Ultrasound in Pregnancy
During pregnancy, from the first trimester, we will check that your baby's development, including heart beat and the basic anatomy of the head, abdominal wall and limbs, follows on normally and as expected.
What is an ultrasound examination?
An ultrasound examination allows visualisation of your baby by the use of sound waves travelling through your skin, and reflecting back images of the structures they come across on their way.
The bone structure reflects most of the sound waves making the biggest echoes. These return a white image, when captured by the relevant software and projected on a computer screen. In these, soft tissues appear grey, and fluids, including the amniotic fluid surrounding your baby, appear black. This is because the sound waves can penetrate fluids without echoes being produced.
The sound waves involved in ultrasound examinations are too high pitched to be heard from the human ear, and therefore they are completely safe for your baby.
An ultrasound examination can help with many aspects of a pregnancy by allowing us to see and verify:
- The number of babies in your womb.
- The baby anatomy and size, which can then be related to the stage of the pregnancy.
- The baby's internal organs and whether they are developing normally.
- The placenta anatomy and whether is placed correctly between the mother and baby.
- The umbilical cord and whether it is wrapped around the baby.
- The womb, fallopian tubes and ovaries of the mother and whether any problems may arise with these during pregnancy.
Your first scan is a very exciting time, because it allows you a first glimpse of your baby. In AAFC, we can reproduce it as a printed photograph that you can take home.
What types of ultrasound are available and how are they performed?
In AAFC, a transvaginal scan will be performed by your doctor. An ultrasound probe is inserted through and across the vagina, and the images created by sound reflection are projected in a screen. This type of ultrasound is used early on in your pregnancy, during the first trimester, when an abdominal ultrasound might not be able to detect the fetus.
With a transvaginal ultrasound, your doctor will confirm a uterine location of the pregnancy (as opposed to an ectopic pregnancy) and date the stage of the development.
It is a very safe examination, performed without the use of any anesthetic. Your doctor will disinfect the transvaginal probe, cover it in a protective sheath, and lubricate it with the ultrasound gel for insertion into the vagina. By moving the probe around, the fetus will be located and observed. Your doctor will also check your reproductive organs' structures, including the developing placenta.
The scan lasts about 5 to 10 minutes and you may only experience a mild discomfort. You may return to your daily activities as normally.
You will need a minimum of three abdominal ultrasound scans during your nine months of pregnancy. One of them will be during the middle of your first trimester and follow up ultrasounds will be defined by your doctor.
During your first ultrasound, we will confirm the baby's heartbeat (7-8 weeks) and determine the number of fetuses.
An abdominal ultrasound is a very safe examination and it does not require the use of anesthetics. You will be asked to drink 3-4 glasses of water and not to go to toilet until after the scan. The doctor will then apply the lubricating ultrasound gel on your belly and by gliding a handheld probe all around your belly will be able to locate and see the fetus. The images created by the reflection of sound are transmitted and visualized in a monitor allowing the doctor to perform the examination.
The abdominal ultrasound does not last more than 10 minutes and you will not feel anything other than the cold abdominal lubricant applied at the beginning, and the mild discomfort of your bladder being full. You may return to your daily activities as normally.
3D / 4D Ultrasound
Like regular abdominal ultrasounds, the 3-dimentional (3D) and 4-dimentional (4D) ultrasounds also use sound waves to create an image of your baby in your womb. The difference is that instead of the end-result image being a 2D representation, it is a 3D model of your baby. The 4D ultrasound goes a step further creating a live video, like a movie, of your baby. With a 4D ultrasound, you may receive a movie of your baby, where you can watch your baby sleeping, smiling or yawning.
The actual 3D / 4D ultrasound examination is exactly like a conventional abdominal ultrasound, but the images are converted to a 3D or a 4D effect with the use of special software.
A 3D / 4D ultrasound allows you to see the face of your baby for the first time and they can be very popular with new parents, but, they can also be very useful in detecting a birth defect that a conventional ultrasound may miss out.