Ultrasounds: How Many Should I Have?

By Sandra Everets

June 5, 2020

I'm a Mama of two beautiful children, Evelyn & Noah. I've worked in Obstetrics for the past 14 years. I've have the amazing pleasure of working with women and their new families through their pregnancy, labour and delivery & post partum. I look forward to getting to know your family.

Congratulations Mama you are pregnant! I know you cannot wait to see your little peanut on the ultrasound monitor and know everything is okay! Once you see the flutter of the heart there is so much relief. I remember it feeling like an eternity from the positive pregnancy test to my first ultrasound! Ultrasounds in pregnancy are safe and painless. They produce pictures of the inside of the uterus using sound waves. The sonographer uses a small probe called a transducer and gel placed directly on the skin.

DATING ULTRASOUND (7-12 weeks)
The first ultrasound you will have in your pregnancy is called a Dating Ultrasound. It does exactly that – tells us how far along you are in your pregnancy and gives your doctor an Estimated Date of Delivery (EDD/EDC) The ideal time to do this ultrasound is between 7-12 weeks so that your baby is big enough to detect and measure the heartbeat, measure the Crown Rump Length (CRL), which is measuring the baby from the head to the bum, document the number of babies, the location of the pregnancy (uterus or ectopic) and the health of your ovaries. If your dating ultrasound is done closer to 12 weeks your baby will also have a nuchal translucency (NT) measurement. The NT measures the fluid at the back of the baby’s neck. The NT measurement is part of a combined screening for chromosomal differences. Your health care provider may ask for another ultrasound between 11-12 weeks gestation to do the NT if your dating ultrasound was done earlier. When you see people announcing their pregnancies with an ultrasound picture, they are usually using a picture from their dating ultrasound. Don’t forget to ask for an ultrasound picture at the start of your ultrasound so the sonographer can capture one for you.

Anatomical Ultrasound (18-22 weeks)
Your next ultrasound will come between 18-22 weeks of pregnancy and is the most important ultrasound you will have! It is called an anatomical or anatomy ultrasound. This ultrasound will take roughly 1 hour to do (sometimes more) and you will likely need a full bladder. In this detailed ultrasound, the sonographer will be looking at your baby’s anatomy to make sure everything is developing properly. The size of your baby will be measured, how much amniotic fluid is surrounding your baby, the location of your placenta, as well as the length of your cervix will also be examined. During your anatomy ultrasound the sonographer will be looking at your baby’s brain, heart, kidneys, bladder, stomach, spine, limbs, and sex organs. You will be able to find out if you are having a boy or a girl at this ultrasound! Sometimes you must wait until your healthcare provider has been sent the ultrasound results to find out the sex while other times, they will tell you during your ultrasound.
I always tell mamas that they will often have to be called back to complete the anatomy ultrasound and this happens a lot and is normal. For the sonographer to properly examine the spine and heart your baby must be in the ideal position. And we have no control of your baby and babies can be stubborn and sometimes do not want to show us what we need to see. The sonographer may ask you to get up and walk around or have a drink in order to see if that will reposition baby but ultimately if they are unable to see everything clearly you will need to return to complete the ultrasound. Make sure you complete this ultrasound! Your anatomy ultrasound is a great time to get that picture-perfect snapshot of your baby’s profile!

If everything is normal at your anatomy ultrasound and you have a low risk pregnancy this will likely be your last ultrasound until you are at your due date/past your due date at which time they will do a BPP (read our article about BPP) Your healthcare provider, depending on your health, your baby’s health and any other medical conditions may feel you need further ultrasounds during your pregnancy. At your next prenatal appointment after the anatomy ultrasound is a good time to speak with your healthcare provider about whether they will schedule you for another ultrasound and why. For example, if you are diagnosed with Gestational Diabetes (GDM) it is recommended to have an ultrasound every 2 weeks to monitor the growth and well being of your baby.

Remember mamas there are no significant risks associated with ultrasounds, although medical guidelines caution against unnecessary exposure to ultrasounds which is why your health care provider will schedule only the necessary ultrasounds for you throughout your pregnancy.

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