200+ Free RDMS OB/GYN Practice Questions
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Key Facts: RDMS OB/GYN Exam
170
Exam Questions
ARDMS
555
Passing Score (scaled)
ARDMS (300-700 scale)
3 hrs
Exam Duration
ARDMS
$275
Specialty Exam Fee
ARDMS
37%
2nd/3rd Trimester OB
Largest domain
10 years
Certification Validity
CME required
The RDMS OB/GYN exam has 170 questions in 3 hours with a passing scaled score of 555 (~70%). Five domains: Second/Third Trimester OB (37%), Protocols & Procedures (24%), Gynecology (19%), First Trimester OB (12%), and Physics & Instrumentation (8%). Requires SPI exam + eligible pathway. $275 specialty exam fee. 10-year certification with CME.
About the RDMS OB/GYN Exam
The RDMS OB/GYN exam validates expertise in obstetric and gynecologic sonography including first trimester evaluation, second/third trimester fetal assessment, gynecologic pelvic anatomy, scanning protocols, and ultrasound physics. It is the most popular ARDMS specialty exam.
Questions
170 scored questions
Time Limit
3 hours
Passing Score
Scaled score 555 (~70%)
Exam Fee
$275 (ARDMS (American Registry for Diagnostic Medical Sonography) / Pearson VUE)
RDMS OB/GYN Exam Content Outline
Second/Third Trimester Obstetrics
Fetal biometry, fetal anatomy, fetal anomalies, multiple gestations, placenta, amniotic fluid, biophysical profile
Gynecology - Pelvic Anatomy
Normal pelvic anatomy, uterine pathology, ovarian pathology, adnexal masses, postmenopausal findings
Protocols and Procedures
Scanning techniques, patient care, measurement standards, documentation, first trimester screening, safety
First Trimester Obstetrics
Early pregnancy, embryology, CRL measurement, NT screening, viability assessment, ectopic pregnancy
Physics and Instrumentation
Doppler principles, hemodynamics, image optimization, artifacts, transducer physics, bioeffects
How to Pass the RDMS OB/GYN Exam
What You Need to Know
- Passing score: Scaled score 555 (~70%)
- Exam length: 170 questions
- Time limit: 3 hours
- Exam fee: $275
Keys to Passing
- Complete 500+ practice questions
- Score 80%+ consistently before scheduling
- Focus on highest-weighted sections
- Use our AI tutor for tough concepts
RDMS OB/GYN Study Tips from Top Performers
Frequently Asked Questions
What is the RDMS OB/GYN exam?
RDMS OB/GYN is an ARDMS specialty exam that validates expertise in obstetric and gynecologic sonography. It covers fetal assessment, pelvic anatomy evaluation, scanning protocols, and ultrasound physics. It is the most popular RDMS specialty.
How many questions are on the RDMS OB/GYN exam?
The exam has 170 questions in 3 hours. The passing score is a scaled score of 555 (approximately 70%) on a 300-700 scale. Administered at Pearson VUE test centers.
What are the prerequisites for the RDMS OB/GYN exam?
You must pass the SPI (Sonography Principles & Instrumentation) exam first, then complete an eligible pathway: graduate of a CAAHEP/ABHES accredited sonography program or clinical experience route. Submit application and $275 fee to ARDMS.
What is the hardest part of the RDMS OB/GYN exam?
Second/Third Trimester Obstetrics (37%) is both the largest and most challenging domain. It requires mastery of fetal biometry (BPD, HC, AC, FL), fetal anomaly recognition, placental abnormalities, and amniotic fluid assessment.
How should I prepare for the RDMS OB/GYN exam?
Plan for 150-250 hours of study over 8-12 weeks. Focus on Second/Third Trimester OB (37%) and Protocols & Procedures (24%) — together 61% of the exam. Master fetal biometry measurements, anomaly detection, and scanning technique standards.