Ultrasound In Pregnancy For Wellbeing Of Baby
Ultrasound in Pregnancy
Introduction:
An ultrasound scan during pregnancy is a simple test quite safe for both mother and baby
It’s primarily used to detect signs of abnormalities and monitor the growth of the fetus.
An ultrasound scan sends high-frequency sound waves to the uterus during pregnancy to capture the image of the fetus.
Images in ultrasound scans reveal the developmental phases of the body, often revealing bones and tissues through shades of white and grey.
What can ultrasound scans show during pregnancy?
Ultrasound scans may be recommended at various stages of pregnancy for several reasons. Here are some examples.
To confirm the pregnancy.
To see if there is more than one baby, e.g twins.
To establish the date when the baby is due (baby’s due date).
To rule out an ectopic pregnancy – a pregnancy that implants outside the uterus (womb).
To assess the risk of the baby being affected by certain chromosomal abnormalities, e.g. Down syndrome.
To check on the physical development of the baby and to check that it is growing adequately.
To check the amount of amniotic fluid surrounding the baby in the womb.
To determine the position of the placenta.
To check the baby’s position before delivery.
Expected Ultrasound Results by Week in Early Pregnancy
Gestational Age
Milestone Visible on Ultrasound
4 weeks
Possible endometrial thickening, or no evidence of pregnancy
5 weeks
Gestational sac
5.5 to 6 weeks
Yolk sac
5.5 to 6.5 weeks
Fetal pole; possible fetal heartbeat
6.5 to 7 weeks
Fetal heartbeat
Types of Ultrasound Scans in stages of pregnancy
First Trimester Scan
Second-trimester
Third-trimester scan
Early Pregnancy/Viability scan
NT scan
Anomaly scan
Growth scan / Well being scan
Term scan
First trimester ultrasound scan
Early Pregnancy/Viability scan
An early pregnancy scan is a very important one as it will confirm the pregnancy.
It is a transvaginal scan and is performed between 6-8 weeks or at 10-13weeks of pregnancy.
It also helps in confirmation of the number of embryos, the presence of heartbeat and detection of expected delivery date
Nuchal translucency scan
It also called a first trimester pregnancy screening scan.
The clear space in the back of a developing baby’s neck can disappear by week 15, so an NT scan should be completed in the first trimester between 11 and 14 weeks.
This scan is done in combination with blood tests to determine the baby’s risk of having certain chromosomal abnormalities, such as Down syndrome
To diagnose major fetal abnormalities & structural defects
Second trimester ultrasound scan
Anomaly scan:
Also known as mid-pregnancy scan, this test is usually performed between 18-22 weeks of pregnancy.
To check out for the development of baby and position of the placenta in this scan, assess the amount of amniotic fluid
The doctors carefully go through the baby’s head, face, heart, abdominal walls, kidneys, placenta, and amniotic fluid and check if the development is healthy or not.
Various diseases or conditions like limb abnormalities, brain developmental defects, congenital heart problems can be determined with an anomaly scan.
Third trimester scan :
Growth scan:
As the name suggests, this diagnostic scan is to check for the baby’s overall growth.
It is done around 26 to 40 weeks.
Parameters like
The fetal presentation and position
The fetal size and growth
The volume of amniotic fluid around the baby
The position of the placenta
The blood flow to the baby through the umbilical cord
The activity and movements of the baby are normal
The length of the cervix
It is also highly recommended if you had complications in previous pregnancies, or if you have medical conditions like diabetes or high blood pressure.
Well being scan :
It is done in around 32 weeks
To determine the growth & health of fetus by
Measurement of size of fetal head, abdomen, thigh bone
Calculate estimated fetal weight
Examination the movement of fetus
Evaluation of placental position and appearance
Measurement of amount of amniotic fluid
Assessment of blood flow to placenta & fetus by color doppler ultrasound
Term scan:
It is done at around 36 weeks of pregnancy, this is a final test to ensure that the baby is in good health.
The doctors check for the exact location of the baby and the position of the placenta
Other parameters relating to the baby’s health like the amount of amniotic fluid etc are also checked up.
If everything looks good, the baby is all set for delivery.
Other scans like..
Cervical scan:
It is the transvaginal scan to measure the length of the cervix.
It is recommended for :
Women at high risk for preterm birth
Multiple pregnancies
Abnormalities of uterus
Previous cervix surgery.
Usually carried out at the time of anomaly scan but in women in previous preterm birth, it may be necessary to preform series of scans starting from 16 weeks
Transvaginal scan (TVS)
A TVS may be needed for a clear image of the baby in the very early stages of pregnancy, as embryo is too small to be visible otherwise.
This test is performed between 6-10 weeks of pregnancy and is extremely useful in the diagnosis of ectopic pregnancy, cysts, fibroids, pelvic infection, etc.
Different Types of Ultrasounds Offered in Pregnancy
There are different types of ultrasounds offered during pregnancy. They are
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.
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.
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.
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.
Dating and Viability Scan – Used to confirm pregnancy status in women during the first six to nine weeks.
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