Factors influencing obstetric ultrasound examination duration in a tertiary fetal center.

OBJECTIVE: To quantify scan duration across commonly performed obstetric ultrasound examinations in a tertiary fetal imaging center and to evaluate whether exam type, maternal body mass index (BMI), and sonographer experience independently influence scan time. METHODS: We conducted a retrospective cohort study of singleton pregnancies undergoing diagnostic obstetric ultrasound between January 2023 and May 2024 at a high-volume tertiary care center. Ultrasounds were categorized into five exam types: dating/viability (6-10 weeks), detailed first-trimester (11-14 weeks), detailed second-trimester anatomic survey (18-22 weeks), fetal echocardiography (22-24 weeks), and second/third-trimester growth/Doppler (24-38 weeks) scans. Scan duration was defined using ultrasound image timestamps from the first to the last acquired image. Linear regression models with log-transformed duration were constructed, adjusting for ultrasound type, maternal BMI (per 10-unit increase), prior abdominal surgery, and sonographer experience (0-4, 5-9, ≥10 years). Adjusted durations were estimated using marginal standardization. RESULTS: A total of 870 ultrasounds were analyzed. Median scan duration varied significantly by exam type: dating (6.8 min), detailed first-trimester (18.3 min), second-trimester anatomy survey (29.9 min), fetal echocardiography (26.6 min), and second/third-trimester growth/Doppler (12.5 min) scans. After adjustment, all exam types required significantly longer scan times than dating ultrasounds, with the largest increases observed for second-trimester anatomic surveys and fetal echocardiography (p < 0.001). Greater sonographer experience was independently associated with shorter scan duration, with efficiency gains plateauing after approximately 5 years. Maternal BMI was also a significant predictor of scan duration, with each 10-unit increase in BMI associated with an approximately 3% increase in adjusted scan time (p = 0.037). CONCLUSION: Scan duration in obstetric ultrasound is strongly influenced by exam type, sonographer experience, and maternal BMI. These findings provide clinically relevant information that can be used for the creation of benchmarks, scheduling templates, staffing strategies, and workflow optimization in maternal-fetal medicine ultrasound units.