Overview of Ectopic Pregnancy, Ultrasound
An ectopic pregnancy, where the fertilized egg implants somewhere outside the uterus, can be difficult to spot. In fact, about 40% of these pregnancies aren’t identified at first sight. It’s also hard to determine just through medical history or an initial physical examination, as those methods aren’t always accurate in diagnosing this condition. Research has shown that even skilled gynecologists may miss half of the growths caused by ectopic pregnancies during a physical examination because of the complexity of this condition.
In order to diagnose an ectopic pregnancy, doctors usually rely on lab tests and special imaging tests. For imaging, ultrasound is commonly used. Ectopic pregnancies might not always show up during an ultrasound, but if an ultrasound can confirm a pregnancy inside the uterus (known as an intrauterine pregnancy), then it is very unlikely that an ectopic pregnancy exists as well.
When performing an ultrasound, there are two methods doctors may choose. The first one is a transabdominal ultrasound, which is simpler but slightly less precise. It involves moving a transducer across the abdomen to scan for images. The second method is an endovaginal ultrasound. This method is a bit more invasive since the transducer is inserted into the vagina, but the images produced are often clearer and can better help doctors diagnose an ectopic pregnancy.
Anatomy and Physiology of Ectopic Pregnancy, Ultrasound
The introitus, or the entrance to the vagina, leads to the cervix, which is the lower part of the uterus that connects it to the vagina. Attached to the uterus are two tubes called fallopian tubes, which have little fringe-like extensions called fimbria at the end leading to the ovaries. Knowing these details helps doctors to identify what is normal and abnormal in an ultrasound scan of a woman’s reproductive system. This is essential in cases like an ectopic pregnancy. In such a case, a gestation sac, where the baby grows, can be seen in the ultrasound.
Where an ectopic pregnancy usually occurs can differ based on how the pregnancy happened. In a naturally occurring pregnancy, around 95% of the time, the pregnancy develops in the fallopian tube. A very small percentage, 1.4%, develop in the abdomen, and less than 1% in the cervix or ovaries. However, when pregnancies occur through medical assistance such as in vitro fertilization, 82% of ectopic pregnancies are in the fallopian tubes. A noticeably large percentage, about 11%, are heterotopic pregnancies, happening both inside and outside the womb, which is quite different from natural pregnancies. This emphasizes the importance of doctors finding out whether the pregnancy happened naturally or was medically assisted.
Why do People Need Ectopic Pregnancy, Ultrasound
An ectopic pregnancy is when a fertilized egg implants and grows outside the main cavity of the uterus, which can be dangerous. If a woman of childbearing age experiences symptoms like stomach or pelvic pain, or vaginal bleeding, doctors may suspect an ectopic pregnancy. The use of an ultrasound, which is a type of imaging technique, allows doctors to find out if the pregnancy is ectopic.
Another important test that doctors use to detect an ectopic pregnancy includes checking the levels of a hormone called beta-human chorionic gonadotropin (hCG), which is produced during pregnancy. If the test is positive, meaning the levels of beta hCG are high, doctors will need to rule out the possibility of an ectopic pregnancy before the patient is discharged from the hospital. If beta hCG is not detected, an ectopic pregnancy is unlikely, but it’s still possible. Therefore, if a woman shows symptoms of an ectopic pregnancy, a more accurate blood test for beta hCG may be done, instead of a less precise urine test.
When a Person Should Avoid Ectopic Pregnancy, Ultrasound
The only time doctors advise against using a specific type of ultrasound called transvaginal ultrasonography, is after recent gynecologic surgery. This kind of surgery is very rare in patients who might be in the early stages of pregnancy. For another type of ultrasound, called transabdominal imaging, there are no absolute situations where it cannot be used.
However, doctors have to consider various factors before deciding on which method to use. For example, patients who are overweight might not get clear images with transabdominal imaging, so they might have a better results with transvaginal imaging. However, if a patient has had injuries in the vaginal area, they might feel pain during the transvaginal approach.
The patient’s age is another important factor. Younger patients who may not have had pelvic examinations before, might feel anxious about having transvaginal ultrasonography. In such cases, doctors might start with the transabdominal imaging, using the transvaginal method as a backup option if needed.
Equipment used for Ectopic Pregnancy, Ultrasound
When a doctor examines your abdomen from the outside, using a special tool called a curvilinear probe, they typically have you lie flat on your back on a standard stretcher. This method of examination is called transabdominal imaging and is often used during pregnancy check-ups.
There’s another method of examination called transvaginal imaging. In this case, the doctor uses a different type of tool known as an endocavitary probe, which is covered with a protective sheath (usually a condom). They put some gel inside this protective cover, and some sterile water gel on the outside. This tool usually has a higher frequency than the one used for transabdominal imaging, which means it can give more detailed pictures from shallow depths when used via the vaginal approach.
The best setup for a patient undergoing transvaginal imaging is an obstetrical stretcher with supports for the legs, also known as stirrups. Alternatively, the patient may lie on a special pelvic pillow that lifts the pelvis off the bed, allowing the doctor to angle the probe’s handle below the patient’s buttocks.
Who is needed to perform Ectopic Pregnancy, Ultrasound?
Ultrasound imaging, used to check on the development of a pregnancy, can initially be done right at your bedside. This lets your doctor quickly determine if the pregnancy is developing where it should in the uterus, or if it’s developing outside the uterus in a potentially dangerous place like the fallopian tube, which is known as an ectopic pregnancy. This is especially crucial if you’re in a critical condition and there aren’t specialized pregnancy doctors available right away for guidance.
Emergency doctors have been primarily trained to do ultrasound exams involving the abdominal area, and now, more of them are learning how to perform ultrasounds that provide more detailed views of the female reproductive system by using a different method. Sometimes, these first ultrasound exams can provide a diagnosis. However, many times, these initial exams cannot definitively answer all questions on whether the development is normal or not.
Studies have shown that when the initial ultrasound exam doesn’t give clear results, there may be increased risks for both mother and baby. This underlines the importance for these patients to have more in-depth ultrasound scans done by technicians who have advanced training in this area.
Preparing for Ectopic Pregnancy, Ultrasound
A transabdominal examination is a type of ultrasound where a device, like a curvilinear probe, is used on the outside of your belly. This is done to get a picture of what’s happening inside your body. For a clear picture, it’s crucial that you drink lots of fluids beforehand so your bladder is full. This can be done through drinking water or taking fluids through a tube attached to your vein, depending on how quickly the scan must be done. The full bladder acts like a window, allowing the sound waves from the ultrasound to travel better and create a clearer image.
Please note, this process might sometimes make it hard to see certain areas in the image because of an effect called “posterior enhancement”. This happens when sound waves pass through the fluid-filled bladder and amplify, leaving a bright area in the image, making it difficult to see. Adjusting the image settings to correct this might be tricky. During this examination, you’ll be asked to wear a hospital gown, and sheets will be used to cover you up as much as possible.
On the other hand, a transvaginal examination is another type of ultrasound where the probe is inserted into the vagina. For this procedure, your bladder needs to be empty. You’ll be made to lie down in stirrups on a specific type of bed called an obstetrical stretcher. Sometimes, a special pillow is also used to lift your hips off the bed.
For the probe to work properly and safely, it’s covered with a special sheath, usually a latex condom or a similar synthetic material. A special type of gel is applied under the condom to help the ultrasound waves work better – but no air bubbles should be left on the probe head, as these can block the waves. Another type of gel, which is sterile and safe for your body, is applied on the outside of the condom. This is because some people may find the ultrasound gel irritating, and there might also be a small chance of it causing an infection. During the scan, the probe depth may need to be adjusted for the best view.
How is Ectopic Pregnancy, Ultrasound performed
When a woman is pregnant, it’s important to monitor her health and the health of her baby. Sometimes, one way of doing this is through obstetrical examinations. These tests are designed to keep the amount of radiation a pregnant woman is exposed to as low as possible. This practice, known as “as low as (is) reasonably achievable” or ALARA, is a standard in healthcare to ensure patient safety.
The main kind of obstetrical examination is done either through the abdomen or the vagina to look for a condition called ectopic pregnancy (when the fertilized egg grows outside the womb).
For a transabdominal examination, you’d lie on your back on a stretcher and a healthcare provider will use a handheld device, a probe, to capture pictures of your abdomen. These images will show your bladder and uterus clearly. It’s crucial to focus on a specific part in the middle of the uterus referred to as ‘endometrial stripe’. Misinterpreting other parts could mistakenly identify an ectopic pregnancy as an intrauterine pregnancy. The provider will slowly move the probe across your abdomen in different directions to capture complete images of the uterus. They will also look for fluid or masses near the uterus as these are signals of potential ectopic pregnancy.
Transvaginal examinations are done by inserting a probe inside the vagina, about 1-2 inches. The probe captures pictures of the bladder and their relationship with the uterus. Seeing these two close to each other means the exam is properly focused on the right area. The provider will carefully move the probe in different directions to capture the best images of your uterus and the surrounding tissue. Like the transabdominal exam, they will look for signs of fluid or masses that could indicate an ectopic pregnancy. If the tests show that there’s no intrauterine pregnancy and your beta hCG levels are above 2000, it’s possible that you might have an ectopic pregnancy.
What Else Should I Know About Ectopic Pregnancy, Ultrasound?
Ectopic pregnancy is a serious condition where the pregnancy develops outside the uterus (often in a fallopian tube). Detecting it quickly is important because it can result in serious complications if not treated promptly. Doctors both in the emergency and obstetrics departments are trained to identify signs of an ectopic pregnancy quickly.
Ultrasonography, or ultrasound, helps doctors review images in detail for signs of the condition. They look for a tell-tale sign of the pregnancy developing outside the uterus. However, it can be tough as this sign appears only in a few cases of ectopic pregnancy.
In addition to the ultrasound, doctors also look at the levels of a hormone called beta hCG which increases during pregnancy. When a pregnancy is inside the uterus, we can usually see it on a transvaginal ultrasound. If the levels of this hormone rise but doctors don’t see a pregnancy where it should be (inside the uterus), they may consider the possibility of an ectopic pregnancy.
The term “discriminatory zone” refers to the level of the hormone beta hCG when we should normally be able to see a pregnancy in the uterus. Some practitioners suggest that if beta hCG levels rise to between 1500 and 2000 mIU/mL, they should be able to see the pregnancy in the uterus, if it’s there. However, lower levels can also indicate a risk.
Ultrasound images may show an empty uterus (no pregnancy detected), a fake pregnancy sac inside the uterus, thick lining of the uterus, or blood in a space behind the uterus. These are signs that there might be an ectopic pregnancy.
Examining the fallopian tubes and ovaries can also reveal signs of an ectopic pregnancy. Detection of cysts or masses outside the uterus along with high levels of beta hCG can be a strong indication of an ectopic pregnancy.
Understanding and identifying these signs early can help doctors in diagnosing and treating ectopic pregnancies, preventing severe health complications.
