A color Doppler ultrasound is commonly performed in the second trimester—around 18–22 weeks (approximately the 4th–5th month) as part of the anomaly scan to evaluate fetal heart and blood flow. It may be repeated later in pregnancy (typically in the 7th–9th months) if there are concerns about fetal growth, placental function, or blood‑flow abnormalities.

Doppler ultrasound in pregnancy evaluates blood flow in the placenta, umbilical cord and fetal vessels to assess fetal well‑being and oxygen delivery. It helps detect placental insufficiency and fetal growth restriction, monitor pregnancies complicated by preeclampsia, twin issues or other high‑risk conditions, guide timing of intervention or delivery, and reduce risk of adverse outcomes by informing clinical management.

Yes. Color Doppler ultrasound is considered safe in pregnancy when performed by trained professionals for appropriate medical reasons. It uses sound waves to evaluate blood flow and has no proven harmful effects on mother or fetus. Exposures should follow the ALARA principle—limited to what is clinically necessary and as short as possible—so providers recommend it only when benefits outweigh any theoretical risks.

Colour Doppler ultrasound detects and visualizes blood flow in vessels and organs, showing flow direction and relative speed. It helps identify narrowed or blocked arteries, blood clots, aneurysms, varicose veins, and abnormal vascular supply to organs or tumours. It evaluates cardiac valve function and congenital heart defects, assesses placental and fetal circulation, and guides vascular procedures and treatment planning.

The last routine scan in pregnancy is the third‑trimester (growth or late) scan, usually done around 32–36 weeks — often about 36 weeks — to check fetal growth, presentation (head or breech), placenta and amniotic fluid. Additional scans may be scheduled later if concerns arise, such as reduced fetal movements, suspected growth restriction or other complications.

Color Doppler ultrasound is used to visualize blood flow and cardiac structures, not to determine fetal sex. Fetal gender is identified by direct visualization of genitalia on standard (2D) ultrasound—usually reliable after about 16–20 weeks—or by genetic tests like cell‑free DNA. Color Doppler may assist anatomical views but is not a primary or reliable method for sex determination.