Obstetric ultrasound uses sound waves to produce pictures of a baby (embryo or fetus) within a pregnant woman, as well as the mother's uterus and ovaries. It does not use ionizing radiation, has no known harmful effects, and is the preferred method for monitoring pregnant women and their unborn babies.
Commonly followed protocol for sonographies in pregnancy are:
- Confirmation & Dating Scan : Generally done at 6-9 weeks of pregnancy.
- NT Scan/Level 1 Scan: Done between 11-13 +6 weeks of pregnancy.
- Anomaly / Level 2 Scan: Done between 18-20 weeks of pregnancy, to look for fetal structural abnormalities.
- Fetal Echo Cardiography : Dedicated evaluation of fetal heart. Done between 24-26 weeks of pregnancy.
- 3rd Trimester Scan with Color Doppler: Done between 32-36 weeks of pregnancy for fetal growth evaluation.