Using the Nippita classification system for women undergoing induction of labour in a large metropolitan maternity service: Bringing simplicity and certainty to an important quality improvement process

Trends and characteristics of women undergoing induction of labour in a tertiary hospital setting: A cross-sectional study

BACKGROUND

In many well-resourced countries, rising rates of intervention are being observed during pregnancy, labour and childbirth with induction of labour (IOL) fast becoming one of the most common. In Australia, the rate of induction of labour has increased by over 30% since 2007, and today one in three women have their labours induced. We do not however have a good understanding of the contribution of specific obstetric populations to this trend.

METHODS

We examine the contribution of specific obstetric populations to induction of labour over a six-year period at one tertiary maternity service, using the Nippita classification system. Average Annual Percentage Changes (AAPC) were calculated along with 95% confidence intervals and P values set at 0.05.

RESULTS

The overall rate of induction of labour increased from 21.3% in 2012 to 30.9% in 2017, representing an Average Annual Percent Change of 8.1, P<0.0001 (95% CI 7-9.6). The greatest AAPC was seen in group 5 (parous, no previous caesarean section, 39-40 weeks, single cephalic), followed by group 2 (nulliparous, 39-40 weeks, single cephalic) and 1 (nulliparous, 37-38 weeks, single cephalic).

CONCLUSIONS

The use of the Nippita classification system allowed for standardised comparison across timepoints, facilitating identification of the subpopulations driving changes in rates of induction of labour. Rates of induction of labour saw a year on year increase which in this maternity service, it is not being driven by post-dates pregnancies. Further work is required to understand the role of other potential contributors such as diabetes.

Target populations to reduce cesarean rates after induced labor: A national population-based cohort study

INTRODUCTION

Great variations in cesarean rates after induction of labor exist and reasons for these disparities remain unclear. They may be explained by individual characteristics or obstetric practices. Ten-group classification systems have proved their utility to monitor cesarean rates in general population. We aimed to identify groups of women that account for most cesareans after induction of labor using the Nippita reproducible 10-group classification, specifically designed for induced population.

MATERIAL AND METHODS

A prospective population-based cohort study was performed in 94 French maternity units, including 3042 women undergoing induction of labor. Women were sorted according to 10 mutually exclusive groups based on parity, weeks of gestation, number of fetuses, fetal presentation and previous cesarean delivery. Relative size, cesarean delivery rate and contribution to the overall cesarean rate were described for each group. Cesarean rates were compared according to the Bishop score at the onset of labor induction. Indications for cesarean delivery were also described in the groups that contributed most to the overall cesarean rate. The MEDIP protocol was registered in ClinicalTrial (NCT02477085).

RESULTS

The overall cesarean rate was 21.0% among this population of induced women. Nulliparous women with a term singleton cephalic fetus (groups 1, 2 and 3; at 37-38, 39-40 and ≥41 weeks of gestation, respectively) accounted for two-thirds of the overall cesarean rate because they were the largest group (relative size of 10.6, 16.6 and 18.1%, respectively) and had higher cesarean rates (27.2, 30.9 and 33.0%, respectively). When the Bishop score was <6 (n = 2270/3042), cesarean delivery rates were higher (24.1 vs 10.7% if Bishop score ≥6, P < 0.01), in particular for group 1 (29.1 vs 12.5%, P = 0.02), and group 2 (33.3 vs 19.3%, P = 0.01). In groups 1, 2 and 3, which contributed most to the overall cesarean rate, a significant part of the cesareans were performed before 6 cm of cervical dilation for dystocia only (40.0, 16.7 and 17.6%, respectively).

CONCLUSIONS

Nulliparous women with a term singleton cephalic fetus and an unfavorable cervix represent the population to target for auditing induction practices. Specific actions could be implemented among this population to weigh the benefits and risks of induction and improve the management of labor induction.

High-dose compared with low-dose oxytocin for induction of labour of nulliparous women at term

BACKGROUND

The optimal oxytocin infusion regimen to induce labour with the lowest caesarean section rate, instrumental delivery rate and length of active labour is unclear. We compared the effect of a low-dose to high-dose oxytocin regimen to induce labour.

MATERIALS AND METHODS

We conducted a retrospective study of nulliparous women induced at term in a single tertiary centre from 2009 to 2015. The oxytocin induction protocol changed from a high to low-dose regimen in November 2012, affording us the opportunity to compare outcomes 3 years prior to, and following the change in protocol. Main outcome measures were caesarean section rate, instrumental delivery rate and length of active labour.

RESULTS

Four thousand eight hundred and eighty-five participants were included, 2211 were induced via the low-dose regimen, and 2674 using the high-dose regimen. There was no difference in caesarean section rate (adjusted OR 0.99; 95% CI 0.87-1.13) or instrumental delivery rates once adjusted for regional anaesthesia (adjusted OR 1.16; 95% CI 0.99-1.36) between the different regimens. Surprisingly, the length of labour was longer in the high-dose oxytocin group (adjusted mean difference 0.60 h; 95%CI 0.81-0.12). There were significantly more postpartum haemorrhage ≥1000 ml (10.5% versus 7.8%, p < .001) and regional anaesthesia use (55.8% versus 52.1%, p = .03) in the low-dose cohort. There were no differences in neonatal outcomes.

CONCLUSION

Outcomes between high- and low-dose oxytocin induction regimens are relatively comparable with similar caesarean section and instrumental delivery rates. Therefore, either regimen is acceptable for use for induction of labour.