Pregnancy Ultrasounds in Ontario:
Which Scans You Get and When
Most pregnancies include a dating scan and an anatomy scan at 18 to 20 weeks, with Prenatal (NT) Screening offered in between. Here's what each scan is for, when it happens and how to prepare.
Key points
- Most pregnancies have two main Ultrasounds: an early dating scan and the anatomy scan at about 18 to 20 weeks.
- Prenatal (NT) Screening is done between 11 weeks 2 days and 13 weeks 6 days (13 weeks 3 days with eFTS), so book it as soon as you have the requisition.
- A third trimester scan is ordered only when your provider has a reason, such as checking the baby's growth.
A typical pregnancy in Ontario includes two main Ultrasounds: an early dating scan and the anatomy scan at about 18 to 20 weeks. Many people are also offered Prenatal (NT) Screening between 11 and 13 weeks. A third trimester scan is added only when your provider has a reason to order it.
Your doctor, nurse practitioner or midwife decides which scans you need and gives you a requisition for each one. Here is what each scan is for, in the order you are likely to have them.
How many Ultrasounds do you get in pregnancy?
The Society of Obstetricians and Gynaecologists of Canada recommends two Ultrasounds in every pregnancy: one to date the pregnancy and one anatomy scan. Prenatal (NT) Screening and any later scans sit around those two. On a Bluewater requisition, they appear in this order:
| Scan | When it usually happens | What it’s mainly for |
|---|---|---|
| Dating | Early pregnancy | Confirms how far along you are |
| IPS NT | 11 weeks 2 days to 13 weeks 6 days (13 weeks 3 days with eFTS) | Measures fluid at the back of the baby’s neck, part of prenatal screening |
| OB scan (anatomy) | 18 to 20 weeks | Checks how the baby’s organs and body are developing |
| Third trimester / BPP | Later in pregnancy, if ordered | Checks growth and well-being when there’s a reason to |
When is the dating scan done?
Early. Pregnancyinfo.ca notes that dating Ultrasounds are most accurate between 7 and 12 weeks. The sonographer measures the baby and that measurement gives a due date. Almost everything after it is timed from that date, including the NT scan, so book a dating scan soon after you get the requisition.
Very early scans are sometimes done with a small internal (transvaginal) probe, because the baby is tiny. The sonographer explains it first.
What is Prenatal (NT) Screening and when is it done?
NT stands for nuchal translucency, the clear fluid at the back of the baby’s neck. Prenatal Screening Ontario explains that this Ultrasound measures that fluid, can give you an accurate due date and tells you how many babies you’re expecting. Done on its own, or alongside NIPT, it can be done between 11 weeks 2 days and 13 weeks 6 days. When it is part of enhanced First Trimester Screening (eFTS), the window is shorter: 11 weeks 2 days to 13 weeks 3 days. Our requisition lists it as “IPS NT (11–13.3 wks)”.
It’s a screening test: it estimates a chance, it doesn’t give a diagnosis. Your provider will talk you through your options. The window is short, so book as soon as you have the requisition.
What happens at the 18 to 20 week anatomy scan?
This is the longer, more detailed scan most people picture. Prenatal Screening Ontario describes it as a look at how the baby’s organs and structures are developing, such as the heart, brain, kidneys, spine, arms and legs, along with the baby’s size, position and activity, the fluid around the baby, and where the placenta and cord are. It also looks at your cervix, uterus, ovaries and bladder.
A quiet sonographer is concentrating on getting each view right, not a sign of a problem. Many parents hope to learn the baby’s sex at this visit, but Prenatal Screening Ontario is clear that checking the sex is not one of the goals of this scan.
Do I need a third trimester scan?
Not everyone does. A third trimester scan, or a biophysical profile (BPP), is ordered when your provider wants more information, for example to check the baby’s growth. If your provider orders one, ask them why; they can explain what they’re looking for.
How do I prepare for a pregnancy Ultrasound?
Bluewater’s instructions for obstetrical Ultrasounds are the same for every scan:
- Drink 4 glasses (1 litre) of water, finishing 1 hour before your appointment.
- Do not go to the washroom. You need a full bladder for this exam.
- You may eat as usual.
Wear a two-piece outfit so you only need to lower your waistband a little. Bring your Ontario health card, your signed requisition and a list of your medications, and arrive 15 minutes early. The full list is on our preparation instructions page.
The sonographer can’t tell you the results. A radiologist reads the images and the report reaches your provider in 24 to 48 hours. You can also see your images through PocketHealth.
Are pregnancy Ultrasounds covered by OHIP?
Yes. With a valid Ontario health card and a requisition, diagnostic pregnancy Ultrasounds are covered in full. Without OHIP, our cash fee schedule lists these prices as of October 2026: dating $145, IPS NT $145, anatomy scan $155 and third trimester or BPP $155, with higher prices for twins or Doppler. Read Is my Ultrasound covered by OHIP? for the details.
Elective 3D/4D keepsake sessions are separate. They need no requisition, aren’t covered by OHIP and don’t replace the scans your provider orders.
Book your pregnancy Ultrasound
All ten Bluewater clinics offer pregnancy (obstetric) Ultrasound. To check which clinic does the scan you need, such as the NT scan or the anatomy scan, call 416-462-0064. Find the clinic nearest you, then book online. Learn more on our pregnancy Ultrasound page.
This article is general information. Always follow the instructions from your doctor and your appointment confirmation.
Common questions
How many Ultrasounds do you get in pregnancy?
The Society of Obstetricians and Gynaecologists of Canada recommends two: an early scan to date the pregnancy and an anatomy scan in the second trimester. Many people are also offered Prenatal (NT) Screening at 11 to 13 weeks. Your provider may order more if there is a medical reason.
When is Prenatal (NT) Screening done?
Prenatal Screening Ontario says the NT ultrasound can be done between 11 weeks 2 days and 13 weeks 6 days on its own or with NIPT, and between 11 weeks 2 days and 13 weeks 3 days when it is part of enhanced First Trimester Screening (eFTS). Bluewater's requisition lists it as IPS NT (11 to 13.3 weeks). The window is short, so book early.
What happens at the 18 to 20 week anatomy scan?
The sonographer checks how the baby's organs and body are developing, the baby's size and position, the fluid around the baby, and where the placenta and cord are. It is one of the longer appointments. Checking the baby's sex is not one of its goals.
How do I prepare for a pregnancy Ultrasound?
Drink 4 glasses (1 litre) of water, finishing 1 hour before your appointment, and do not go to the washroom before the exam. You may eat as usual. Bring your health card and your signed requisition, and arrive 15 minutes early.
Are pregnancy Ultrasounds covered by OHIP?
Yes. With a valid Ontario health card and a requisition from your doctor, nurse practitioner or midwife, they are covered in full. Elective 3D/4D keepsake sessions are separate, need no requisition and are not covered.
Keep reading
Is My Ultrasound Covered by OHIP?
What's Free and What Isn't
With a valid Ontario health card and a requisition, a medically needed ultrasound costs you nothing. Here's what OHIP pays for, what it doesn't, and what to do if you're not covered.
Do You Need a Requisition for an X-Ray or Ultrasound in Ontario?
For an OHIP-covered X-Ray or ultrasound, you need a signed requisition from a licensed provider. Here's who can write one, what to bring, and the few exams you can book on your own.