Is it Cost-Effective to Induce Labour Early to Prevent Shoulder Dystocia? Evidence from the Big Baby Trial

Shoulder dystocia is associated with maternal complications, such as maternal hemorrhage or perineal tears, and neonatal complications, including fracture of the clavicle or humerus, brachial plexus injury, hypoxic ischemic encephalopathy, or death. Macrosomia infants and those who are large for gestational age (LGA) are at increased risk of shoulder dystocia. Early induction of labor (IOL) may mitigate the risk of shoulder dystocia by reducing neonatal weight at delivery. However, the clinical effectiveness of early IOL in preventing shoulder dystocia and reducing complications remains unclear. The Big Baby trial, which compared early IOL and standard of care in 2893 women with LGA fetuses, found a statistically nonsignificant reduction of shoulder dystocia in the intention-to-treat analysis but a significant reduction in the per-protocol analysis. The trial also found that those who underwent early IOL had fewer operative deliveries and postpartum hemorrhage, but longer hospital stays. Few studies have reviewed the costs associated with strategies to reduce shoulder dystocia. The aim of this study was to examine the cost-effectiveness of early IOL versus standard care to prevent shoulder dystocia in suspected LGA fetuses. This was an economic evaluation conducted within the Big Baby trial, a prospective multicenter randomized controlled trial of pregnant women in the UK between June 2018 and November 2022. The within-trial evaluation focused on a cost-effectiveness assessment, expressed as the incremental cost per case of preventing one case of should dystocia, and a cost-utility analysis, expressed as the cost per maternal quality-adjusted life year (QALY) gained. Of note, the study reported costs in British Pound, which are worth about $1.35. The early IOL arm had significantly lower antenatal costs [mean difference (MD) = £-40, 95% CI, −£56 to −£24; P < 0.01] as well as postnatal maternal costs at 2 months (MD = £-10, 95% CI, −£83 to £63, P = 0.79) and at 6 months (MD = £-7, 95% CI, −£35 to £21; P = 0.62). However, the early IOL arm had significantly higher total infant costs (MD = £330, 95% CI: £42 to £620, P = 0.02). The adjusted total combined cost difference showed a higher cost for IOL (£326), but was not quite statistically significant (95% CI: −£23.07 to £675.63, P = 0.06). For women, the early IOL arm had a non-significant increase in QALYs (MD = 0.001, 95% CI, −0.005 to 0.008, P = 0.69). The incremental cost per case to prevent shoulder dystocia was £11,879, with the probability of early IOL being cost-effective ranged from 32% at the £5000 cost-effectiveness threshold to 65% at the $20,000 threshold. There was an incremental cost per maternal QALY gained of £39,518, with a 36% probability of cost effectiveness at the $20,000 threshold. In conclusion, while early IOL reduced the incidence of shoulder dystocia, it was also associated with higher costs. (Abstracted from BJOG: An International Journal of Obstetrics & Gynaecology, 2025; 132:1250–1258)