Obstetrical Ultrasounds

How is the procedure performed?

The sonographer will ask you to lie on your back on an examination table and to remove any clothing from your abdominal area. He or she will then protect your clothes with a cloth and will apply a warm gel to your abdomen before pressing the transducer against your skin. This probe produces sound waves which are used to view the body’s internal organs. In some cases, an endovaginal ultrasound has to be done, wherein a special kind of ultrasound probe is inserted into the vagina. This technique reveals more detailed images of the fetus, uterus and ovaries. You will first need to empty your bladder, remove your clothing from the waist down and assume a position similar to the one used for a pelvic exam.

Ultrasound images are displayed in real-time on a monitor that the sonographer watches while moving the transducer. You can also see the images.

What will I experience?

Ultrasound examinations are painless. You could experience some discomfort from pressure as the transducer is pressed against certain areas to capture images, especially when the bladder is full. Any discomfort is minimal and temporary. The sonographer ensures that the patient is as comfortable as possible.

1st Trimester

2nd Trimester

3rd Trimester

Nuchal
Translucency

Length of Pregnancy:

Reasons for the ultrasound:

The first trimester starts when your baby is conceived and runs through week 15.

- Estimate the gestational age;

- Establish the presence of a living fetus or a living embryo;

- Look for multiple pregnancies;

- Rule out or detect an abnormal pregnancy (ectopic, extrauterine, molar, anembryonic, etc…)

The second trimester starts at week 15 and runs through week 25.

- Assess the fetal morphology: usually done between 18 and 20 weeks gestation. The sonographer evaluates each part of the fetus, placenta and uterus according to the standards established by the Society of Obstetricians and Gynaecologists of Canada (SOGC). It is also during this ultrasound that parents can find out the sex of their baby, if they want;

- Establish the presence of a living fetus;

- Estimate the gestational age;

- Detect abnormalities or track their progress;

- Look for multiple pregnancies.

The third trimester begins at 26 weeks and ends with delivery (around 40 weeks).

- Establish the presence of a living fetus;

- Determine the fetal biophysical profile;

- Assess fetal growth;

- Determine fetal orientation;

- Detect abnormalities or track their progress;

- Evaluate the position of the placenta;

- Measure the quantity of amniotic fluid.

The nuchal translucency ultrasound must be performed between 11 weeks + 4 days and 13 weeks + 6 days of pregnancy.

- Measure the nuchal translucency.

Prep:

Your bladder should be full, enough to experience discomfort. You must finish drinking 1 litre of water one hour before your appointment time. Do not urinate until after your exam is completed.

No preparation is required.