What an OB/GYN sonographer images, the exams across pregnancy and gynecology, the conditions those exams find, and the credentials and settings involved.
OB/GYN sonography covers two related areas: obstetric imaging, which follows a pregnancy, and gynecologic imaging, which examines the female reproductive organs. It is among the highest-volume areas of sonography and a very common specialty for new graduates. The work can be done through the abdomen (transabdominal) or with a probe placed internally (transvaginal), depending on what is being examined.
What it images
In gynecology, the exam covers the uterus, ovaries, the surrounding adnexa, and the cervix. In obstetrics, it covers the pregnant uterus, the fetus, the placenta, the amniotic fluid, and the umbilical cord (AIUM obstetric and female-pelvis practice parameters; ARDMS OB/GYN content outline).
The common studies
- First-trimester ultrasound. Confirms a pregnancy is viable, dates it, locates it (ruling out an ectopic pregnancy outside the uterus), and can measure nuchal translucency (AIUM first-trimester parameter, 2020).
- The standard “anatomy scan.” A second- or third-trimester survey of fetal anatomy, growth, and placental position (AIUM Standard Obstetric parameter, 2024).
- Gynecologic pelvic ultrasound. Imaging of the uterus and ovaries, often transvaginal (AIUM female-pelvis parameter).
- Fetal measurements and Doppler. Biometry, umbilical- and uterine-artery Doppler, and the biophysical profile.
The conditions it helps find
In obstetrics, the exam helps identify ectopic pregnancy, miscarriage, fetal structural anomalies, growth restriction, problems with where the placenta sits (such as placenta previa and accreta-spectrum disorders), multiple gestation, and abnormal amniotic-fluid levels (AIUM parameters, 2020–2024). In gynecology, it finds uterine fibroids, ovarian cysts and masses, abnormalities of the uterine lining, the ovarian pattern seen with PCOS, and ovarian torsion (ARDMS OB/GYN content).
The credentials
- RDMS — Registered Diagnostic Medical Sonographer, Obstetrics and Gynecology specialty, issued by the American Registry for Diagnostic Medical Sonography (ARDMS). The path requires the Sonography Principles and Instrumentation (SPI) physics exam plus the OB/GYN exam, within five years (ARDMS, 2024).
- For the fetal heart specifically, Fetal Echocardiography is a distinct ARDMS exam that can sit under either the RDMS or the RDCS (the cardiac credential), but not both (ARDMS, 2024).
- The general Sonography (S) credential from the American Registry of Radiologic Technologists (ARRT) also covers OB/GYN scope (ARRT, 2024).
Licensing and Certification covers the bodies in full.
Where the work happens
OB/GYN sonographers work in hospital obstetrics, maternal-fetal-medicine, and radiology departments; in OB/GYN physician offices and women’s-health clinics; and in outpatient imaging centers. Detailed and fetal-heart work is concentrated in maternal-fetal-medicine referral practices. Physicians’ offices account for about 21 percent of all sonography employment (BLS, May 2024).
Pay and outlook
OB/GYN work sits within the general diagnostic medical sonographers occupation (code 29-2032): a median wage of $89,340 and 13 percent projected growth from 2024 to 2034 (BLS, May 2024). No separate OB/GYN-only wage is published.
Last verified: 2026-06-14. Credential requirements change; confirm current details with ARDMS and ARRT. Salary figures are from the BLS and describe the occupation, not any individual job. This page is informational and does not recommend a specialty.