Overview of Sonography 1st Trimester Assessment, Protocols, and Interpretation
Ultrasound is a method commonly used to check the health and development of a baby during pregnancy. It’s often used to recognize any complications that might occur during pregnancy. These could be things that a woman would seek help for at an emergency department or a prenatal clinic. While many women use home pregnancy tests, some only find out that they are pregnant during a routine check-up. In fact, in the US, about one-third of pregnant women visit the emergency department at least once during their pregnancy.
Most pregnant women will have at least one ultrasound scan during their pregnancy. If only one ultrasound can be made, it’s generally done during the second trimester (18 to 22 weeks into the pregnancy). This is to check for any abnormalities or issues with the baby’s growth. But it’s not necessary for all pregnancies to have an ultrasound in the first trimester to confirm they are viable.
If there are any high-risk situations, like the mother being of advanced age or expecting twins, or if the pregnant woman experiences uneven menstrual cycles or bleeding, more than one ultrasound might be performed. The first of these could be in the late first trimester, between the 10th and almost 14th week of pregnancy. Also, ultrasounds done before the 10th week are common and can still provide accurate information for most necessary medical decisions.
Anatomy and Physiology of Sonography 1st Trimester Assessment, Protocols, and Interpretation
The uterus is an organ found in women’s bodies. It is located between the bladder at the front and the rectum at the back. In most women, the uterus leans a little towards the front of the body. However, some women have a uterus that leans back or to the sides.
The uterus connects to the cervix, which is the entrance to the uterus from the vagina. Using a tool known as a transabdominal transducer, doctors can see a bright stripe running down the middle of the uterus, showing where it connects with the cervix.
On either side of the uterus, you can find the ovaries. These typically sit between the sides of the uterus and the blood vessels that supply the pelvic area. This location can change in women who have given birth more than once. The ovaries and uterus are connected by the fallopian tubes. Doctors pay special attention to these structures as these are where pregnancies can implant outside the uterus, which is known as an ectopic pregnancy. Ovaries normally appear a little bit darker when viewed with ultrasound compared to the surrounding tissue and contain small fluid-filled spaces known as follicles.
In the early stages of pregnancy, doctors look for certain signs on the ultrasound. The first is the gestational sac, an empty-appearing structure that becomes visible around a month after conception. It starts off being quite small but grows as the pregnancy progresses. The gestational sac is surrounded by two bright rings, known as the double decidua. Some doctors prefer to also see a yolk sac, which is another bright ring with an empty center before confirming a pregnancy. The yolk sac typically becomes visible about a month after conception under ultrasound.
A structure known as the fetal pole, which is the early development of the fetus, is typically seen about 6 weeks into the pregnancy. It is located next to the yolk sac. Around the same time, a baby’s heartbeat can usually be detected. By the seventh week of pregnancy, the amnion, which is the innermost layer of the placenta and contains the amniotic fluid, becomes visible and appears as a bigger bright ring within the gestational sac of the fetal pole. The amnion grows as the baby starts producing urine around week 10 and merges with the outermost layer of the placenta (chorion) by weeks 14 to 16.
Why do People Need Sonography 1st Trimester Assessment, Protocols, and Interpretation
In the first three months of pregnancy, a doctor might use ultrasound technology for several reasons. They could be checking for things like unexplained pain, possible twin pregnancies, unexplained bleeding, abnormal cells that could indicate a growth, any unusual results from growth check-ups, signs of an abnormal neck thickness in the fetus, unusual growths or abnormalities in the uterus. Also, they might use it to get a snapshot of the placenta’s health. Sometimes, even if the pregnant person feels fine, they might still be asked to have a routine ultrasound if it’s possible, to make sure the pregnancy is progressing normally.
If a pregnant person reports bleeding, which is common and affects about 1 in 4 individuals, the cause of the bleeding might be due to an injury or it could be for an unknown reason. In these cases, a specific type of ultrasound called a Focused Assessment with Sonography in Trauma (FAST) exam might be employed. This could happen if the person has sustained abdominal injuries in the first stages of pregnancy, or shows signs of internal bleeding like low blood pressure, fast heart rate or other worrying symptoms. A FAST exam could be done before a regular pregnancy-related ultrasound in these cases. If this particular ultrasound shows any evidence of free-flowing fluid in the body, an immediate surgical procedure could be needed. If the same result is found in a non-injured, pregnant patient, it might mean that the pregnancy is located outside of the uterus, which is a condition known as an ectopic pregnancy.
Ultrasounds in the first three months of pregnancy also help doctors to monitor the baby as they develop. In some countries, doctors use them to check for genetic disorders by examining the thickness of the baby’s neck between the 11th and just before 14 weeks of pregnancy. Ultrasounds can also be used to confirm if the person is pregnant with more than one child, check for any visible abnormalities in the fetus and to watch the baby’s heart function.
When a Person Should Avoid Sonography 1st Trimester Assessment, Protocols, and Interpretation
There aren’t any medical reasons why you can’t have an ultrasound through the abdomen or the vagina in the first three months of pregnancy, unless you refuse to have one. However, doctors should talk to patients about what a first trimester ultrasound can and cannot show before doing the test.
Equipment used for Sonography 1st Trimester Assessment, Protocols, and Interpretation
When getting an ultrasound in the first three months of pregnancy, the medical professional—also called a sonographer—is going to use a method known as two-dimensional ultrasound. This ultrasound might seem pretty advanced to you: it can adjust its power, capture frozen images, zoom in and out, measure things electronically, and save or print images.
When scanning your uterus and other organs in your lower abdomen, the sonographer needs to use a specific technology to see deep into your body. They use something called a curvilinear transducer, which works very well for this. The sonographer may also ask you to have a full bladder. This is because a full bladder moves the uterus backward, which helps create a “window” to see the body structures below the bladder more clearly.
Sometimes, the sonographer might even manage to get a good view of a very early pregnancy by looking through the abdominal wall with a high-frequency, linear probe when your uterus is naturally tipped forward—provided the area they need to look at isn’t more than 6 cm below the skin.
If it’s difficult to see everything clearly from outside your body, the sonographer will perform a different kind of ultrasound called a transvaginal ultrasound, in which a probe is inserted into the vagina. If this is the case, you’ll need to empty your bladder first, and the probe is covered in a clean sheath before use. The sheath is filled with an ultrasound gel on the inside, and a lubricating jelly on the outside. The jelly helps make insertion easier and more comfortable.
It’s very important to confirm that the sonographer doesn’t use ultrasound gel on the outside of the sheath because it can irritate your body’s tissues. They should also thoroughly clean the probe after it has been used, following strict guidelines for high-level disinfection. A simple wipe with a cleaning cloth would not be enough.
Who is needed to perform Sonography 1st Trimester Assessment, Protocols, and Interpretation?
Doctors, nurse practitioners (a special type of nurse who can diagnose conditions and prescribe treatment), physician assistants (medical professionals who can diagnose illnesses, give treatment, and analyze test results), ultrasound technicians (they operate equipment that creates images of the inside of your body), and other trained healthcare providers can perform your obstetric ultrasound exam. This exam is a type of imaging test, like an X-ray or CAT scan, but it’s specifically for pregnant women to show a picture of a baby in the womb.
Preparing for Sonography 1st Trimester Assessment, Protocols, and Interpretation
For the ultrasound scan from your belly (known as a transabdominal ultrasound), you’ll be asked to lie down comfortably with your lower stomach area exposed. Having a full bladder can help improve the visibility of your womb and structures located deep inside the bladder to the doctor. If the clinic has a facility for it, warm gel might be applied on your lower belly area to enhance the ultrasound images.
For a transvaginal ultrasound scan, which is done via the vagina, you’ll be asked to empty your bladder before your scan. This is because a targetted probe in the vagina provides a close-up view of the pelvic structures, making it easier to examine these organs. Ideally, a bed with supports for your legs (stirrups) can position you comfortably during the procedure. However, if this isn’t available, a towel or bedpan can elevate your hips to make the process comfortable.
The probe used will be safely covered and lubricated with a water-soluble gel. Keep in mind, this scan is a little invasive, so a third person, (a chaperone), will be there for the entire time during your examination to ensure your comfort and safety.
How is Sonography 1st Trimester Assessment, Protocols, and Interpretation performed
A transabdominal ultrasound is a type of scan that uses sound waves to create images of your organs. It’s often used during pregnancy to check on the baby. This ultrasound is done with a curvilinear probe, which is a handheld device that’s moved around on your belly. The probe is placed on your lower belly, above your pubic bone. It helps to see your bladder, uterus, and cervix in detail. It also helps to identify your ovaries, which can be located by moving the probe sideways.
A high-resolution probe can be used if needed to see the baby in early pregnancy. But sometimes, the fetus can be hard to see with a transabdominal ultrasound – in such cases, a transvaginal ultrasound may be done.
A transvaginal ultrasound is an ultrasound done through the vagina rather than the belly. It’s done with an endocavitary transducer, which is specially designed for insertion into the body. It’s covered with a probe cover and ultrasound gel to make the insertion easy and comfortable. This method allows the doctor to see your uterus, cervix, and ovaries in greater detail. Especially, it helps to see the baby if it’s hard to see with a regular ultrasound.
If a gestational sac (where the baby is growing) is seen, the ultrasound tech will make sure it’s inside your uterus. There’s a chance it could be growing somewhere else, which is an abnormal condition called an ectopic pregnancy.
The ultrasound also measures the size of your gestational sac and your baby. These measurements help the doctor to determine your due date. If your baby’s heartbeat can be seen, it will also be checked. The heartbeat is a good sign that the pregnancy is going well.
Possible Complications of Sonography 1st Trimester Assessment, Protocols, and Interpretation
First-trimester ultrasound, which is a scan done in the first three months of pregnancy, can sometimes cause potential issues. These might include feelings of discomfort or pain in the lower belly area, bleeding from the vagina, and getting an infection.
What Else Should I Know About Sonography 1st Trimester Assessment, Protocols, and Interpretation?
Getting an ultrasound during the first-trimester of pregnancy is critical to confirm the location and viability of the pregnancy. This examination can also establish the precise age of the pregnancy. Seeing a gestational sac (small fluid-filled balloon) in the uterus confirms a pregnancy taking place in the uterus. However, it could be misleading just to see fluid in the uterus without seeing other structures like the yolk sac (a nourishing structure for the fetus) or fetal pole (the early structure that will become the baby).
If these structures aren’t seen clearly, it’s best to conduct another ultrasound in a week to ten days. During this period, a doctor might also regularly measure a hormone produced during pregnancy called human chorionic gonadotropin.
Ectopic pregnancies, when a pregnancy starts growing outside the uterus, are a risk. They can cause severe conditions, including death in some cases. Thus, doctors will look out for symptoms such as bleeding, pain, or signs of shock during early pregnancy.
In an ultrasound examination, viability refers to whether the fetus is active and has a heartbeat. For example, if you see an empty gestational sac (a fluid-filled structure that should house the baby) that’s more than 25mm wide, it indicates the pregnancy isn’t viable. A heartbeat is usually detected once the embryo measures 2mm or more and means the pregnancy is viable. On the other hand, if an embryo measures over seven centimeters but has no heartbeat, it’s a sign of a failed pregnancy. Additionally, if two ultrasounds done 7 to 10 days apart don’t show an embryo, it could also indicate a failed pregnancy.
An oversized yolk sac (greater than 7mm), an amnion (a protective sack for the baby) seen next to the yolk sac without an embryo inside, or the gestational sac being too small compared to the embryo, can all suggest pregnancy failure. A subchorionic hemorrhage is another sign doctors look for. This is when there’s fluid, not related to the gestational sac, in the uterine wall, which can increase the risk of pregnancy loss.
Ultrasound can also help determine the exact gestational age (how far along the pregnancy is) using a measure called crown-rump length, which measures the size of the fetus from its head to its bottom. This can help reduce unnecessary induction (artificially starting) of labor for pregnancies that are believed to be overdue but, in actuality, aren’t.
Measurements of nuchal translucency, or the thickness of the neck of the fetus, are being evaluated as an additional tool for early detection of possible abnormalities in the fetus.
In rare cases, an ultrasound might pick up on trophoblastic disease, also known as molar pregnancy. This is when an abnormal growth develops in the uterus. Doctors identify it through an ultrasound as a bright structure within numerous small cysts. If such conditions arise or are suspected, doctors might ask for additional consultation.
