Third trimester ultrasound
third trimester scan · 32-week scan · growth scan · late pregnancy ultrasound
The doctor checks the baby with ultrasound late in pregnancy: growth, position, amount of fluid, and the placenta.
Usually at 30 to 34 weeks, as part of routine care. Sometimes more often, if your doctor orders it.
⏱ Duration: usually 20 to 40 minutes; results right away
Be sure to tell your doctor
How to prepare
- Prep. Usually none. You can eat, and you do not need a full bladder.
- Clothing. Comfortable clothes, so your belly is easy to uncover.
What to bring
- Your pregnancy record (prenatal card)
- Your referral
- Past ultrasound reports
How it goes
- You lie on your back or slightly on your side
- Gel is put on your belly
- The doctor measures the baby's head, belly, and legs
- The doctor checks the baby's position, the placenta, and the fluid
- A Doppler is often done at the same time to check blood flow
What you'll feel
- Cool gel and pressure from the probe on your belly
- Lying on your back can make you dizzy. Say so, and you will be turned on your side
Afterwards
- The report is usually ready right away
- Go over the results with your own doctor at your visit
- The baby's weight on ultrasound is an estimate. It can be off
Contact a doctor straight away if
- The baby moves much less: see a doctor right away
- Bleeding, severe belly pain, or your water breaking: call emergency services
Common questions
Does the ultrasound show the baby's weight exactly?
Roughly. It can be off in either direction, so the doctor looks at more than just weight.
What if the baby is head up?
The baby may still turn before birth. Your doctor will tell you what to do next.