The main decision-making body of the self-government system in Germany is the Federal Joint Committee (G-BA). In line with the principles of evidence-based medicine, randomised controlled trials with patient-relevant endpoints (in particular mortality, morbidity, quality of life) are preferred for the G-BA assessment of medical treatments and procedures. During this analysis of ultrasound screening for monochorionicity in multiple pregnancies, no studies were identified directly comparing a group with screening vs. a group without screening. Therefore, a 3-step process, which assesses the single components of screening (risk factors, relevant outcome for the patient, existence of a confirmed diagnosis, application of an effective therapy), was used. On the basis of these results the G-BA decided that the statutory health insurance should include the determination of chorionicity in their reimbursement catalogue.