The Different Types of Pregnancy Scan Unveiled

You are pregnant for the first time and now you are a little concerned because your gynecologist has advised you to go through a sonography or an ultrasound. Well, there’s no need to panic as an ultrasound has become a regular feature of prenatal medical care for most pregnant women. 

Although ultrasounds are not necessary for every expectant mother, they help in determining the approximate date of delivery and reveal the health of a fetus. A standard ultrasound will provide your gynecologist with important information regarding the fetus so that the baby’s growth and milestones can be tracked. The ultrasound will also show if there is more than one fetus present in the uterus and the position of your placenta. 

Besides the medical benefits of an ultrasound, it will also give you the first glimpse of the little life growing inside of you.

Pregnancy scans are generally noninvasive, painless procedures carried out on pregnant women which are used to determine various factors associated with the fetus such as the health, size, sex any abnormality and the expected date of delivery. 

During an ultrasound examination, a plastic transducer is moved over the abdominal area to transmit high-frequency sound waves through the uterus. A black and white image of your baby is then produced on a screen from the sound waves that bounce off the fetus. The image produced is generally quite grainy so feel free to ask the technician as many questions about the image as you like. 

There are different types of scans carried out at various stages of pregnancy which are used to determine the health of the fetus and several other factors associated with it. However, there is no need to go through every single procedure on the list as your doctor will only prescribe the ultrasound that is absolutely necessary for you. 

These scans are conducted at the very early stages of pregnancy at 6 to 8 weeks on expectant mothers who may have gone through a previous miscarriage or an ectopic pregnancy where the fetus has grown outside the womb. A transvaginal scan is slightly invasive but painless. 

To check on the growth, size and age of your baby, and to monitor the heartbeat, your doctor will insert a thin probe coated with lubricating gel, into your vagina. This transducer transmits sound waves of high-frequency into your uterus and a black and white image of your baby is then produced on a screen from the sound waves that bounce off the fetus. Since the baby is too tiny at this stage, there won’t be much to gush about from this image.

This scan is offered to all expectant mothers between 11 to 13 weeks of pregnancy. The NT ultrasound helps doctors determine if you risk having a baby with Down syndrome, certain heart defects or trisomy 18, which is another chromosomal disorder. 

The test is carried out in two parts – a blood test to measure the levels of certain proteins and hormones, and a scan to gauge the thickness of the baby’s neck. An increased thickness is usually an indication that the baby may be at risk from any of the chromosomal abnormalities. 

Source: Ben Smith / Wikimedia Commons

The standard ultrasound is a common procedure which almost all women go through to check on the health of the fetus developing inside of them. This is usually carried out in the second trimester generally between 18 to 20 weeks of pregnancy. Pregnant mothers are usually advised to drink lots of water before the test as a full bladder helps make the results of the test clearer. However, it is always better to consult your doctor about any preparatory measures that you need to take before the test.

During the test, the technician applies some special gel over the abdominal region and uses a probe to produce black and white images on a screen. The probe is moved around several times and images of the developing fetus is projected. Feel free to ask the technician to explain the images to you so you get a better idea of what you’re looking at on the screen. A printout of the image will also be given to you to add to the ‘baby book.’

Also called a level II ultrasound, this procedure is not very different from the standard ultrasound and also takes place between 18 to 20 weeks of pregnancy. The biggest difference in this kind of ultrasound is that the doctor will usually target specific areas to get more detailed information about your baby’s organs. 

During this ultrasound, the doctor will be able to detect any birth defects such as Down syndrome and point out the sex of the baby. The same method of applying gel over the abdomen and moving a probe around to produce images on a screen is used for this scan. The doctor will usually give you the report right away or within 24 hours. 

This kind of ultrasound is usually carried out on expectant mothers suffering from gestational diabetes or hypertension. Unlike the regular ultrasound where images are produced from sound waves, a Doppler ultrasound bounces high-frequency sound waves from red blood cells to estimate your blood flow through blood vessels. 

This will not only help doctors in determining the state of your health but will also help them gauge if your baby is receiving enough blood. The test is carried out by a trained technician who will press a transducer as big as the size of a bar of soap against the area of your body that is being examined.

These ultrasounds are not usually prescribed by doctors as the only benefit from them is that you get to see as close a picture of what your baby looks like. Like the name suggests, the 3D ultrasound will create a three-dimensional picture of your baby while the 4D ultrasound will allow you to witness small movements like a smile or a yawn on your baby’s face. 

3D and 4D ultrasounds use the same technology as the standard ultrasounds where sound waves create an image on a screen. However, the machinery used is more advanced as the images produced are more realistic. These ultrasounds although not generally prescribed, will enable doctors to detect certain defects like a cleft palate, which may not show up in a regular scan. 

Not all expectant mothers are advised to undergo this scan as the regular ultrasounds are sufficient enough for doctors to determine whether the fetal heart has developed all four chambers. However, if there is a history of congenital heart disease in the family or if previous scans showed some abnormality then a fetal echocardiography is advised. 

This procedure which is usually carried out in the second trimester between 18-24 weeks is like the regular ultrasounds where a transducer probe is moved around the mother’s abdomen to visualize the fetal heart. The test helps doctors detect any abnormalities in the fetal heart before birth so that the baby can receive swift treatment after delivery. 

There is no specified number of scans that an expectant mother needs to undertake. The number differs from person to person and also depends on your healthcare provider. Women with complications during pregnancy or those with more than one fetus are generally advised 2-3 ultrasounds but most healthy women undergo one ultrasound during the second trimester between 18 to 20 weeks of pregnancy to confirm normal anatomy and the due date. The American College of Obstetricians and Gynecologists (AOG) recommends only one to scans during pregnancy.

Ultrasounds on pregnant women are carried out on a regular basis as they are generally a non-invasive procedure with no known risks to the fetus. However, it is very important to get the test done at a proper medical center to get the right diagnosis from a trained professional.

Doctors also advise against getting a ‘keepsake’ ultrasound (3D and 4D ultrasound) at a local mall or office building as the people conducting the tests may not be trained professionals. Experts also caution that too many ultrasounds may not be good for your baby.  

A new report by The Wall Street Journal says that the number of scans recommended by doctors has increased alarmingly over the past few years. This is probably due to the fact that more doctors are afraid of being sued so they conduct regular checks to make sure the baby is okay. The long term side effects of multiple scans on a developing fetus are still unknown, so if there are no complications with your little one, the best thing is to avoid unnecessary scans. 

As per ACOG’s recommendations get a scan done at 10 to 12 weeks and another at 18 weeks, but if your doctor recommends more than the prescribed number make sure to ask questions. Medical guidelines clearly state that there is no need for an ultrasound to be carried out unless there is a valid medical reason for it. And yes, you can do without the 3D ‘keepsake.’