Pregnancy Ultrasound Scans in 1st, 2nd & 3rd Trimester

Ultrasound Scans During Pregnancy – Types, How to Prepare and More

Medically Reviewed By
Dr. Sabiha Anjum (Gynecologist/Obstetrician)
View more Gynecologist/Obstetrician Our Panel of Experts

An ultrasound scan sends high-frequency sound waves to the uterus during pregnancy to capture the image of the foetus. Images in ultrasound scans reveal the developmental phases of the body, often revealing bones and tissues through shades of white and grey.

What is an Ultrasound Scan?

An ultrasound scan is used to get a sneak peek of your baby and analyse how the foetus is faring inside the womb. It’s primarily used to detect signs of abnormalities and monitor the growth of the foetus. However, the gender of the baby is not revealed through an ultrasound scan in India, as it is considered illegal. Nowadays, 4D and 3D colour scans are popular ultrasound choices during pregnancy for revealing high-quality images of babies.

Are There Any Risks or Side-Effects of Ultrasounds During Pregnancy?

For over 40 years, ultrasound scans have been used during pregnancies with no known side-effects. It is safe, and forms an essential part of ensuring your baby is developing well in the womb.

When and Why You Need a Sonography in Pregnancy

You need a sonography (ultrasound scan) during pregnancy to confirm if the fertilised egg has implanted in the placenta. Here are a few reasons why you need it-

  • To prevent ectopic pregnancies
  • To prevent pregnancy complications like molar pregnancies and miscarriage
  • To check whether or not you’re pregnant
  • To assess the growth and development of the foetus
  • To scan for birth defects and genetic abnormalities
  • As part of other prenatal tests such as Chorionic Villus Sampling


During the First Trimester

During the first trimester of your pregnancy, you will

  • Go through a viability scan and dating scan during the first six weeks, which will be followed up by an NT scan between nine and eleven weeks.
  • Discover your due date through an ultrasound scan.
  • Listen to your baby’s heartbeat for the first time in six weeks.
  • Check how many babies are in your womb and confirm if they are in the right position in the uterus.
  • Check for signs of spotting or excessive bleeding through images produced from the above scans.

During the Second Trimester

During the second trimester, you will

  • Know the baby’s gender (not applicable to India).
  • Assess the foetus’ growth and position inside the womb.
  • Scan for congenital abnormalities and birth defects.
  • Learn whether your baby has Down Syndrome.

During the Third Trimester

A trans vaginal scan is usually avoided in the 3rd trimester, but it may be recommended by your doctor in case of any medical issues. During a regular ultrasound scan in the 3rd trimester, you will

  • Review any anomalies or changes in the anatomy of the baby.
  • Review the position of the baby.
  • Check whether the baby is growing well according to medical diagnostic reports.

How to Prepare for an Ultrasound Scan During Pregnancy

Before you prepare for an ultrasound scan for pregnancy, your bladder will need to be full in order to clearly scan for a high-quality image of the foetus. Make sure you drink two to three-ounce glasses of water, one hour before your scheduled ultrasound scan comes up.

Remember to have a full bladder during your appointment and do not urinate before the scan, especially in the first trimester of pregnancy.

How is an Ultrasound Done During Pregnancy?

The ultrasound scan is a very simple procedure for first-timers. You basically lie down on the examination table and the technician applies a special gel on your abdomen and pelvic area. This gel improves contact between the womb and the transducer so that waves travel properly through your belly. The transducer, which looks like a small wand, is finally placed on your belly, and as it moves, black and white images are captured on the screen. You may be asked to move or hold your breath during this process.

Pregnant lady's ultrasound scan

Once the scan is satisfactory and the images are captured well, the gel is removed from your abdomen, and you will then be allowed to urinate or empty your bladder.

Does a Sonography Hurt?

Under normal circumstances, a sonography doesn’t hurt. However, if you have any pelvic injuries or existing abdominal pain, the pressure exerted by the transducer during the ultrasound might hurt or be a bit painful.

Different Types of Ultrasounds Offered in Pregnancy

There are different types of ultrasounds offered during pregnancy. They are

  1. Transvaginal Ultrasound – A probe is inserted into your vagina and used to capture clear images. This is used during the early stages of pregnancy.
  2. 3-D Ultrasound – A more detailed ultrasound scan that displays the width, height, and depth of the fetus and its organs in images. A special probe and software are used, and it is only available in certain hospitals.
  3. 4-D Ultrasound – Also known as a ‘Dynamic 3-D Ultrasound,’ this scan creates an animated video of the fetus. This motion video captures multiple images of the baby’s facial expressions, movements and even shows the highlights and shadows. However, it requires special equipment.
  4. Fetal Echocardiography– This is used for diagnosing heart problems in the foetus and takes a longer amount of time to complete. It is similar to a traditional pregnancy ultrasound.
  5. Transabdominal Ultrasound – Sends waves through your lower abdomen using a transducer and a special gel. Images are captured in shades of black and white to depict foetal growth and abnormalities.
  6. Doppler Ultrasound – A type of ultrasound that’s used to assess the blood flow to the heart and other major vessels, both in the baby and the mother.
  7. Dating and Viability Scan – Used to confirm pregnancy status in women during the first six to nine weeks.

Some Points to Keep in Mind

  • Ultrasounds are a requirement to judge the health and development of the baby, so don’t miss out on any scheduled appointments.
  • Ultrasounds should only be carried out by a trained professional who has the ability to interpret and analyse the images.
  • If your doctor notices any abnormalities during the ultrasound or wishes to conduct further tests for a clearer look, you may be recommended other procedures.
  • It may be hard for you to identify certain organs during the ultrasound, so you can ask your doctor to point them out.
  • The ultrasound shouldn’t hurt during normal circumstances, so make sure to immediately let your doctor know if you feel any pain.
  • Wear clothing that allows easy access to the abdomen.
  • Make sure to drink plenty of water to prepare for the ultrasound. This helps you finish the scan quicker and also get a better picture.


Here are a few of the most commonly asked questions with regards to an ultrasound scan during pregnancy.

1. Is There Any Problem if the Ultrasound is Performed At Six to Seven Weeks and a Heartbeat is Not Detected?

No. Hearing no heartbeat is normal during the early stages of pregnancy, as long as the foetus is shown to be developing.

2. Are Ultrasound Scans Accurate in Calculating Gestational Age?

An ultrasound scan is accurate in calculating the gestational age of the baby only during the early weeks of pregnancy and not later on.

3. Why Do Some Gynaecologists Schedule Ultrasound Scans Differently?

Some gynaecologists schedule ultrasound scans differently, based on the foetus’ growth and condition during pregnancy. Routine ultrasound scans are done as part of the prenatal testing procedure.

Pregnancy ultrasound scan

4. Are Ultrasound Scans Accurate in Determining the Conception Date?

Any calculations that are done for determining the conception date after an ultrasound are only estimates and not truly accurate. The due date depends on the average length and regularity of a woman’s menstrual cycle.

5. Are Ultrasounds a Significant Part of Prenatal Care?

Yes. Ultrasound scans are used at different stages of prenatal care.

Getting a sonogram in pregnancy is not only sound, but effective too. Ultrasound scans are a necessity to find out whether or not you’re pregnant. If you are, they are used for tracking changes and growth of the fetus. Consult your doctor regarding which type to go for during pregnancy, based on your medical condition and comfort levels.

References & Resources: Healthline

Also Read: Doppler Scan in Pregnancy

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