Objective: To compare cost‐effectiveness of oral sildenafil citrate, administered after onset of labor, with standard care to health system funders in the UK and Australia. Methods: We conducted a modeled cost‐effectiveness analysis, measuring costs and quality adjusted life years (QALYs), using a decision‐analytic model covering onset of labor to 1 month post‐birth. The relative risk of emergency cesarean section and operative vaginal birth was taken from a Phase 2 placebo controlled double blinded randomized control trial. Results: Both options of care resulted in the same QALYs gained over the model time period (0.08). Sildenafil citrate was cost‐saving compared with standard care, saving £92 per birth in the UK (AU$303 per birth in Australia). Sensitivity analyses did not identify any areas of uncertainty that stopped sildenafil citrate being cost saving compared with standard care. Threshold analysis revealed that sildenafil citrate would be cost saving up to a per birth drug or administration cost of £152.32 in the UK (AU$333.61 in Australia). Conclusion: Oral sildenafil citrate may be cost saving compared with standard care; however, the effects on neonatal outcomes still need to be demonstrated in large randomized trials. Synopsis: Oral sildenafil‐citrate may be cost saving compared with standard care; however, the effects on neonatal outcomes still need to be demonstrated in large randomized trials. [ABSTRACT FROM AUTHOR]