ARDMS – Obstetrics and Gynecology Specialty Examination

To become a Registered Diagnostic Medical Sonographer (RDMS) with certification in the Obstetrics and Gynecology (OBGYN) specialty, candidates must have appropriate medical education and clinical experience, and pass both the Sonography Principles & Instrumentation (SPI) exam and the OBGYN specialty exam administered by the American Registry for Diagnostic Medical Sonography (ARDMS). Both exams must be successfully completed within five years of one another but can be taken in any order.

The OBGYN specialty exam is a three-hour multiple-choice test with 170 questions covering applied knowledge of obstetric and gynecologic sonographic evaluation. The exam is evaluated and assigned a numerical point value from 300 to 700; a result of 555 or above is a passing score.

Candidates must prove their eligibility to take the Obstetrics and Gynecology specialty exam by completing the ARDMS application forms and submitting qualifying documentation, including proof of formal education; verification of clinical experience; transcripts and licenses; and letters from a supervising physician, technologist, or program director. Renewing or recertifying applicants are subject to different requirements. The ARDMS provides online guides and checklists for the application process, including how to apply for, register for, schedule, and sit both the OBGYN specialty and SPI exams.

Once an application has been approved by the ARDMS, candidates must schedule their Obstetrics and Gynecology specialty exam at a local test center, and pay any exam or renewal fees. Exam results are available online immediately following the test. Candidates who do not pass the exam must wait a minimum of 72 hours to reapply and 60 days to retest.

The OBGYN specialty exam focuses on pelvic and fetal anatomy and physiology, and associated imaging techniques, with a higher percentage emphasis placed on some topics over others. The topics and test percentages are:

  • gynecology: abnormal pelvic anatomy and physiology, pediatric, reproductive, perimenopausal, and postmenopausal (24-28%)
  • gynecology: normal pelvic anatomy and physiology, pediatric, reproductive, perimenopausal, and postmenopausal (21-25%)
  • obstetrics: first trimester (11-14%)
  • obstetrics: complications (12-16%)
  • obstetrics: fetal abnormalities (10-16%)
  • obstetrics: second/third trimester normal anatomy (8-12 %)
  • obstetrics: second/third trimester assessment (4-8%)
  • obstetrics and gynecology: patient care and preparation technique (1-5%)

There are a variety of online and print resources available for preparing to take the Obstetrics and Gynecology specialty examination for the RDMS credential, including practice tests, content outlines, study guides, and sample questions based on the actual exam.


Last Updated: June 21, 2021