Ultrasound Scans During Pregnancy: Know When & Why You Need Them

 As an essential part of prenatal care, ultrasound scans during pregnancy are useful tools to monitor appropriate baby development and detect complications, if any. Read to know more

What’s an Ultrasound Scan?

Ultrasound scanning is an imaging technique that is routinely used to assess the health of an expecting mother in various stages of her pregnancy journey. It is a safe, non-invasive procedure that is used to understand the subtleties of a baby’s overall development in the womb. The scanning also offers insight into the potential complications, if any. 

The procedure uses high-frequency sound waves to create images of the fetus, the placenta, and the entire birth environment; so that the doctor can get a clearer picture of the baby’s growth and development. Ultrasound scans are mandatory and as per WHO, ultrasound scans during pregnancy are a part of routine care for the overall wellbeing of the mother and her unborn baby.

Why Should Mothers Undergo Ultrasound Scans?

As a diagnostic tool, these scans are useful for would-be parents and their healthcare providers in several ways. Based on the available data on scan reports, healthcare providers plan an ongoing care regime for the expecting mother. Moreover, the scans can also detect abnormalities, if at all; that can be significant in the days to come in the new mother’s life.

Some of the benefits of ultrasound scans are as follows:

• Monitor fetal size, and decide whether it is appropriate as per gestation age

• Assesses baby’s heart rate and overall growth pattern

• Can tell the would-be parents about twins, triplets, and even multiple pregnancies

• The due date can be ascertained

• Baby position in the uterus

• Location of the placenta and issues like placenta previa

• Overall cervix health

• Can determine amniotic fluid levels

• Allow parents to hear the heartbeat of the baby

• Helps to understand the fetal movement from time to time

Ultrasound Procedures:

There are two types of ultrasound procedures:

1. Transabdominal ultrasound - It is a non-invasive imaging technique that is done over the tummy of the mother to examine the uterus, fetus growth, and overall birth environment during pregnancy.

2. Transvaginal ultrasound - It is an internal examination that inserts the probe into the vagina to assess reproductive organs and the ongoing pregnancy.

Types of Ultrasound Scans During Pregnancy

Having an ultrasound scan during pregnancy is a typical medical procedure; however, the number of scans that need to be carried out on a mother depends upon her overall health and the health of the unborn baby. In usual practice, five types of ultrasound scans are recommended at various stages of gestation to understand fetal growth and development. 

At times, if pregnancy is a high risk, doctors may also recommend other scanning tools to understand the health complications of the fetus and the mother. 

The timing of the first ultrasound usually occurs at the beginning of the pregnancy journey. This scan confirms the would-be parents at the beginning of their pregnancy. Here, both transabdominal and transvaginal sonography can be done to detect a heartbeat, track the initial growth, and assess the overall pregnancy environment of the fetus inside a mother’s womb.

Some of the most common types of ultrasound scans are as follows:

1. Early Pregnancy Scanning - (dating and viability scan) - (7 - 11 weeks)

This scan is an early diagnosis that confirms pregnancy. It is usually done anytime between 7 to 11 weeks of gestation. This scan also helps to assess the due date of delivery. The main purpose of this scan is to confirm fetal heart rate, and whether the fetus is properly implanted in the uterine wall. 

It is the first and most common type of scan where the probe is done over the tummy of the expecting mother. The procedure is painless and most parents choose this scan for peace of mind that the pregnancy is moving in desirable ways.

2. Nuchal Translucency Scan - (11 - 14 weeks)

This scan is commonly done abdominally; however, if additional insights are needed, then transvaginal procedure is also preferred. NT scan, commonly termed; is a vital procedure that helps to assess the following:

• To confirm that the baby’s heart is functioning normally

• Estimates duration of pregnancy

• The length of the baby is assessed to figure out normal growth and development

• Evaluates the fetal structure, including measuring the fluid at the back of the baby’s neck

• To understand the high or low chances of chromosomal abnormalities, if any, such as Down’s syndrome

If any abnormalities surface in this scan, doctors suggest a further probe. Usually, blood work to screen for Down Syndrome is advised and appropriate measures are undertaken to resolve the complications; as much as possible. 

It is important to note that abnormal NT scan readings are not the sole indicator for confirming irregularities in fetal growth. Thus, expecting mothers should never panic and rely on doctors for further investigation and remedy. 

3. Early Anomaly Scan - (14-18 weeks)

This type of scan is usually performed between 14 to 18 weeks of gestation. The purpose is to monitor growth and development; particularly knowing the body parts of the baby. The scan shows the structure of the limbs, face, spine, stomach, kidney, etc. 

This type of ultrasound scan is also known as reassurance scanning. From the name itself, it is clear that the scans reassure the would-be parents and the doctor that the unborn baby is doing fine inside the mother’s womb. 

Since the baby is still in the early growth stage, a follow-up anomaly scan is usually advised between 20 to 24 weeks. This ultrasound scan gives an initial review of the growth status of the internal and external body parts of the baby. 

4. Foetal Anomaly Scan (18 - 24 weeks)

The purpose of this scan is to assess overall growth as per the gestational age. The fetal body is thoroughly examined from head to toe; just to understand the pattern of growth. The scan also shows whether all external body parts and internal organs of the unborn baby are functioning properly. If any abnormalities are found,  treatment options are advised by fetal medicine specialists. 

During this scan, the doctor can identify structural problems in the fetus and suggest remedies. Moreover, the scan is also useful for determining the level of amniotic fluid, placenta position, blood supply to the placenta, etc. Doctors can also assess the risk of preterm pregnancy from this scan. 

5. Growth Scan (24 weeks onwards)

Fetal growth scans are performed anytime after 24 weeks of gestation. These scans are meant to give a detailed well-being report of the developing baby in the third trimester. It shows the baby’s size, estimated birth weight, and overall growth. Apart from this, the scan report gives the following details:

• Baby’s head circumference

• Length of baby’s thigh bone

• Circumference of baby’s abdomen

• Position of the placenta and its maturity levels

• Amount of amniotic fluid

• Baby’s position in the womb

• Movements of the baby

• Blood vessels of the unborn can be checked

• Blood flow through the umbilical cord can be assessed

By using growth charts and comparing the baby’s size, doctors can predict the final delivery date. The specialist can also evaluate the overall development and suggest estimated fetal weight at the time of birth.

Ultrasound scans during pregnancy play a pivotal role in understanding overall maternal health as well as fetal growth. These imaging procedures serve a specific purpose when performed during specific phases of pregnancy; helping parents and physicians make informed decisions for the well-being of the mother and her unborn baby.