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.