Purpose: To estimate the cost-effectiveness of screening for vasa previa at 18-20 weeks gestation in Ontario. Universal and targeted screening strategies were considered in singleton and twin pregnancies.
Methods: We constructed a decision-analytic model to estimate the incremental costs and benefits of screening for vasa previa at 18-20 weeks gestation. We compared the status quo of no routine screening to scenarios with targeted and universal screening. Costs were collected from London Health Sciences Centre, from the Ontario Health Insurance Program Schedule of Benefits for Physicians, and other sources. Health benefits were measured in life-years gained and quality adjusted life-years gained. Lifetime discounted costs and health benefits were estimated for a cohort of pregnancies in Ontario in 1 year.
Results: Universal transvaginal ultrasound screening of twin pregnancies has an incremental cost effectiveness ratio of $4,200 per QALY-gained. Screening all singleton pregnancies with low lying placentas, IVF conception, accessory placental lobes, or a velamentous cord insertion has an incremental cost of $8,700 per QALY-gained even though identifying some of these risk factors requires routine use of color Doppler during transabdominal exams. Adding marginal cord insertion to this list of risk factors costs an additional $19,200 per QALY-gained. Universal transvaginal screening of singleton pregnancies for the purposes of diagnosing vasa previa costs $587,000 per QALY compared to targeted screening. Overall, results were robust in sensitivity analysis. However, if transvaginal ultrasound has specificity for vasa previa diagnosis lower than 99%, including marginal cord insertion as an indication for transvaginal screening has a ICER greater than $200,000 per QALY; screening all singleton pregnancies with any of the more highly predictive risk factors cost less than $50,000 per QALY as long as the specificity of transvaginal ultrasound is greater than 95%.
Conclusions: Screening all twin and all high-risk singleton pregnancies for vasa previa have very low incremental cost effectiveness ratios compared to funded screening programs and should be considered for implementation in Ontario and comparable jurisdictions.
Candidate for the Lee B. Lusted Student Prize Competition