Results of the DSA for the number of referrals to TVS.

Upper estimate demonstrates the impact on the difference between each pathway and the no screening pathway in terms of referrals to TVS by increasing the variable; lower estimate demonstrates the impact on the referrals to TVS by decreasing the variable. Asymmetric bars are indicative of input values already being close to the ceiling value for the input type (for example, a probability of 0.9) and therefore being unable to be increased to the full extent. Abbreviations : BL/S, bilobed or succenturiate; DSA, deterministic sensitivity analysis; IVF, in vitro fertilisation; LLP, low-lying placenta; TAS, transabdominal sonography; TVS, transvaginal sonography; VCI, velamentous cord insertion; VP, vasa praevia.