Every pregnant woman should undergo at least four ultrasound examinations during pregnancy:

• Before the 7th week of pregnancy — At this early stage, ultrasound is used to confirm a normal pregnancy within the uterus and to detect any abnormalities that may arise during this period.
• At 12–13 weeks of pregnancy — This ultrasound helps identify possible fetal developmental defects that can occur at this stage.
• At 20–25 weeks of pregnancy — This is the optimal time to detect up to 90% of possible fetal abnormalities. During this period, the formation of all fetal organs and systems can be monitored, as well as the baby's development in the womb.
• The final ultrasound should be done closer to delivery, at 37–38 weeks. Repeat ultrasounds pose no health risk.