Obstetric color Doppler is an ultrasound technique that uses color-coded Doppler signals to visualize and measure blood flow in the fetus, umbilical cord, placenta and maternal uterine vessels. It helps assess fetal well-being, placental function and detect issues such as growth restriction, fetal hypoxia or certain heart abnormalities. The scan is non-invasive and widely used when clinically indicated to monitor pregnancy health.

A color Doppler is commonly performed during the mid‑pregnancy anatomy scan at about 18–22 weeks to assess fetal heart and major vessels. It may be repeated later in pregnancy (typically in the third trimester) when there are concerns about fetal growth, placental function or high‑risk conditions, using umbilical, middle cerebral or ductus venosus Doppler assessments as clinically indicated.

A color Doppler ultrasound typically costs approximately: in India about ₹700–3,000 at diagnostic centers; in the UK private scans roughly £100–£400 (publicly funded when clinically needed); in the US about $200–$1,000 depending on facility. Final price varies by location, body part scanned, equipment, operator expertise and whether radiologist reporting or additional fees apply—confirm with the clinic.

A normal obstetric Doppler (usually the umbilical artery) shows a clear systolic peak with forward end‑diastolic flow. Typical benchmarks are gestation‑specific, but commonly the umbilical artery S/D ratio is <3 after 30 weeks. Resistance and pulsatility indices are low–moderate (RI ~0.5–0.7, PI ~0.5–1.5) and should be below gestational‑age 95th percentile.

If a Doppler ultrasound is positive—showing abnormal, reduced, absent or reversed blood flow or a clot—clinicians will investigate cause and severity, order confirmatory imaging, and start appropriate treatment. For suspected deep vein thrombosis this often means anticoagulation; for arterial blockage, vascular referral and possible angioplasty or surgery; in pregnancy, abnormal fetal Doppler prompts closer monitoring and sometimes early delivery.

Color Doppler ultrasound is considered safe in pregnancy when used appropriately by trained professionals. There’s no proven fetal harm from diagnostic Doppler, but it raises acoustic energy and potential thermal effects, so use should follow ALARA (as low as reasonably achievable). Clinicians avoid prolonged or unnecessary Doppler—especially in the first trimester—and perform it only when medically indicated.