First Trimester Scans For Your Growing Baby by Dr Prerna Jhawar

6 min read

Reviewed by Dr Prerna Jhawar MBBS, MS(Obstetrics and Gynaecology),
FFM Consultant, Fetal Medicine,
Rainbow Children's Hospitals, Bengaluru

Dr Prerna Jhawar

Dr Prerna Jhawar is a Fetal medicine expert with 12+ years of experience. As a Fetal medicine expert, Dr Prerna takes care of babies while they are still in their Mother’s womb! Sharing the More

Written by Aparna Hari

Aparna Hari

First Trimester Scans

Congratulations on your pregnancy! You become a mom right from the time you see those pink lines in your home pregnancy kit. Visits to the doctor and regular scans become normal thereafter – all for the benefit of both the mother and the growing fetus. First trimesters scans are an important part of your first trimester checkups.

A scan reveals whether your baby is growing as expected. While 2D scans are the most common, 3D and 4D scans during pregnancy are normal too. The frequency of the scans will be determined by your gynecologist. While these scans will continue throughout your pregnancy, in this blog, you will get to know everything about first trimester scan for your growing baby.

In This Article

What is First Trimester of Pregnancy and What Types of Scans Are Performed?

A pregnancy lasts for about 280 days or 40 weeks. These weeks are grouped into three trimesters. The first trimester of pregnancy is the time in between conception and week 12 of pregnancy.

Usually, doctors will ask you to go for two types of scans when you are in your first trimester.

  • A dating and viability scan that is done between six and nine weeks of pregnancy.
  • Nuchal Translucency Scan (N T Scan) that is done between eleven and thirteen weeks of pregnancy.

Importance of First Trimester Scan For First Time Pregnancy

If you are a first-time mom, you will have many inhibitions about first trimester scanning (why and how it is done). Please understand that you are not alone, and your doctor is always there to answer your queries.

The first trimester scan is of utmost importance as it helps your doctor to understand a lot about your growing baby. Here are a few things you and your doctor will learn from these cans

  • Whether the little one is in the right position inside the uterus.
  • If he is growing well or not, hear his heartbeat, calculate your due date etc.
  • Hear Baby’s First heartbeat.
  • Calculate your due date
  • Check whether you have a single baby or twins or multiple gestations.

How Many Scans Are Done in the First Trimester?

pregnant women with scan reports

Generally, two scans are done during the first trimester – a dating and viability scan, between six and nine weeks and a Nuchal Transluency scan (NT scan) between eleven and thirteen weeks.

Can You Hear Your Baby’s Heartbeat at 6 Weeks?

Your baby’s heart begins to beat from around 6 weeks of pregnancy. However, sometimes it may be earlier and sometimes later as well. It is normal to be unable to detect a heartbeat until closer to 6 weeks.

Can You Hear Your Baby’s Heartbeat at 7 Weeks?

Your doctor can find your baby’s heartbeat in the 7th week as well. Sometimes the baby’s heartbeat will not be clearly audible until seven or eight weeks.

[Read : Your Baby’s Heartbeat – Everything You Need to Know]

List of Scans During Routine Pregnancy

 Scans During First Trimester Pregnancy

The list of scans to be done during pregnancy usually varies from person to person. A low-risk pregnancy may have four or five scans during the entire pregnancy.

Here is a list of the routine scans:

1. Dating And Viability Scan

This scan is done between 6 and 9 weeks. A dating scan is performed to establish the gestational age of the pregnancy, besides understanding the heartbeat, and detecting any unusual features of the uterus like the presence of fibroids if any.

2. NT Scan or Nuchal Translucency Scan

Nuchal translucency (NT) scan sometimes called the early morphology scan is done between 11 and 13 weeks. This scan is done to measure the baby’s size and thickness of fluid behind the neck to estimate the chances of the growing baby being born with genetic disorders.

3. Anomaly Scan

The Anomaly scan is done between 18 and 20 weeks. The scan looks at the baby’s bones, heart, brain, spinal cord, face, kidneys, extremities, and abdomen.

4. Growth Scan

The Growth scan or fetal well-being scan will be done between 28 and 32 weeks. This scan, as the name suggests, determines the growth, blood flow and fluid around the baby.

5. Doppler Scan

The Doppler scan shows the rate of blood flow in the umbilical cord and the brain of the baby.

However, you may need to have more scans if:

  • You are 35+.
  • You are carrying twins or more.
  • There is a difference in your baby’s expected size based on your due date and the actual size as measured in a scan.
  • Any complications with the pregnancy like ageing placenta, low or high levels of amniotic fluid, an irregularity in blood circulation in the umbilical cord, a sudden fall in the growth of the baby, etc.
  • You have high blood pressure, gestational diabetes or any medical problem which may cause any complications.

[Read : All About Chorionic Villus Sampling (CVS)]

Fetal Development at First Trimester Scan

Right from the time you conceive your baby till the time of delivery, your growing baby goes through several stages of development (from a fertilized egg to a garlic bulb-size baby) in the womb before he or she is born. The early scan can reveal some fantastic things about fetal development in the womb.

Week   Fetal Development in First Trimester Scan
Week 5 The ultrasound expert generally observes a small sac that looks like a black hole because it is filled with amniotic fluid. This is the gestation sac. The expert can identify the location of the sac to determine whether it is in your uterus or not. This is to make sure that there is no sign of an ectopic pregnancy. She may ask you to come back for another scan in one or two weeks.
Week 6 The yolk sac is attached to the embryo and contains nutrients to feed the fetus while it is developing. At this time, the head to bottom length of the embryo is measured to calculate your due date.
Week 7 A tiny embryo with a heartbeat can be heard.
Week 8 The developing embryo (measuring up to 1cm-2cm) should be easier to see on the scan by now. It will grow rapidly in the coming weeks.
Week 10 Your growing baby now measures 3cm and you can see and hear her heartbeat. In the next few weeks, the doctor may advise you for a Nuchal Translucency scan (NT scan). This scan estimates the risk of Down’s syndrome and other abnormalities.

What Will the Doctor Examine at the First Trimester Ultrasound Scan?

doctor examine scan report
It is advisable to plan a visit to the doctor/gynecologist when you first learn that you are pregnant. The doctor will then take note of your entire health history and perform a full physical and pelvic exam. Usually, at this time, your doctor may perform an ultrasound scan to confirm the pregnancy. The ultrasound scan is one of the routine tests conducted during pregnancy which determines the normal development of your baby and detects any fetal abnormalities as well. This is also done to calculate the due date and determine the heartbeat of the baby. It is delightful to see the little blob with a heartbeat that will soon become your baby!

Interestingly, the ultrasound scan also helps your doctor to understand how many babies you are carrying and if there are twins, the scan will help to identify whether they are identical or not.

In a nuchal translucency scan, the doctor will look at the thickness of fluid behind the neck, the formation of the nasal bone, flow across the tricuspid valve of the heart of the fetus and flow in a small blood vessel called ductus venosus. These all are markers of chromosomal abnormality (genetic problem) and if normal, will reassure that your baby is at very low risk of having a genetic problem.

Once you sail smoothly through the first trimester, it is time for you to enter the second trimester with your baby.

[Read : First Ultrasound During Pregnancy]


1. What Scans Are Done in The First Trimester of Pregnancy?

A dating and viability scan between 6 and 9 weeks of pregnancy and an NT scan between 11 and 13 weeks of pregnancy are the two scans done during the first trimester.

2. What do They Check For at 12 Week Scan?

The 12-week scan is the NT scan or the Nuchal Translucency scan. In this, your doctor will screen you for the possibility of genetic anomalies such as Down syndrome, trisomy 13 or Patau syndrome and trisomy 18 or Edwards syndrome.

Read Also: Second Trimester Anomaly Scan For Your Growing Baby

Aparna Hari,MBA in Marketing,P.G. Diploma in Human Resource Management from IGNOU Bachelor of Sciences (Home Science) from Nagarjuna University

Her experience in impactful writing combined with her background in Home Sciences makes Aparna the perfect candidate for content writing in the pregnancy and parenting niche.Read more.

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