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Pregnant: What To Expect At Your 12-Week Ultrasound

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For expectant parents, every ultrasound is a momentous occasion. Getting to see your baby for the first time is something you’ll never forget. You may experience a range of different feelings, from joy to anxiety.

You might also experience confusion. Reading a grainy ultrasound image can be difficult for an untrained eye. But don’t worry; your doctor will walk you through every scan and what they mean.

Don’t feel shy to ask follow-up questions. You want to know that your baby is developing perfectly or what’s going on inside your uterus.

You also want to be able to take your ultrasound photograph (sonogram) home so you can show the pictures to your friends and family. So we’ve put together a guide explaining what to expect at your 12-week scan, and questions you should ask.

  1. Why 12 Weeks?
  2. What to expect and how to prepare for your 12-week scan?
  3. Questions around the due date
  4. Questions about genetic disorders
  5. Questions about multiple birthdays
  6. What physical traits can you detect from the 12-week scan?
  7. How to read an ultrasound or sonogram?
  8. Can I find out about the sex at the 12-week scan?
  9. What if the scan detects a cyst?

1. Why 12 Weeks?

Ultrasounds are performed to monitor a baby’s development. Around 12 weeks, your doctor will want to make sure that you’re getting proper care, and that you and your baby are healthy. The first ultrasound is usually at the end of your first trimester. 

You may have heard people getting scans before 12 weeks, but these cases tend to be high risk. Generally, two ultrasounds are recommended throughout the duration of a pregnancy.

2. What to expect and how to prepare for your 12-week scan?

Being prepared for your scan will allow you to relax and enjoy it more because you’ll know what to expect. 

To begin, you’ll need to get some blood work done. Bloods are usually taken prior to the appointment. 

About an hour before your appointment, drink 500-750ml water, so you have a full bladder. Having a full bladder produces a clearer image. Your doctor will do an external scan. If they can’t capture a clear image, they may opt for an internal scan. Both scans are completely safe for you and your baby. 

For the external scan, you’ll lie on an examination table, and the sonographer will apply gel to your stomach. They will then use the ultrasound wand to scan your baby. You might experience a bit of discomfort because of having a full bladder, and the gel is a little bit cold but other than this, it should be completely painless. 

A 12-week ultrasound will detect:

  • The estimated due date
  • The probability of chromosomal or genetic disorders
  • Whether there are multiple babies

Aside from learning important information about your baby, one of the really exciting moments is hearing your baby’s heartbeat. 

Ultrasounds usually take between half an hour and forty-five minutes. Use this time to engage with your doctor and to ask questions. 

3. Questions around the due date

Unless you were actively monitoring your cycle, many new moms can’t pinpoint the time they conceived and ovulation isn’t always an exact science.

Don’t stress if you can’t remember the exact dates of your last menstrual cycle. The ultrasound is perfect for monitoring whether your baby is growing at a healthy rate and determining their due date.

4. Questions about genetic disorders

At 12 weeks, your doctor will do what’s called nuchal translucency screening. This is when your doctor perform an ultrasound to analyse your baby’s neck fluid. 

The results will indicate the probability of chromosomal disorders such as Down syndrome, Patau syndrome, and Edwards syndrome. It’s important to realise that these tests aren’t definitive and are used to screen for probability rather than high accuracy. 

5. Questions about multiple birthdays

The likelihood of having a multiple birth is about 3 in 100, but the rate is increasing. This is due to IVF and fertility treatment, but also because women are having children later in life. Women over thirty are more likely to conceive twins. 

At the 12-week scan you’ll find out whether you’re carrying multiples. It is also possible to tell whether you are carrying monochorionic twins (always identical). 

Monochorionic twins need to be monitored closely because they can share both a placenta and amniotic sac. Dichorionic twins make up roughly one-third of identical twins and they have separate placentas. They need less monitoring because there is less chance of complications. 

6. What physical traits can you detect from the 12-week scan?

The 12-week ultrasound is often the first time you get to see your baby and listen to its heart beat. This bonding experience allows you to check up on the health of your baby and see how the foetus is forming. 

Not all of these physical features will be visible on the ultrasound, but at 12-weeks here’s how your baby is developing:

  • The length of your baby is about 6-6.5cm 
  • Your baby has the features of a human, and all of its body parts on in place
  • Your baby’s skin is translucent
  • Bones are hardening, and fingernails are forming

From the ultrasound you’ll be able to see baby’s head and limbs. You’ll also be able to detect movement and sometimes even hiccoughing. 

Nuchal Translucency scan
Image 1: Nuchal Translucency
Nasal Bone Scan
Image 2: Nasal Bone
Twin Membrane and Two Placenta ultrasound
Image 3: Twin Membrane and Two Placenta

7. How to read an ultrasound or sonogram?

Ultrasound or sonography is an imaging test that uses sound waves. This makes it a non-invasive and safe diagnostic tool that can diagnose many conditions or provide image guidance during a range of procedures. 

Most people are familiar with the external ultrasound exam that is used during pregnancy. However, there are also internal ultrasound exams used to examine female reproductive organs, where a small device is placed inside the body. 

At your ultrasound exam, what you see on the screen is from reflected sound waves that form an image of organs and tissues. When you get your printout, here’s what to look out for:

  1. Text: You’ll notice text at the top of the image that might include your name, the hospital reference number, and some of the details about the machine settings. It will also indicate when your last menstrual period was. 
  2. Colour: Most commonly images are black and white. On the actual ultrasound, there may be different colours present that represent the direction and speed of blood flow. If the image is dark, it means tissue is filled with fluid. Gray means tissue, and white indicates bone.
  3. Clarity: Unfortunately, it isn’t easy to get very clear ultrasound images because sound waves don’t bounce evenly. This is why your medical practitioner will adjust the settings to get the best clarity. By adjusting settings, a doctor may be able to pick up things such as excess fluid, and whether there is a cyst present. 

8. Can I find out about the sex at the 12-week scan?

If you’re a parent who wants to know about the sex of your baby, then you’ll have to exercise a bit more patience. A baby’s sex can only be determined between 18 and 20 weeks.

There are three lines that medical practitioners look for that signify a penis or labia. 

To detect whether it’s a girl, you look for the hamburger sign and the sagittal sign. A girl’s labia looks like a hamburger bun. If you look at the foetus in profile, you’ll be able to detect whether there’s a nub at the end of the spine (caudal notch) pointing downwards at a 10-degree angle. 

To detect whether it’s a boy you’ll often be able to see male genitalia. The caudal notch will point upwards at more than a 30-degree angle. 

9. What if the scan detects a cyst?

During an ultrasound, your doctor may find an ovarian cyst. These cysts are fluid-filled sacs that develop in the ovaries. They are common, and most are benign, which means they won’t cause any harm unless they are large and causing pain. 

Functional and Pathological ovarian cysts are the two most common types of ovarian cysts in pregnant women. Functional cysts develop as part of the menstrual cycle and are nothing to worry about. Pathological cysts occur because of abnormal cell growth. They are very rare. It’s even rarer for them to become malignant (cancerous). 

If you have an ovarian cyst during pregnancy, it shouldn’t affect your pregnancy or the baby. Most functional cysts disappear over the course of a pregnancy. However, if a large or complex cyst is identified, then you will be monitored with extra scans and perhaps even blood tests. 

Cysts may impact on how you conceive in the future, and if you have a cyst that continues to grow throughout pregnancy, then your doctor may recommend surgery. If a doctor recommends having an operation, it will generally only be performed in the second trimester unless it is determined as critical. 

Book your 12-week appointment

The first-trimester scan is an exciting time, but it can also be a nervous time, especially if you don’t know what to expect. 

The 12-week ultrasound allows you to learn some key details about your baby and how to manage your pregnancy. Having more knowledge allows you to be more relaxed and at ease, which will help you enjoy your pregnancy journey. 

It’s important that an ultrasound is conducted by a professional, and you should be guided by their advice. Most importantly, don’t avoid asking questions because you’re shy or afraid of sounding silly – make the most of every moment. 

Find out more about the process and book your appointment for your first ultrasound with ERAD here.

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