The use of obstetric ultrasound first began in the late 1950s. It is widely used and has become useful in monitoring and diagnosis.
Obstetric ultrasound uses sound waves to produce the fetus’s images inside the uterus and ovaries of the mother. In obstetric ultrasound, ionizing radiation is not used, has no known harmful effects, and maybe a great way to monitor pregnant women and their babies.
These scans use sound waves to create an image of the baby in the womb. These scans are painless. For many women, ultrasound during pregnancy and seeing the baby in the womb, which often moves its arms and legs, is very exciting.
What will happen at the scan?
A trained staff performs most scans called an ultrasound specialist. The scan is performed in a dimly lit room to show good images of the baby. The first thing to do is lie down on a couch. Then lower your skirt or pants to the hips and raise the top of your dress to the chest.
The specialist pours the ultrasound gel onto your abdomen and wraps a tissue around your clothes to protect the gel. This gel ensures good contact between the device and the skin. Produces images of the inside of the body using sound waves. Ultrasound imaging is also called an ultrasound scan or an ultrasound.
A small probe called a transducer and gel is used, which is placed directly on the skin. High-frequency sound waves are transmitted from the probe through the gel into the body. This probe collects bouncing sounds. The computer uses those sound waves to create the image. Because images are captured in real-time, they can show the movement of internal organs and their structure. Also, Doppler ultrasound can check blood flow through blood vessels. This imaging is a non-invasive medical test that helps the obstetrician diagnose and treat medical conditions.
What obstetric ultrasound is offered during pregnancy?
Most women do one or more obstetric ultrasound scans during pregnancy. The two scans most commonly performed during pregnancy are anatomical scans and nuchal scans. Sometimes other scans are done during pregnancy to check the baby’s growth, the baby’s position or the placenta, or other reasons. There are four common steps to perform a scan.
Dating scan
If unsure about your last or irregular period, you may be offered a scan in the first 14 weeks. If you have bleeding in the first trimester of pregnancy, a scan may also be done to ensure the baby is healthy. The baby and the heartbeat are seen on the scan after six weeks. It is not always possible to see the baby before six weeks because it is too small.
Nuchal translucency scan
You are recommended to have a scan between 11 and 14 weeks of pregnancy. The scan results are used to calculate the probability of a problem in the baby, such as Down syndrome. The scan also examines the number of fetuses and is a good way to calculate birth time. Although most of the baby’s body parts have grown up to 14 weeks, it is still small, about 5-8 cm long, so it is difficult to tell if the baby is growing normally at this stage.
Anatomy scan
At about 18-20 weeks of pregnancy, a scan is suggested, called a second-trimester scan. Many important growth problems can be seen by scanning at this stage. This scan is usually the most accurate examination and includes assessing the baby’s growth and placental position. Additional scans may be suggested at this stage. The sonographer will usually explain everything to you when you do the scan. In this scan, you can find out what sex your baby is.
Growth scans
If your pregnancy care provider is concerned about your baby’s development, offer a scan. Not all babies are born the same size. Some babies are smaller than usual. These babies can have problems during childbirth and sometimes have to be born earlier. The scan is suitable for checking the baby’s size but only estimates the baby’s weight. To check the child’s growth, performing two scans at several weeks or more intervals is necessary.
Reasons for an obstetric ultrasound
It is performed during pregnancy for a variety of reasons. Your doctor may order more if you have a problem with a previous obstetric ultrasound or blood test. It may be done for non-medical reasons, such as determining the sex of the baby. While it is safe for both mother and baby, obstetricians do not recommend it for no reason. During the first trimester of pregnancy, an obstetric ultrasound may be done for the following:
- Confirm pregnancy
- Approximate the gestational age of the baby and estimate a due date
- Check the fetal heartbeat
- Check for multiple pregnancies
- Examine the uterus, ovaries, placenta, and cervix
- Diagnose an ectopic pregnancy or miscarriage
- Look for any abnormal growth in the fetus
During the second and third trimesters of pregnancy, an obstetric ultrasound may be done for the following:
- Monitor the fetus’s growth and position
- Determine the baby’s sex
- Confirm multiple pregnancies
- Measure the length of the cervix
- Guide other tests, such as amniocentesis
- Confirm Fetal death in utero (FDIU)
- Check for characteristics of Down syndrome
- Check for congenital abnormalities or birth defects
- Examine the fetus for structural abnormalities or blood flow problems
- Monitor the levels of amniotic fluid
- Determine if the fetus is getting enough oxygen
Types of obstetric ultrasound
More advanced ultrasound techniques may be used if more accurate images are needed. Types of sonography include:
- Transvaginal: Vaginal ultrasound may be done to create a clearer image. It will likely be used in the early stages of pregnancy, and a small ultrasound probe is inserted into the vagina.
- 3-D: Unlike 2-D ultrasound, 3-D sees the width, height, and depth of the fetus and its limbs. It can be especially useful in diagnosing suspected problems during pregnancy. 3-D ultrasound is the same as standard ultrasound but uses special software and a probe to create a 3-D image.
- 4-D: 4-D ultrasound may also be called dynamic 3-D ultrasound. Unlike other types, 4-D ultrasound produces an animated film of the fetus. This creates a better image of the baby’s face and movements.
- Fetal echocardiography: A fetal echocardiogram is done if your doctor suspects your baby has a congenital heart defect. This test may be similar to a normal pregnancy ultrasound but may take longer. This captures a deep image of the fetal heart, which shows the heart’s size, shape, and structure.
What is a doppler ultrasound?
Doppler ultrasound uses high-intensity sound waves to detect blood circulation in the baby, uterus, and placenta. Color Doppler is the standard method for examining blood vessels. Doppler is based on the frequency of sound; Depending on the speed and direction of red blood cells in the arteries, the speed at which the waves return to the device varies.
When these ultrasonic waves return to the device, color images are recorded on the monitor. This method examines the umbilical cord’s blood flow, fetal brain vessels, and the mother’s uterus. And based on that, the amount of oxygen and nutrients that are provided to the fetus can be determined.
In cases where less oxygen reaches the fetus due to placental or uterine vascular disorders, the fetal blood becomes acidic. As this process progresses, cardiac arrest and fetal death eventually occur.
Therefore, pregnancy complications and fetal death can be prevented by performing a color Doppler ultrasound and timely diagnosis of these disorders.
What are the benefits vs. risks of obstetric ultrasound?
Obstetric ultrasound has many benefits, including:
- Most Obstetric ultrasound scanning is noninvasive
- It is widely available, less expensive, and easy to use than other imaging modalities
- This scan provides a clear image of soft tissues not well represented on X-ray images.
- It has been used to assess pregnancy for nearly four decades, and there is no credible evidence of harm to the pregnant mother or fetus.
No known standard diagnostic effect of obstetric ultrasound has been obtained. Some factors may limit the information you receive from an obstetric ultrasound. They are:
- A very small or big baby
- Overweight or obese
- Low amount of fluid around the baby
- Position the baby
Dr. Arjang Naim uses the latest devices worldwide to perform an ultrasound for pregnant mothers to maintain the mother and fetus’s health.
Additional questions
- What are the three types of ultrasounds?
Echocardiogram, which examines the heart.
3D ultrasound shows a three-dimensional picture of the inside of the body.
4D ultrasound, which creates a three-dimensional picture in motion.
- What does a vaginal ultrasound show?
Transvaginal ultrasound is an examination of the female pelvis. This ultrasound shows any abnormality in the uterus, cervix, endometrium, fallopian tubes, ovaries, bladder, or pelvic cavity.
- Why is nuchal translucency done at 12 weeks?
This combination test is a highly accurate non-invasive screening test available to help identify fetuses at risk for Down syndrome as well as other chromosomal abnormalities and some major structural abnormalities.
- When does the fetal heartbeat start?
A baby’s cardiovascular system develops five weeks after conception or three weeks after conception. The heart starts beating a little later.
- How many ultrasounds are too many in pregnancy?
Most pregnancies only require two standard ultrasounds, but if the mother or baby is at risk of complications, the doctor may perform more ultrasounds.
References
https://www.ncbi.nlm.nih.gov/books/NBK470450/
https://www.healthline.com/health/pregnancy/ultrasound
https://my.clevelandclinic.org/health/diagnostics/9704-ultrasound-in-pregnancy
https://www.marchofdimes.org/find-support/topics/pregnancy/ultrasound-during-pregnancy