Should Bedside Ultrasound Be Done Every Visit for Pregnancy?
No, bedside ultrasound should not be performed at every prenatal visit for low-risk pregnancies, as there is no convincing evidence that routine antenatal testing improves perinatal outcomes, and false-positive results may lead to unnecessary interventions that increase the risk for Cesarean delivery or complications related to premature delivery. 1
Evidence Against Routine Ultrasound at Every Visit
The American College of Radiology explicitly states that routine antenatal fetal surveillance by any imaging modality is not recommended in pregnancies at low risk for intrauterine fetal demise. 1 This recommendation is based on:
No demonstrated benefit: A review of five trials involving 14,185 women concluded that umbilical artery Doppler ultrasound in low-risk or unselected populations had no maternal or perinatal benefits. 1
Potential for harm: False-positive results in low-risk pregnancies may lead to unnecessary interventions, including increased Cesarean delivery rates and complications related to premature delivery. 1
Lack of improved outcomes: There is no convincing evidence that routine antenatal testing in low-risk pregnancies improves perinatal outcome, regardless of the imaging modality used (biophysical profile, modified biophysical profile, Doppler velocimetry, or functional fetal echocardiography). 1
Recommended Ultrasound Schedule for Low-Risk Pregnancy
Instead of ultrasound at every visit, the evidence supports a more targeted approach:
One routine ultrasound: The National Institute of Child Health and Human Development multi-specialty panel recommends that at least one ultrasound be offered routinely to all pregnant women between 18 and 20 weeks of gestation. 1
Standard anatomic survey: This single comprehensive ultrasound at 18-20 weeks allows for thorough evaluation of fetal anatomy and has been agreed upon by multiple organizations (ACR-ACOG-AIUM-SMFM-SRU). 1
No routine third-trimester screening: Multiple international guidelines (United Kingdom, New Zealand, Canada, Ireland, United States) do not recommend screening with routine third-trimester ultrasound in low-risk women. 1
When Additional Ultrasounds Are Indicated
Additional ultrasounds beyond the standard 18-20 week scan should be reserved for specific clinical indications:
Fundal height discrepancies: Serial fundal height measurement at every visit should prompt ultrasound if measurements are <10th centile, show slow or static growth, or have >3 cm discrepancy with gestational age. 1
High-risk conditions: Pregnancies complicated by hypertensive disorders, diabetes, chronic renal disease, intrauterine growth restriction, decreased fetal movement, multiple gestations, or amniotic fluid abnormalities warrant serial ultrasound surveillance. 2, 3
Late presentation: A routine diagnostic ultrasound may be used in the third trimester for patients with late arrival for prenatal care. 1
Common Pitfalls to Avoid
Over-testing low-risk patients: Routine testing in low-risk pregnancies causes iatrogenic prematurity from false-positive results without improving outcomes. 2, 3
Ignoring clinical indicators: While routine ultrasound at every visit is not indicated, clinicians should maintain vigilance for clinical signs (abnormal fundal height, decreased fetal movement, maternal symptoms) that warrant targeted ultrasound evaluation. 1
Confusing point-of-care capability with indication: Although point-of-care ultrasound technology is increasingly available and can be valuable for specific maternal assessments (cardiopulmonary status, emergency situations), this does not justify routine fetal surveillance at every visit in low-risk pregnancies. 4, 5, 6
Risk Stratification Approach
The key is distinguishing between low-risk and high-risk pregnancies:
Low-risk pregnancies: One comprehensive ultrasound at 18-20 weeks, with additional imaging only for specific clinical indications. 1
High-risk pregnancies: Serial ultrasound surveillance initiated at 32-34 weeks (or earlier depending on the condition), typically every 2-4 weeks, with additional Doppler studies if growth restriction is suspected. 2, 3
This evidence-based approach maximizes benefit while minimizing unnecessary interventions and healthcare costs. 1, 3