Most pregnant women only need to have ultrasound twice: once in the first trimester (6 to 8 weeks) and another in the 2nd trimester (18 to 20 weeks)⁴. The doctor may also order a scan in the third trimester (30 weeks) to check for growth, placental placement, fetal position, or anything that may block the cervix⁵.
Additionally, the doctor may decide you need more scans should some issues arise. Fetal biometry, in particular, is necessary if:
- Your abdomen is smaller or larger than expected
- You have conditions, such as hypertension or diabetes
- You had previous pregnancy complications before
What To Expect Before, During, and After an Ultrasound Scan
Before the scan, you might have to drink plenty of water as a full bladder helps with the imaging.
During the procedure, the sonographer will ask you to lift your shirt and apply gel to your abdomen. They will then use a wand-like scanner around your abdomen, and you’ll be able to see the image instantly on the monitor.
After, you’ll be given wipes to remove the gel, and the results, including fetal biometry, will be sent to the doctor for interpretation.