Ultrasound can tell what? Diagnosis of the fetus at each stage of pregnancy.

Ultrasound is one of the most commonly discussed methods when a mother is pregnant because it is highly safe and can be performed as often as necessary. This high-frequency sound wave test is not only useful for determining the baby's gender and monitoring fetal growth but can also be used to diagnose various abnormalities.

However, many people may not know what an ultrasound actually is, what its different forms are, and how it works. Besides checking the baby's gender and appearance, ultrasound is also important for pregnant mothers. If there is a plan for an ultrasound, how should one prepare for it?

Ultrasound is a medical diagnostic procedure that uses high-frequency sound waves, above 20,000 Hz. This ultrasound wave has now been developed into a medical tool used for diagnosing various diseases, including checking the health of a fetus in the womb.

The principle of high-frequency sound wave testing, or Ultrasonography, is to send high-frequency sound waves from the probe (Transducer). The sound waves will collide with various tissues, which have different abilities to transmit and reflect the waves.

The probe receives the reflected sound waves at different levels, which indicate the density and depth of the tissue. The received signals are then processed to create an image used for diagnosing diseases, checking the fetus in the womb, or as a tool to help surgeons see the body during surgery.

1. 2D Ultrasound.

2D ultrasound creates cross-sectional images, one slice at a time, based on the high-frequency sound waves sent out in a horizontal plane. This provides two dimensions: width (dimension 1) and length (dimension 2). The resulting image is a black-and-white shadow showing the fetus in the womb, but it cannot clearly show the baby's face. Parents may not fully understand the image and may have difficulty interpreting it as described by the doctor.

A 3D ultrasound machine is more complex than a 2D ultrasound. It displays width, height, and depth, with the probe sending high-frequency sound waves at different angles and receiving the reflected sound signals. These signals are then processed and analyzed using complex computer software. The resulting image shows the surface of the fetus or the internal organs, allowing parents to see a more realistic shape and form of the fetus, including a clearer view of the face and details compared to a 2D image. This makes it easier to predict what the baby will look like after birth and helps parents understand the image more clearly than with a 2D photo.

A 4D ultrasound machine is similar to a 3D ultrasound, but with improved processing and an added fourth dimension: "time." In addition to seeing the fetus in 3D, a 4D ultrasound takes the 3D images and arranges them into a moving sequence, allowing real-time visualization of the fetus using sound waves. This gives the impression of seeing the fetus in the womb in real-time.

This type of ultrasound helps study the fetus's behaviors, such as yawning, sucking its thumb, opening its mouth, moving fingers, or even smiling, with clear details. It also provides additional information and details, especially regarding surface abnormalities such as cleft lips or certain types of skin tumors, which can be useful for diagnosing specific conditions.

Advantages of prenatal ultrasound:

• It does not cause pain during the procedure.

• The ultrasound machine can capture soft tissue images more clearly than X-rays.

• Parents can find out the baby's gender when the pregnancy reaches 12 weeks, or more accurately at 16 weeks.

• The examination time is shorter since the body and organs of the fetus can be seen clearly from the images stored on the computer.

• The external features of the fetus, such as the face, arms, legs, and fingers, can be seen clearly.

• The behaviors of the fetus can be observed clearly, such as yawning, sucking its thumb, smiling, swallowing amniotic fluid, blinking, or moving its fingers.

It cannot be used to examine organs that contain air, such as the lungs or stomach.
It also cannot be used to examine organs that are made of bone or blocked by bone, as the bones will reflect all the sound waves, preventing them from penetrating to the other organs.

First Trimester (0-14 weeks of pregnancy):
The first ultrasound during pregnancy confirmation will determine whether the pregnancy is in the uterus or ectopic. It will also help establish the pregnancy's gestational age by using the last menstrual period and measuring the length of the embryo from the ultrasound image. The doctor will also examine other pelvic organs, such as the uterus and ovaries. Ultrasound images at different stages of pregnancy hold different significance.

For example, the ultrasound at 1 month will show the thickened uterine wall to support embryo implantation, but the pregnancy sac will not be visible yet. In the middle of the first trimester, an ultrasound at 2 months will show the fetus starting to take shape.

Second Trimester (14-28 weeks of pregnancy):
The period between 18-22 weeks is the best time to assess the fetus's development from the ultrasound image. During this time, ultrasounds can assess the completeness of various organs, and each week's ultrasound can evaluate most of the following:

• Skull and brain

• Facial structure, eyes, palate, lips

• Chest, lungs, heart structure, heart vessels, and blood circulation

• Abdomen, stomach, intestines, kidneys, bladder

• Gender

• Bone structure, spine, arms, legs, hands, feet, fingers, and toes

• Amniotic fluid volume

• Estimated fetal weight

• Placenta and umbilical cord attachment

• Common abnormalities like cleft lip, palate, brain abnormalities, heart defects, and low-lying placenta

If congenital abnormalities are detected at this stage, doctors may recommend further tests, such as amniocentesis or cord blood sampling, to check for chromosomal abnormalities, along with consultations from specialists to plan care during pregnancy, labor, and after delivery.

Third Trimester (28 weeks until delivery):
In the third trimester, ultrasound helps assess the baby's weight to estimate pre-delivery weight, fetal position, amniotic fluid volume, and it can confirm the placenta's position to check for low-lying placenta. This assessment is crucial to evaluate the appropriate delivery method and the fetus's well-being. An ultrasound can detect any issues that may arise in the third trimester, emphasizing the importance of ultrasound in monitoring fetal development.

For abdominal ultrasound, it is recommended to refrain from eating, drinking, and taking any medications at least 6 hours before the examination.

For pelvic ultrasound, the patient needs to hold their urine during the examination. It is advised to drink plenty of water before the procedure because the water in the bladder acts as a medium to transmit sound waves to other organs in the pelvic area located behind the bladder.

There are two methods for pregnancy ultrasound: abdominal ultrasound and vaginal ultrasound. Each method has the following steps:

Abdominal Ultrasound:

• The mother lies on the examination table, and the area of the abdomen is cleaned.

• Ultrasound gel is applied to the abdomen in the area to be examined, which helps the high-frequency sound waves pass more effectively.

• The ultrasound probe is placed on the abdomen, and it is slowly moved to the desired position.

• The sound waves emitted by the probe are reflected back to the receiver, and the result is displayed on the screen immediately.

• The doctor will explain the images, provide results, and offer advice to the mother.

• Normally, this method takes about 30 minutes to 1 hour.

Vaginal Ultrasound:

• For mothers in the early stages of pregnancy (approximately 7-12 weeks), the pregnancy sac is still small, making it difficult to get a clear image through abdominal ultrasound. Additionally, mothers who are overweight may find abdominal ultrasound results unclear, so vaginal ultrasound can be used instead.

• The doctor will insert the ultrasound probe into the vagina (the probe used for vaginal ultrasound differs from the one used for abdominal ultrasound).

• The probe gets closer to the uterus and ovaries than abdominal ultrasound, allowing the doctor to see clearer images of the uterus and ovaries.

Ultrasound can show us the development of the fetus in all aspects, and a detailed ultrasound can help identify certain abnormalities of the fetus, even if they are small. Many times, you may hear the doctor mention ultrasound readings using abbreviations. New mothers should study these abbreviations to better understand what the doctor is explaining. Here are the common ultrasound readings:

• CRL = Crown-rump length, the length of the embryo from head to bottom, used to calculate gestational age.

• BPD = Biparietal diameter, the width of the baby’s head.

• HC = Head circumference, the measurement around the baby’s head.

• AC = Abdominal circumference, the measurement around the baby’s abdomen.

• FL = Femur length, the length of the baby’s thigh bone.

• EFW = Estimated fetal weight, an estimate of the baby’s weight.

• NT = Nuchal translucency, the thickness of the tissue at the back of the baby’s neck, used for screening Down syndrome.

• EDD = Estimated due date, the approximate date of delivery.

• EFW1 (HAD-1) = Estimated fetal weight based on the Haddlock formula.

• EFW2 (SHEPARD) = Estimated fetal weight based on the Shepard formula.

• FHS = Fetal heart sounds, the heart rate of the baby.

• Gestational sac = The pregnancy sac.

• Fetal cardiac pulsation = The fetal heart rate.

• Placental site = The location of the placenta.

• Placental grading = The appearance of the placenta.

Since the introduction of ultrasound in medical practice, there have been no reports of side effects from ultrasound examinations. Whether performed frequently or infrequently, it is not harmful, as long as the examination is necessary. For general pregnancy checks, ultrasounds are typically done once a month, or in cases that require closer monitoring, they may be done every two weeks, depending on the specific needs of each patient.

However, everything has its limitations. Some diseases cannot be detected with ultrasound, and sometimes the baby's position may not allow for clear imaging during the ultrasound.

Can you skip ultrasound during pregnancy?

It is possible, but you won't know if the pregnancy sac is implanted in the right place or how healthy and well-developed the baby is, or if there are any abnormalities. It is not recommended because if any complications arise, the doctor may not be able to address or treat the issue in time.

When should a pregnant woman have an ultrasound?

An ultrasound should be done as soon as you know you're pregnant. The doctor will perform the ultrasound to check whether the pregnancy sac is in the correct position to avoid mistakes like an ectopic pregnancy. It's important to have an ultrasound as soon as pregnancy is confirmed.

Is it dangerous to have ultrasounds frequently?

Since ultrasound machines have been used in medicine, no side effects or dangers have been reported. Therefore, frequent or infrequent ultrasounds do not pose a risk to the baby.

Can an ultrasound detect abnormalities or disabilities in the baby?

Ultrasounds can detect abnormalities in the baby, and it is recommended to have the ultrasound between 18 to 22 weeks of pregnancy to assess the development of the baby.

Is an ultrasound necessary at 1 month of pregnancy?

At 1 month of pregnancy, an ultrasound is not necessary because the baby is not fully formed yet. You'll only see a small mass inside the uterus.

Can ultrasound results be inaccurate?

Ultrasound results can be inaccurate due to equipment malfunction or if the ultrasound is performed by a non-specialized doctor. Therefore, it is important to choose a well-certified service provider and experienced doctor for the best results.

Is it okay to have an ultrasound only during the last weeks of pregnancy?

Ultrasound should be performed from the early stages of pregnancy to monitor the baby’s development and to detect potential abnormalities. Waiting until the last stages may prevent you from addressing any problems that could arise in time.

Ultrasound is a medical diagnostic test that uses high-frequency sound waves (above 20,000 Hz) to examine the body, including pregnancy. There are three types of ultrasounds: 2D, 3D, and 4D.

When preparing for an ultrasound, it is recommended to refrain from eating, drinking, and taking medications for at least 6 hours prior to the exam. If it's a pelvic ultrasound, you should also hold your urine during the test, as the fluid in your bladder helps transmit the sound waves to other organs.

For expectant mothers between 11-13 weeks pregnant, it's advised to have an ultrasound to confirm the pregnancy's age by measuring the length from the head to the coccyx. This will provide a more accurate due date. If any parents are interested or have questions, they can inquire further via Line: @beyondivf