How to prepare for a sonography — fasting, bladder, what to wear
Different sonography types have different prep rules. Here's a quick guide to fasting, full or empty bladder, and what to bring for each common ultrasound.
The single most common reason a scan gets rescheduled is wrong preparation. Either someone ate before an abdominal scan, or showed up with an empty bladder for a pelvic scan, or wore a kurta with metal buttons. Five minutes of preparation saves a wasted trip.
Here's a no-nonsense guide to prep for the scans we do most often.
Why prep matters at all
Sound waves don't pass cleanly through everything. Gas in the intestines scatters them. A collapsed bladder hides the pelvic organs. A full stomach obscures the gallbladder. Each ultrasound type has prep rules designed to make the relevant organs visible.
Whole abdomen sonography
Goal: clear view of liver, gallbladder, pancreas, spleen, kidneys, bladder.
Prep:
- Fast for 6 hours before the scan. Only water allowed during the fast.
- Drink 4–6 glasses of water in the hour before the scan. Do not urinate until done.
- Wear loose, two-piece clothing.
Why:
- Fasting empties the stomach and intestines (less gas in the way) and fills the gallbladder (easier to see stones).
- A full bladder pushes intestines aside and lets us see the bladder wall, lower kidneys, and pelvic organs clearly.
Pelvic sonography (abdominal-wall, not vaginal)
Goal: view of uterus + ovaries (women) or prostate + bladder (men) through the lower abdomen.
Prep:
- No fasting required.
- Drink 4–6 glasses of water 1 hour before. Do not urinate.
- Wear two-piece clothing.
Why: The full bladder is non-negotiable. Without it, the uterus or prostate is hidden behind gas-filled intestines.
Trans-vaginal sonography (TVS)
Goal: detailed view of uterus and ovaries via a slim probe inserted into the vagina.
Prep:
- Empty your bladder just before the scan — opposite of pelvic ultrasound.
- Avoid scheduling during heavy menstrual bleeding.
- No fasting needed.
Why: Empty bladder lets the probe sit close to the uterus and ovaries.
Important: TVS is always done by our female sonographer with a female attendant present. You'll have full privacy.
Pregnancy scans
First trimester (up to 14 weeks):
- Drink 4 glasses of water 1 hour before for abdominal scan after 10 weeks.
- For very early scans (before 8 weeks), TVS is used — empty bladder.
- Bring last period date and any previous pregnancy reports.
Anomaly scan (18–22 weeks):
- No fasting.
- 2 glasses of water 1 hour before — not too full.
- Eat normally before. A recently-fed baby is more active and easier to image.
- Bring all antenatal reports.
- Partner welcome.
Growth scan (third trimester):
- No fasting.
- Eat normally — active baby is easier to image.
- Stay hydrated.
KUB sonography (kidneys and bladder)
Goal: detect kidney stones, evaluate bladder.
Prep:
- Drink 4 glasses of water 1 hour before. Do not urinate.
- No fasting needed.
Thyroid sonography
Prep:
- No fasting.
- Wear an open-neck shirt or kurta.
- Remove necklace before the scan.
Breast sonography
Prep:
- No fasting.
- Avoid deodorant, talc, or lotion on the chest area on the day.
- Wear two-piece clothing.
Performed by our female sonographer with a female attendant.
Doppler studies (carotid, lower limb venous)
Prep:
- No fasting.
- Wear loose clothing that allows access to the area being scanned (open-neck for carotid, shorts for lower limb).
- Carry recent ECG, lipid profile, and previous Doppler reports.
General rules across all scans
- Carry all previous related imaging. Comparing to your last scan often changes the report.
- List your medications. A few drugs can affect interpretation.
- Tell the technician about any pain you're already in. Probe pressure on a sore area is the most common cause of discomfort — we adjust technique.
- Reschedule if you're feverish. Acute illness can change findings and confuse interpretation.