ASRM MAC 2021

ASRM Müllerian Anomalies Classification (MAC2021)


There are many classification systems for müllerian anomalies. Each suffers from issues that prevent its inclusivity, ease of use, understanding, and correlation to clinical diagnosis and management. The American Fertility Society (AFS) Classification from 1988 has been the most recognized and utilized, its advantages include its simplicity, recognizability, and correlation to clinical pregnancy outcomes. Criticisms have included its focus on uterine anomalies, exclusion of vaginal and cervical anomalies, lack of clear diagnostic criteria, and the lack of ability to classify complex anomalies.

The ASRM Müllerian Anomaly Classification 2021 (MAC2021) was created with several goals in mind:

  • Build on the known strengths, simplicity, and recognizability of the 1988 AFS Classification
  • Update and expand the classification to include cervical and vaginal anomalies utilizing an interactive format
  • Raise awareness of the numerous and varied müllerian anomalies
  • Standardize terminology to simplify communication and facilitate searches in scientific databases
  • Create an educational tool that includes information regarding presentation, diagnosis, and treatment
  • Apply to all levels of providers, trainees, and students across medical specialties
  • Promote patient awareness and advocacy

MAC2021 classifies müllerian anomalies into 9 categories based on similar elements in appearance, presentation, and treatment. As müllerian anomalies represent a continuum of development and many have combined elements, some anomalies may appear in more than one category:

  • Müllerian agenesis
  • Cervical agenesis
  • Unicornuate uterus
  • Uterus didelphys
  • Bicornuate uterus
  • Septate uterus
  • Longitudinal vaginal septum
  • Transverse vaginal septum
  • Complex anomalies

Important features of ASRM MAC2021

Main classification page shows representative anomalies for each category which can be expanded to show more example

Each category has 5 educational elements:

  • Variants screen shows diagrams depict the potential variations for each anomaly within the category, includes section called "also known as" with the preferred terminology identified and other synonyms listed
  • Similar to screen shows other anomalies that are similar in presentation, exam, and imaging to help providers refine their differential and arrive at the correct diagnosis
  • Presentation screen is divided into 3 sections:
    • Symptoms screen shows age at onset and typical symptoms attributed to the disorder
    • Examination screen shows key examination findings of the anomaly
    • Differential screen shows all other possible differential diagnoses for conditions with similar presentation
  • Imaging screen describes the best screening tool, diagnostic strategy, and findings for each anomaly including examples in 3 imaging modalities (not all types of imaging are present for each anomaly) 
    • MRI
    • Ultrasound
    • HSG
  • Treatment screen is divided into 3 sections:
    • Medical section describes options to suppress menstruation to treat pain
    • Dilation section describes the process for non-surgical vaginal lengthening procedures (when appropriate)
    • Surgical section describes surgical approaches to correct each anomaly, includes links to pertinent surgical videos 

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