Study ObjectiveMullerian duct anomalies are common in females with anorectal malformations (ARM), though there are no universally recommended screening protocols for identification. Historically, at our institution, we have recommended a screening pelvic ultrasound six months after thelarche and menarche. We aimed to evaluate outcomes associated with our post-thelarche screening pelvic ultrasounds (PUS) in females with ARM. MethodsAn IRB-approved retrospective chart review was performed of all female patients ≥ 8 years old with ARM and documented thelarche. Data was collected on demographics and clinical course. Primary outcome was adherence to recommended PUS. Secondary outcomes included imaging correlation with suspected Mullerian anatomy and need for intervention based on imaging findings. ResultsA total of 112 patients met inclusion criteria. Of these, 87 (77.7%) completed a recommended post-thelarche screening PUS. There were no differences in completion based on age, race, establishment with a primary care provider, insurance status, or type of ARM. Nine patients (10.3%) had findings on their PUS that did not correlate with their suspected Mullerian anatomy; five (5.7%) required intervention with two requiring menstrual suppression, two requiring surgical intervention, and one requiring further imaging. ConclusionMost patients completed the recommended post-thelarche screening PUS. In a small subset of patients, PUS did not correlate with suspected Mullerian anatomy and generated a need for intervention. Post-thelarche PUS can be a useful adjunct in patients with ARM to identify gynecologic abnormalities.