Aim: Migraine is the second most disabling condition worldwide. Monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) pathway represent an effective prophylactic treatment; however, their impact on cerebral hemodynamics remains unclear. The aim of this pilot study was to evaluate cerebrovas- cular risk in patients with migraine without aura treated with these therapies, by calculating the breath-holding index (BHI) of the anterior cerebral circulation using transcranial color-coded Doppler (TCCD) ultrasonography. Material and methods: Cerebral vasomotor reactivity to hypercapnia was assessed using the breath-holding test combined with TCCD ultrasonography in 40 patients with migraine without aura undergoing treatment with anti-CGRP monoclonal antibodies and 40 healthy subjects. BHI values and other key cerebrovascular parameters were compared between the groups. Results: The BHI values in patients with migraine without aura were not below the threshold predictive of increased cerebrovascular risk (less than 0.69% per second, as referenced in the general population). No significant differences were observed in major cerebrovascular parameters between cases and controls. Additionally, a subanalysis revealed no significant differences based on the specific monoclonal antibody (erenumab, fremanezumab, or galcanezumab) or clinical response status (responders versus non-responders). Conclusions: Our findings suggest that treatment with anti-CGRP monoclonal antibodies is not associated with a BHI indicative of increased cerebrovascular risk. Notably, this is the first study to include galcanezumab and fremanezumab in the evaluation of cerebrovascular risk using ultrasound, highlighting TCCD ultrasonography as a practical and non-invasive tool for the assessment of cerebrovascular reactivity in migraine.