Obstetrics & Gynecology (OB/GYN) Specialty Exam Prep

The ARDMS OB/GYN specialty exam has the highest first-time pass rate among all seven specialties (80% in 2025), but its content breadth is substantial. It covers the full spectrum of obstetric and gynecologic ultrasound: normal and abnormal pregnancy, fetal anatomy survey, biometry, Doppler surveillance, and gynecologic pathology.

What the OB/GYN Exam Covers

The Obstetrics & Gynecology registration is a 170-question, 3 hours computer-based examination administered by the ARDMS. Questions are distributed across the official content domains in published weights, so a candidate who scores well in only one or two areas can still fall short overall. The most reliable way to prepare is to work through every domain in proportion to its weight rather than over-investing in the topics you already enjoy. Across all seven ARDMS specialties, repeat test-takers pass at far lower rates than first-time candidates, which makes thorough, domain-balanced preparation before your first attempt the single highest-value use of your study time.

Who This Exam Is For

The OB/GYN credential suits both sonography students sitting for their first registration and practicing sonographers adding a new specialty to an existing credential portfolio. Clinical experience in this area transfers directly to board performance, but the exam also rewards structured review of the published outline because it tests breadth that day-to-day scanning may not. Whether you are studying full time or fitting preparation around shifts, mapping each study block to a specific domain keeps your effort aligned with what the registry actually scores.

Exam Facts

Credential earned: RDMS
Exam format: 170-question, 3 hours examination
2025 first-time pass rate: 80%

High-Yield Focus Areas

First trimester evaluation and nuchal translucency measurement
Fetal anatomy survey (18–22 weeks)
Obstetric biometry and gestational age assessment
Gynecologic pathology (ovarian, uterine, adnexal)
Doppler surveillance and growth restriction

Key Topics

Normal early pregnancy and ectopic pregnancy
Nuchal translucency and first trimester screening
Fetal anatomy survey structures
Obstetric biometry (BPD, HC, AC, FL)
Placental evaluation and previa
Doppler waveforms (umbilical, MCA, uterine)
Intrauterine growth restriction
Gynecologic pathology
Adnexal masses

How to Prepare

Start by downloading the current ARDMS OB/GYN content outline from ardms.org and allocating your study time in proportion to each domain's weight. Use Ultrasound Analytics to practice with 170-question timed exams that mirror the real ARDMS format. After each session, review your domain-level performance breakdown on the analytics dashboard to identify which content areas need more work and adjust your focus accordingly.

Related Specialties & Resources

Many sonographers pursue more than one registration. These specialties are most commonly paired with OB/GYN when planning a multi-credential path:

Continue with free OB/GYN practice questions, browse the full ARDMS practice-question hub, weigh your options on the specialty comparison hub, or read study guides on the Ultrasound Analytics blog.