International Journal of Technology Assessment in Health Care


Study of progesterone for the prevention of preterm birth in twins (STOPPIT): Findings from a trial-based cost-effectiveness analysis

Oya Eddamaa1, Stavros Petroua1, Dean Regiera1, John Norriea2, Graeme MacLennana3, Fiona Mackenziea4 and Jane E. Normana5

a1 University of Oxford

a2 University of Glasgow

a3 University of Aberdeen

a4 Princess Royal Maternity Hospital

a5 University of Edinburgh


Objectives: Preterm birth contributes to a range of healthcare problems amongst infants surmounting to sizeable healthcare costs. Twin pregnancies are at particular risk of preterm birth. The objective of this study was to assess the cost-effectiveness of vaginal progesterone gel for the prevention of preterm birth in twin pregnancies.

Methods: An economic evaluation was conducted alongside a randomized placebo controlled trial (the STOPPIT trial) of vaginal progesterone gel for the prevention of preterm birth in twin pregnancies. Five hundred women were recruited from nine maternity hospitals in the United Kingdom. The outcomes of the economic evaluation were presented in terms of net benefit statistics, cost-effectiveness acceptability curves, generated using the nonparametric bootstrap method, and the expected value of perfect information.

Results: Mean health service costs between the period of randomization and discharge for mother and infant were £28,031 in the progesterone group and £25,972 in the placebo group, generating a mean nonsignificant cost difference of £2,059 (bootstrap mean cost difference £2,334; 95 percent confidence interval: −£5,023, £9,142; p = .33). The probability of progesterone being cost-effective was 20 percent at a willingness to pay threshold of £30,000 per preterm birth prevented. There is little economic justification for conducting further research into the use of vaginal progesterone gel in twin pregnancies for the prevention of preterm birth.

Conclusions: Further studies of preventive interventions for preterm birth more generally are required given the scale of the clinical and economic burden of this condition. These studies should be sufficiently powered for economic endpoints and extend beyond hospital discharge.


We thank the midwives and nurses at the hospitals, who assisted with the collection of staff resource inputs, as well as all the women who participated in the trial. We also thank members of the finance team at the hospitals who completed our research instruments.

The clinical and health economics study was funded by research grant no. CZH/4/200 from the Chief Scientist Office of the Scottish Executive. Ethical approval was obtained from the West Glasgow Ethics Committee.