and Childbirth Group’s Trial Register, MEDLINE, EMBASE, CINAHL and MIDIRS (November 2008). The selection criteria for studies included both randomized and quasi-randomized controlled trials that had compared oxytocin and amniotomy with routine care. The analysis was stratified into "prevention trials" and "therapy trials" according to the status of the woman at the time of randomization. Participants in the prevention trials were unselected women, without slow progress of labour, who were randomized to a policy of early augmentation or to routine care. In treatment trials, women were eligible if they had an established delay in the progress of labour. The primary outcome studied was caesarean section rate, and secondary outcomes included types of delivery (spontaneous or instrumental), duration of labour, maternal satisfaction with the intervention, potential adverse effects and perinatal outcomes (Apgar score, acidosis, abnormal fetal heart rate tracing, admission to special care nursery and jaundice). A fixed-effect meta-analysis was used for the main outcomes. A sensitivity analysis was carried out to explore the effects of the policy of early amniotomy and oxytocin alone, without the full package of co-interventions usually considered as active management.

3. RESULTS OF THE REVIEW

A total of 12 trials involving 7792 women were included. Ten trials had enrolled women who were in spontaneous labour at randomization. In these trials, women were randomized either to early amniotomy and oxytocin or to routine care. These studies were termed "prevention trials". Two trials that included only women with an established abnormality in the progress of labour were grouped as "treatment trials".

Eleven trials recruited nulliparous women, whereas one trial included both nulliparous and multiparous women. Active management of the first stage of labour was studied in three trials in which in the experimental arm of the trial strict criteria were applied for the diagnosis of labour, performance of early amniotomy, prompt administration of oxytocin (with high-dose oxytocin being administered in the event of insufficient uterine action) and continuous professional support

In all studies, if the membranes were intact, the more interventionist policy consisted of early amniotomy and early oxytocin infusion. Oxytocin was used in women in the control groups if there was a more marked delay in the progress of labour. In the control groups, in case of delay in the progress of labour, amniotomy and oxytocin augmentation were performed and the rationale for provision of these interventions ranged from use of amniotomy and oxytocin augmentation as part of continued usual care to performance of the interventions after an eight-hour period of expectant management following randomization.

Unstratified analysis revealed that early intervention with amniotomy and oxytocin was associated with a statistically non-significant, modest reduction in the risk of caesarean section [risk ratio (RR) 0.89; 95% confidence interval (CI) 0.79–1.01)].

In the 10 prevention trials (7653 women), early augmentation was associated with a marginally statistically significant reduction in the number of caesarean births (RR 0.88; 95%CI 0.77–0.99). The difference in caesarean risk was 1.47%, implying that to prevent one case of caesarean section 68 women would have to be treated with active management of the first stage of labour (number needed to treat = 68). On the other hand, the two treatment trials did not yield a clear result: the number of participants was small and there was a wide confidence interval related to the result (139 women; RR 1.54; 95% CI 0.75–3.15). Sensitivity analyses, excluding the three trials with a full package of active management of the first stage of labour, did not substantially affect the point estimate of the effect (RR 0.87; 95% CI 0.73–1.04).

A policy of early amniotomy and early oxytocin was associated with a shortened duration of labour (mean difference –1.11 hour, CI -1.82 to -0.41). Though all the trials investigating this outcome showed a trend towards shortening the duration of labour, this finding was affected by considerable heterogeneity between trial results.

There was no evidence of any effect of early amniotomy and oxytocin for other maternal outcomes, such as spontaneous delivery (RR 1.01; 95% CI 0.97–1.05), instrumental vaginal delivery (RR 1.01; 95% CI 0.92–1.11) and use of epidural analgesia (RR 1.05; 95% CI 0.99–1.12). No differences were found between early amniotomy plus oxytocin groups and control groups with respect to fetal/neonatal morbidity and mortality.

The trials did not provide sufficient evidence with regard to other indicators of maternal or neonatal health, including women’s satisfaction and views on the experience.

4. DISCUSSION

4.1 Applicability of the results

The review concludes that, compared with routine care, the policy of early amniotomy and oxytocin augmentation for the prevention and treatment of delays in the progress of labour results in modest reductions in caesarean section rates (difference in risk of 1.47%) and the duration of labour (about 70 minutes). The magnitude of reduction in caesarean section rates achieved is unlikely to change significantly the incidence of caesarean sections in most countries. The rise in caesarean section rates worldwide can be explained by other factors than management of prolonged labour. In Latin America, emergencies represent only 6% or less of caesarean deliveries (1). In Brazil, for instance, dystocia is responsible for 15% of caesarean sections (1), but evidence suggests that elective caesarean delivery is becoming more frequent (2) and non-medical factors are associated with a significant percentage of caesarean deliveries (5, 6).

Therefore, in most settings it would be important to analyse the primary local and regional reasons for existing caesarean section rates before deciding to implement this intervention to reduce caesarean section rates. Furthermore, complications related to active management of the first stage of labour are not well documented in this review. Hyperstimulation of labour, for instance, was described in two trials only and a trend towards increased risk, although not statistically significant, was found.

Finally, it is not clear if shortening the duration of labour is a desirable objective, mainly in terms of women's perception of the duration. The effects of labour augmentation on pain were not studied and pain reduction in labour can become a preoccupation for many women in labour. Clearly, more information is required about women’s perceptions of early intervention in cases of prolonged labour. Considering all of the above, there is no justification at the present time to apply as a routine practice the policy of early labour augmentation for reducing caesarean sections or prolonged labour in either developed or developing countries.

4.2 Implementation of the intervention

In settings where a large proportion of caesarean deliveries is related to prolonged labour, active management of the first stage of labour could be considered as an additional strategy for reducing the duration of labour and, possibly, lowering the rates of caesarean section. However, before implementing such a policy, health-care facilities should carefully evaluate the local context and determinants of prolonged labour, such as misdiagnosis of latent stage of labour (i.e. women diagnosed as being in the first stage labour while they are still in the latent phase). If a facility has a high caesarean sections rate, the primary indications and other reasons for caesarean sections should be considered first. Anyway, women should be informed of the possible benefits of early intervention by amniotomy and oxytocin to reduce risk of caesarean deliveries, but the possible effects on shortening of labour and other complications must be clarified. Women whose HIV status is unknown at delivery (especially in HIV high-prevalence settings) and women living with HIV/AIDS should not receive early amniotomy, in order to reduce the risk of HIV transmission to the infant

4.3 Implication for research

Further studies should be conducted to assess the risks and benefits of active management of first stage of labour. These studies should standardize diagnostic criteria for considering delay in the progress of labour. There is also a need for better information about the effects of administration of oxytocin alone, without rupture of membranes. More information is required about women’s perceptions of early intervention and the effects of early intervention on pain during labour. Maternal satisfaction should be assessed in further trials. Cost–benefit analysis should be undertaken to compare costs of active management of the first stage of labour versus routine treatment.

References

• Stanton C, Ronsmans C. Recommendations for routine reporting on indications for caesarean delivery in developing countries. Birth 2008;35: 204-211.
• Villar J, Valladares E, Wojdyla D, Zavaleta N, Carroli G, Velazco A, et al. for the WHO 2005 Global Survey on Maternal and Perinatal Health Research Group. Caesarean delivery rates and pregnancy outcomes: the 2005 WHO Global Survey on Maternal and Perinatal Health in Latin America. The Lancet 2006;367:1796-1797.
• Althabe F, Belizan JF. Caesarean section: the paradox. The Lancet 2006;368:1472-1473.
• Wei S, Wo BL, Xu H, Luo Z-C, Roy C, Fraser WD. Early amniotomy and early oxytocin for prevention of, or therapy for, delay in first stage spontaneous labour compared with routine care. Cochrane Database of Systematic Reviews 2009;Issue 2. Art. No.: CD006794; DOI: 10.1002/14651858.CD006794.pub2.
• Almeida S, Bettiol H, Barbieri MA, Silva Moura AA, Sousa RV. Significant differences in caesarean section rates between a private and a public hospital in Brazil. Cadernos de Saúde Pública 2008;24: 2909-2918 (in Portuguese).
• Potter JE, Hopkins K, Faúndes A, Perpétuo I. Women's autonomy and scheduled caesarean sections in Brazil: a cautionary tale. Birth. 2008;35:33-34

This document should be cited as: Amorim M. Early amniotomy and early oxytocin for prevention of, or therapy for, delay in first stage spontaneous labour compared with routine care : RHL commentary (last revised: 1 November 2009). The WHO Reproductive Health Library; Geneva: World Health Organization.